Meteotsunamis in the area of the Southern Kuril Islands: observations and numerical modeling

Meteotsunamis in the area of the Southern Kuril Islands: observations and numerical modeling | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Meteotsunamis in the area of the Southern Kuril Islands: observations and numerical modeling Georgy Shevchenko, Artem Loskutov, Alexander Shishkin This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7080527/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Mar, 2026 Read the published version in Natural Hazards → Version 1 posted 4 You are reading this latest preprint version Abstract Meteotsunamis are frequent along the coasts of Sakhalin Island and the Kuril Islands, with one or two occurrences typically recorded each year. The most pronounced meteorologically induced long-wave oscillations observed in bays exhibiting strong resonant characteristics—features that are common throughout the Russian Far East. While meteotsunamis generally pose a moderate hazard, their impact can be significant for ports and vessels, although substantially lower compared to seismic tsunamis. The development of the network of tsunami detectors of the Russian Tsunami Warning Service in main ports of the Kuril Islands, as well as the establishment of autonomous bottom pressure recorders of the Institute of Marine Geology and Geophysics of Far Eastern Branch of Russian Academy of sciences in the coastal area of Southern Kuril Islands (mainly in the bays of Shikotan Island) made it possible to record several meteorologically-induced anomalous sea level oscillation similar to tsunamis during 2009‒2020. We examined in detail the event that occurred in the Southern Kuril Islands on October 16, 2011, recorded by six bottom pressure gauges, and accompanied by digital measurements of surface atmospheric pressure at three sites. Dangerous sea-level oscillations, with a maximum trough-to-crest height of approximately 75 cm in Malokurilskaya Bay, were generated by the passage of an atmospheric front characterized by a pressure drop of approximately 6 mbar and an eastward propagation speed of 100 km/h. A similar generation mechanism was responsible for the most significant meteorological tsunami recorded in the Russian Far East, which occurred on October 1, 2018. The trough-to-crest wave height reached approximately 2 meters along the ocean side of Shikotan Island, an amplitude comparable to that of a moderate seismic tsunami. Numerical simulations of long-wave generation induced by atmospheric disturbances demonstrate that a rapidly propagating atmospheric front along the Lesser Kuril Ridge can produce hazardous sea-level oscillations in the bays of Shikotan Island. This effect arises due to the near-resonant relationship between the front's propagation speed and the phase velocity of long ocean waves approaching the island from both its southeastern and northwestern sides. Two additional events are briefly described. The analysis demonstrates that meteotsunami impacts in the Southern Kuril Islands predominantly arise from Proudman resonance, closely matching the propagation speeds of atmospheric fronts and long ocean waves. Our high-resolution numerical modeling approach elucidates critical resonant mechanisms, directional dependencies, and highlights pronounced bay-specific responses, significantly enhancing regional hazard assessment capabilities. Meteotsunamis Seiches Atmospheric pressure Numerical modelling Spectral analysis Southern Kuril Islands Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 1 Introduction Following the strong Simushir earthquake and associated tsunami of 15 November 2006, a network of bottom pressure recorders (BPRs) was deployed by the Institute of Marine Geology and Geophysics (IMGG), Yuzhno-Sakhalinsk, Russia, in bays and harbors of the Southern Kuril Islands, including offshore areas near Shikotan, Kunashir, and Iturup (Shevchenko et al. 2011a ). With a view to discover the local resonant characteristics of various bays and harbors, we analyze long-term time series of background sea-level oscillations and estimate the topographic admittance functions for each site, using spectral methods. The deployed instruments recorded several tsunamis, including the 2007 and 2009 Kuril Islands (Simushir) events, as well as the 2009 Samoa, 2010 Chile, and 2011 Tohoku tsunamis (Shevchenko et al. 2011b , 2013 , 2014b , a ). Fortunately, during these measurements several strong meteorological tsunamis were also detected. The analysis of these events constitutes the primary objective of the present study. In recent decades, considerable attention has been devoted to meteorological tsunamis in various oceanic regions. In particular, the Mediterranean Sea has emerged as a focus of research due to the abundance of bays with pronounced resonant characteristics and the frequent occurrence of intense atmospheric disturbances conducive to meteotsunami generation (Rabinovich and Monserrat 1998 ; Vilibić 2005 ; Monserrat et al. 2006 ; Vilibić et al. 2008 , 2015 ; Thomson 2010 ; Šepić et al. 2015 ; Ličer et al. 2017 ; Heidarzadeh et al. 2020 ). These two factors—resonant bay geometry and favorable atmospheric forcing—are critical for the generation of hazardous sea-level oscillations in coastal areas hosting ports and other infrastructure. Similar topographic and meteorological conditions are characteristic of the Southern Kuril Islands, particularly Shikotan Island, which features numerous bays with pronounced resonant responses and is frequently affected by thunderstorms and fast-moving atmospheric fronts capable of triggering meteotsunamis (Rabinovich and Levyant 1992 ; Rabinovich 1993 ; Rabinovich and Monserrat 1996 , 1998 ). However, in this region, meteorological tsunamis have received considerably less scientific attention. Even though the IMGG has been conducting long-term monitoring of long-wave processes—within the tsunami-period band—on the shelf and in the bays of Shikotan Island using seafloor pressure recorders (both cable-connected and autonomous), these phenomena remain underexplored. This relative lack of attention is likely due to the predominance of seismic tsunamis in the region, which pose a significantly greater hazard to coastal settlements along the Southern Kuril Islands. The continental slope adjacent to the Southern Kuril Islands corresponding to the western flank of the Kuril deep-sea trench is among the most seismically active regions in the world. Large magnitude, tsunamigenic undersea earthquakes are frequently observed in this area. In addition, hazardous waves have often been recorded during remote tsunamis generated by major subduction-zone earthquakes off the eastern coast of Japan and the coast of Chile (Shevchenko et al. 2011a , 2014b , 2017 , 2019 ). In contrast, relatively few studies have focused on meteorological tsunamis in the Southern Kuril Islands. One of the earliest documented cases appears in the monograph (Rabinovich 1993 ), which describes a sharp intensification of seiche oscillations in Krabovaya, Otradnaya, and Malokurilskaya Bays on 8 May 1991 during the passage of a thunderstorm front. This event, along with two others occurring around the same time, was analyzed in more detail by (Rabinovich and Monserrat 1998 ). A particularly rare and noteworthy case, in which meteotsunamis were not associated with resonance inside a bay but rather with a group of edge waves propagating along the Pacific coast of Shikotan Island, was described by (Litvin et al. 2000 ). This event was recorded in September 1989 by three seafloor pressure stations located on the shelf. A couple of relatively weak meteorological tsunamis along with weak seismic tsunamis were considered in (Shevchenko et al. 2011a ). A more significant event caused by the passage of an atmospheric front along the Lesser Kuril Ridge was briefly analyzed in (Kovalev et al. 2017 ). In that study, both autonomous bottom pressure recorders (BPRs) operated by IMGG and telemetric tsunami sensors maintained by the Roshydromet Tsunami Warning Service (TWS) were utilized. This meteotsunami event is examined in greater detail in the following sections. The meteotsunami with the highest wave height recorded on October 1, 2018, in Dimitrova Bay on the ocean coast of Shikotan Island had a similar generation mechanism. The identity of the mechanisms of generation of the two most dangerous events prompted us to perform numerical modeling of the response in the Southern Kuril Strait and on the Pacific shelf of the Lesser Kuril Ridge to a rapidly moving atmospheric front. The results of the analysis of observational data and numerical modeling are presented below, and two weaker events unrelated to atmospheric fronts are also briefly considered. One of them was caused by a severe thunderstorm, the other was probably caused by internal gravitational waves in the atmosphere. 2 Meteotsunami on October 16, 2011 The Meteotsunami of October 16, 2011, was recorded by IMGG BPRs in 3 bays of Shikotan Island: Tserkovnaya Bay on the Pacific coast and Krabovaya Inlet and Malokurilskaya Bay on the coast of Yuzhno-Kurilsky Strait (Fig. 1 ). Two BPRs were installed in the Malokurilskaya Bay - one of them in the inner area and another one outside (near the entrance). The fifth gauge was installed in the Yuzhno-Kurilsk seaport (Yuzhno-Kurilskaya Bay, Kunashir Island). Meteotsunami was also detected by TWS recorder which located in Kurilsk seaport (Kitovy Bay, Okhotsk Sea coast of Iturup Island). Surface atmospheric pressure was measured using digital weather stations installed in Yuzhno-Kurilsk and Kurilsk settlements in autumn 2010. These stations were equipped with high-sensitive barographs recording at temporal resolution of 1 minute, which was well suited for analyzing the atmospheric disturbances responsible for meteotsunami generation. In addition, a bottom pressure recorder kept in the IMGG laboratory in Malokurilsk was activated for testing purposes and also recorded atmospheric pressure variations. In this situation the seafloor recorder was positioned on a high hill, thus observing lower absolute pressure values compared to the other stations. However, no altitude correction was applied, as only the relative pressure variations were of interest in this study. Figure 2 presents atmospheric pressure records obtained during a 24-hour period on October 15–16, 2011. A notable rapid drop in atmospheric pressure—from 995.6 to 990 mbar within less than one hour—was recorded by the Malokurilsk bottom gauge. At Yuzhno-Kurilsk, the minimum pressure (996.8 mbar) coincided in time with a local maximum at Malokurilsk. The pressure decrease recorded at the Kurilsk station was more pronounced (from 1002.5 to 995.0 mbar) but occurred over approximately two hours. Moreover, the pressure minimum at Kurilsk was observed about 50 minutes later than at Malokurilsk and approximately 105 minutes later than at Yuzhno-Kurilsk. No periodic atmospheric pressure oscillations, the typical pattern of internal gravity waves, which can sometimes be generated by atmospheric disturbances, were identified either before or after the passage of the front. Small-amplitude, high-frequency pressure fluctuations were observed only at the Malokurilsk gauge and were not detected by the other stations. Figure 2 on the right shows the spectral density plots calculated from 5-hour time interval containing an atmospheric front starting at 11 p.m. of October 15 (related to meteotsunami) and its previous one (background spectra) at Malokurilsk. The calculation was carried out on 2-hour segments with half shifts; the number of freedom degrees equals 8. The passage of the atmospheric front caused a significant (about an order of magnitude) increase in the energy of atmospheric pressure fluctuations at periods of 2.5 to 12 minutes. This increase was relatively uniform, with no pronounced peaks in the spectrum. We found a less significant effect found on periods of up to 2 hours. In a sense, this increase compared with ordinary meteorological conditions can be considered as the spectrum of the meteotsunami source for Shikotan Island. The increase in the energy of pressure fluctuations was smaller at other stations where the atmospheric front was weaker expressed. An approximate calculation indicated that the atmospheric front moved eastward at a speed of about 100 km/h. Comparable estimates of the cyclone velocity—with a central pressure around 1000 hPa—and its associated atmospheric fronts were obtained using surface atmospheric pressure maps available from an open-access website (NOAA 2018 ) (Fig. 3 ). Notably, while atmospheric disturbances propagated at approximately 100 km/h in the southern part of the Kuril Islands, their speed decreased to about 50 km/h in the central part of the Kuril Ridge. The propagation speeds of atmospheric fronts in the vicinity of the Southern Kuril Islands closely matched the phase velocities of long waves in the coastal region (Fig. 4 ). In particular, the long-wave propagation speeds from both the southeastern and northwestern directions towards Shikotan Island are near 100 km/h. This condition is especially significant for efficient generation of intense oscillations within the bays of the island, a conclusion corroborated by the numerical modeling results presented below. De-tided sea-level records obtained on October 15–16, 2011 (covering a one-day interval) from the bays of Shikotan Island and the seaports of Yuzhno-Kurilsk and Kurilsk are presented in Fig. 5 . In Krabovaya and Malokurilskaya Bays—both at the inner site and near the bay entrance—the onset of the meteotsunami is clearly identifiable, beginning at 01:28, nearly coinciding with the passage of the atmospheric pressure minimum over Shikotan Island. Sea-level oscillations associated with the meteotsunami persisted for approximately 10 hours. Identifying the onset of the meteotsunami in Tserkovnaya Bay and Yuzhno-Kurilskaya Bay proved somewhat more challenging. On the Pacific coast of Shikotan Island (Tserkovnaya Bay), the meteotsunami likely began approximately 6 minutes later than in Krabovaya Bay, whereas in Yuzhno-Kurilsk the onset was observed around 10 minutes earlier. The amplitudes of sea-level oscillations in these bays were significantly smaller. At the Kurilsk seaport, the meteotsunami appeared as high-frequency, small-amplitude fluctuations. Statistical characteristics of the meteotsunami—such as trough-to-crest wave heights and arrival times of the first and maximum waves—were not evaluated for this station but for the other sites provided in Table 1 . Table 1 Statistical characteristics of meteotsunami on October 16, 2011, from the bottom pressure gauges on the Pacific coast of Russia Station First wave Maximum wave Height (cm) Arrival time Height (cm) Arrival time Yuzhno-Kurilsk Crest 4.7 1:18 14.6 4:18 Trough -5.0 1:33 -10.8 4:31 Tserkovnaya Crest -1.1 1:34 25.0 3:35 Trough -10.4 1:41 -16.1 3:43 Malokurilskaya (Out) Crest 3.3 1:28 -15.4 1:36 Trough -15.4 1:36 13.6 1:46 Malokurilskaya (In) Crest 5.6 1:29 37.2–40.7 1:47 − 2:21 Trough -27.8 1:38 -37.3-32.7 1:56 − 2:29 Krabovaya Crest 4.4 1:28 25.4 2:18 Trough -30.6 1:17 -24.8 2:37 Overall, the initial waves of the meteotsunami were recorded at all stations nearly simultaneously with the passage of the atmospheric front, supporting the interpretation of a common generation mechanism. The near-synchronous onset of oscillations both at the entrance and in the inner part of Malokurilskaya Bay is of particular interest. The maximum wave heights, their arrival times, and the durations of meteotsunami-induced oscillations varied among the bays, primarily due to differences in local resonance characteristics governed by bathymetry. This variability is most clearly illustrated in the frequency–time diagrams presented in Fig. 5 . In bays with pronounced resonant properties—specifically Malokurilskaya and Krabovaya Bays—well-defined energy bands are observed, although at different frequencies. In contrast, in Yuzhno-Kurilskaya Bay, where resonance is weakly expressed, the spectral energy is more broadly distributed across a range of frequencies. The most pronounced sea-level oscillations were observed in Malokurilskaya Bay, which is known for its strong resonant response characteristics (Rabinovich and Levyant 1992 ). The most hazardous wave group consisted of six oscillations, with trough-to-crest heights exceeding 50 cm. Such waves could pose a threat to vessels anchored within the bay and generate strong currents in the channel connecting the bay to the Pacific Ocean, potentially hindering vessel navigation. Two additional wave groups, with trough-to-crest heights ranging from 25 to 30 cm, were recorded during other time intervals. Overall, the pattern of sea-level oscillations during the meteotsunami resembled that observed during moderate seismic tsunamis in the bays of the Southern Kuril Islands (Shevchenko et al. 2011a , 2013 ). In contrast, the meteotsunami posed a lower hazard to the seaports located in Krabovaya, Yuzhno-Kurilskaya, and Kitovy Bays. In Krabovaya Inlet, maximum wave heights reached 50 cm, while in the other bays the amplitudes were smaller. Figure 6 shows spectral density plots calculated from 17-hour segments of de-tided sea-level records that include the meteotsunami event (beginning at 22:00 UTC on October 15) as well as the preceding interval used to compute background spectra. The analysis was performed for multiple bays of the Southern Kuril Islands. At all stations, spectral energy increased across a broad frequency band corresponding to wave periods between 2 and 100 minutes. In Tserkovnaya Bay, meteotsunami-induced oscillations spanned a wide range of periods; however, the most pronounced increase in spectral density was observed in the 5–20-minute band—close to the dominant zero-mode resonance period of the bay—as well as at a longer period near 50 minutes. The spectral peak near 50 minutes does not correspond to any known resonant mode of the bay itself and is likely associated with the resonant characteristics of the adjacent shelf zone. A similar spectral feature was observed in 1991 during a meteotsunami event recorded on the oceanic shelf of Shikotan Island (Litvin et al. 2000 ), suggesting a broader regional origin for this component. In the spectrum of sea-level oscillations recorded near the entrance to Malokurilskaya Bay—both during the meteotsunami event and under calm conditions—a well-defined peak was identified at a period of approximately 17.5 minutes. This spectral feature corresponds to the bay’s fundamental (zero-mode) resonance, characterized by a nodal line near the bay entrance. The presence of oscillatory energy at this location is therefore consistent with the expected spatial distribution of this mode. A second, more intriguing spectral peak was observed at a period of approximately 5.5 minutes, which was absent in the spectrum from the bay’s inner region. The physical origin of this shorter-period component remains unclear and warrants further investigation. At the station located in the inner part of Malokurilskaya Bay, spectral peaks at periods of approximately 17.5, 4.5, and 3 minutes—corresponding to the natural resonant modes of the bay—were clearly identified in both the meteotsunami and background segments. Notably, for the two higher-frequency peaks, the increase in spectral energy during the meteotsunami was minimal, significantly lower than the energy growth observed at other frequencies. In Krabovaya Bay, both the meteotsunami and background spectra exhibit a strong, well-defined peak at a period of approximately 30 minutes, which corresponds to the bay’s fundamental (zero-mode) resonance. The geometry of Krabovaya Bay—characterized as a classic fjord, i.e., a narrow, elongated, and deep embayment with a relatively wide mouth—favors amplification of the primary resonant mode toward the head of the bay, where the seaport and bottom pressure recorder were located. In the spectral analysis of Yuzhno-Kurilskaya Bay, the most significant increases in energy were observed at periods of approximately 25 minutes (associated with the bay’s resonant mode) and 45 minutes. The latter is likely related to the natural oscillation period of the Yuzhno-Kurilsky Strait, in agreement with previous estimates by (Rabinovich 1993 ). In contrast, spectral energy at the Kurilsk seaport increased only in the high-frequency range, specifically in the 2–6-minute band. The approach proposed in (Rabinovich 1997 ), which involves computing the ratio of tsunami to background spectra provides a means of minimizing the influence of local bathymetric features and isolating the spectral characteristics of the forcing mechanism. We applied this method to the October 16, 2011, meteotsunami in the region of the Southern Kuril Islands. The resulting spectral ratios reveal a broad and relatively uniform increase in sea-level oscillation energy over the 5–60-minute period band at all stations, except for Kurilsk. No distinct spectral peaks were detected at any location, suggesting the absence of localized resonant amplification within this range. Overall, the pattern of energy amplification in the sea-level spectra closely resembles the spectral enhancement observed in atmospheric pressure fluctuations at Malokurilsk during the passage of the atmospheric front. For shorter periods (< 5 minutes), the increase in spectral energy was significantly weaker. A similar broadband amplification pattern was reported for the 2010 Chilean tsunami, although that event also exhibited enhanced energy at lower frequencies (Shevchenko et al. 2013 ). We also analyzed the sea-level record obtained from the deep-ocean DART 21401 gauge, located in the region adjacent to the Southern Kuril Islands. Visual inspection of the de-tided time series for October 16 did not reveal any apparent amplification of oscillations. However, the frequency–time diagram for October 15–16 exhibited a noticeable increase in spectral energy between 1500 and 2000 minutes from the start of the record. This amplification occurred within the 5–50-minute period band, which is consistent with the spectral characteristics observed at coastal stations. Nonetheless, in the open ocean, the magnitude of these oscillations was small, with the maximum spectral amplitude not exceeding 1.6 mm. This example highlights the predominantly local nature of meteotsunamis and their strong dependence on the resonant properties of coastal bays and the adjacent shelf zone—an observation that aligns with the established understanding of meteotsunami dynamics (Rabinovich and Šepić 2016 ). 3 Meteotsunami on October 1, 2018 The characteristic surface atmospheric pressure variations were measured at the hydrophysical observatory on Shikotan Island (uncorrected to sea level) and by a digital weather station operated by the Kurilsk Hydrometeorological Service (HMS) on Iturup Island on September 30 – October 1, 2018. Figure 7 represents the time series of recorded pressure disturbances. The pressure drop during the cyclone’s passage over Shikotan Island was only slightly greater—by several hPa—than that recorded on Iturup Island, despite the latter likely being farther from the cyclone center. However, the pressure change associated with the passage of the atmospheric front was considerably more abrupt: pressure at the observatory dropped by 7 hPa within 10 minutes and returned to its original level over the following 10 minutes. A similar, though less intense, pattern was observed at the Kurilsk station, where atmospheric pressure fell by 3 hPa and recovered within a comparable timeframe. As it shown in weather maps on Fig. 8 , at 2:49 UTC, a deep cyclone—with a central pressure of 973 hPa—was located southeast of Hokkaido Island, near the city of Kushiro. The cyclone was associated with both warm and cold fronts. By 09:02 UTC, the cyclone’s center had shifted to a position offshore of Urup Island, having traveled approximately 600 km in six hours. This corresponds to an average propagation speed of ~ 100 km/h for the atmospheric disturbance and its associated frontal structures. The time interval between the pressure minima at the two stations was exactly one hour. The straight-line distance between the stations is approximately 130 km, while the distance measured along the cyclone’s estimated trajectory is about 115 km. Based on this, the speed of the atmospheric disturbance is estimated at approximately 115 km/h—a value likely more reliable than estimates derived from surface pressure map analysis alone. This suggests that the cyclone accelerated significantly—by a factor of about 1.5—as it approached the Southern Kuril Islands compared to its earlier trajectory along Hokkaido Island. Figure 9 presents 12-hour segments of de-tided sea-level recorded on October 1, 2018, at the Kushiro and Hanasaki stations (Japan), as well as in Yuzhno-Kurilskaya, Otradnaya, Malokurilskaya, and Dimitrova Bays (the Southern Kuril Islands), along with their corresponding frequency–time diagrams. Statistical characteristics of the meteotsunami event—including trough-to-crest wave heights and the arrival times of the first and maximum waves—are summarized in Table 2 . The initial high-amplitude waves were recorded at Kushiro station. Although it is difficult to unambiguously determine the exact onset time of the meteotsunami in the time series, it can be inferred from the frequency–time diagram by a shift in the dominant frequency content. Specifically, the meteotsunami induced lower-frequency oscillations compared to background conditions, a pattern that is clearly evident in the diagram. These relatively long-period oscillations, with a dominant period of approximately 30 minutes, persisted for nearly 8 hours and are attributed to the meteotsunami. Subsequently, the character of the wave field changed markedly, returning to its typical state in which high-frequency components again dominated the sea-level variability. This transition is clearly visible in the frequency–time diagram, where the band of spectral maxima shifted abruptly from approximately 0.03 cycles per minute to 0.2 cycles per minute. The maximum wave—exhibiting a trough-to-crest height of 70 cm—was recorded about 1.5 hours earlier than in the port of Hanasaki, where the meteotsunami posed a more serious hazard, with a maximum wave height of 110 cm. The structure of sea-level oscillations at Hanasaki was similar to that observed at Kushiro station: a weak leading wave, followed by a high-amplitude wave, and then a series of long-lasting, slowly decaying oscillations with dominant frequencies lower than the background variability. Given the approximate distance of 110 km between the stations, the velocity of the atmospheric disturbance responsible for the anomalous oscillations can be estimated at around 75 km/h. According to the frequency–time diagram, the main energy of the meteotsunami was concentrated in the 0.05–0.06 cycles per minute range, corresponding to a dominant period of ~ 18 minutes—likely associated with a resonant mode of Hanasaki Bay. A secondary contribution was observed at a period of approximately 35 minutes. The decay of oscillation amplitude at Hanasaki was slightly slower than at Kushiro, although the total duration of the event at both locations was approximately 8 hours. The meteotsunami was also recorded on the Pacific coast of Shikotan Island by a bottom pressure recorder (BPR) deployed in Dimitrova Bay, located approximately 115 km from the Hanasaki station. In this location, the nature of the wave process differed somewhat from that observed at the Japanese stations and was more typical of bays exhibiting stable resonant behavior. Instead of a single dominant wave, a wave group with the highest amplitude concentrated near the center was observed. The maximum recorded trough-to-crest wave height reached 188 cm, representing the largest meteotsunami ever observed along the coast of the Kuril Ridge—and, more broadly, in the entire Russian Far East. This wave height is comparable to that produced by moderate-intensity seismic tsunamis, typically defined as events with amplitudes on the order of 2 m. Such waves pose a tangible hazard to vessels and coastal infrastructure located in nearshore zones. However, this event occurred on the uninhabited Pacific coast of Shikotan Island, where no permanent settlements currently exist. Table 2 Statistical characteristics of meteotsunami on October 1, 2018, from the bottom pressure gauges on the Pacific coast of Russia and Japan Station First wave Maximum wave Height (cm) Arrival time Height (cm) Arrival time Kushiro Crest 27 0:42 53 1:27 Trough 8 0:51 −17 1:44 Hanasaki Crest 35 2:11 78 2:59 Trough 17 2:00 −32 3:10 Dimitrova Crest 9 3:01 97 4:05 Trough -10 2:54 −92 4:15 Malokurilskaya Crest 35 3:51 41 5:16 Trough -51 3:38 −61 5:26 Otradnaya Crest 57 3:58 57 3:58 Trough −34 3:43 −34 3:43 Yuzhno-Kurilsk Crest 4 3:27 51 4:25 Trough -8 3:17 16 4:44 In the frequency–time diagram, a broad energy patch is visible at the beginning of the record, indicating the onset of a meteotsunami in the frequency range of 0.04–0.08 cpm, with nearly uniform intensity across this band. The maximum spectral amplitude within this interval reached approximately 40 cm. Subsequently, a narrow, persistent energy band appears at ~ 0.06 cpm (corresponding to a period of ~ 16 minutes), which reflects the dominant resonant mode of Dimitrova Bay. The most prominent oscillations spanned the time interval from approximately 03:00 to 12:00 local time—about one hour longer than the duration observed at the Japanese stations. This extended duration is likely attributed to the more pronounced resonant characteristics of Dimitrova Bay, which typically enhance both the persistence and amplitude of long-wave oscillations. Let us now consider the records obtained along the coast of the Southern Kuril Strait. In both Otradnaya Bay and Yuzhno-Kurilskaya Bay, the pattern of sea-level oscillations was generally similar and closely resembled that observed along the coast of Hokkaido—characterized by an initial high-energy impulse followed by gradually decaying oscillations. A notable feature of the wave process in Otradnaya Bay was the presence of a distinct initial negative displacement, which was immediately followed by a strong positive pulse reaching 57 cm in trough-to-crest height. On Kunashir Island, the oscillations began with relatively weak fluctuations but were followed—approximately 30 minutes later than in Otradnaya Bay—by a pronounced positive peak. The reason for this temporal offset between two geographically proximate locations remains unclear. In both bays, low-frequency oscillations persisted for approximately 11 hours, gradually decreasing in amplitude over time. The frequency–time diagram for Otradnaya Bay reveals a broad spectral maximum during the initial phase of the record. The spectral energy was distributed relatively evenly across the 0.02–0.05 cycles per minute (cpm) range, after which the dominant energy became concentrated within a narrower band between 0.03 and 0.04 cpm. In Yuzhno-Kurilskaya Bay, the spectral composition of the sea-level oscillations was more complex, with elevated energy observed across a wider frequency range from 0.02 to 0.08 cpm. This broadband response is characteristic of basins with relatively weak frequency-selective properties, where multiple modes may be excited simultaneously without a dominant resonant frequency. In Malokurilskaya Bay, where the fundamental (zero-mode) resonance with a period of approximately 19 minutes is persistently present in the sea-level records, it is particularly difficult to accurately determine the onset and termination of wave events—whether tsunami or meteotsunami. Notably, as in Otradnaya Bay, located only a short distance away, the meteotsunami-induced oscillations began with a pronounced negative sea-level excursion exceeding 50 cm. The corresponding trough-to-crest wave height reached 86 cm. The event initially manifested as a wave group consisting of seven oscillations, within which the third wave was the smallest in amplitude, while the sixth was the largest. An additional four wave groups associated with the meteotsunami were identified in the Malokurilskaya Bay record, with amplitudes gradually decreasing over time. The final group was observed between 18:30 and 22:30 UTC and exhibited a maximum trough-to-crest wave height of 34 cm—still a substantial value in the context of non-seismic sea-level disturbances. The dominant oscillation energy was concentrated within a narrow frequency band ranging from 0.05 to 0.07 cycles per minute (cpm), except during the initial phase, when lower-frequency oscillations (~ 0.04 cpm) were also present. The Fig. 10 additionally shows comparative spectral analyses of sea-level oscillations recorded during the meteotsunami and corresponding background noise. At Dimitrova Bay, spectral peaks during the meteotsunami event prominently appear at periods of approximately 16.4, 7.8, 5.8, and 3.1 minutes, significantly exceeding background energy levels. Such multiple spectral peaks suggest resonance patterns characteristic of the bay's basin complex geometry. Malokurilskaya Bay displays notable energy peaks at approximately 17.5, 4.1, and 3.1 minutes, also markedly elevated above background conditions. The dominant peak at 17.5 minutes likely corresponds to the fundamental resonant mode of the bay, whereas shorter-period peaks indicate higher-order resonance effects. In Otradnaya Bay, the spectral analysis identifies a clear dominant energy peak around 30 minutes, substantially above the background, indicative of a single dominant resonance mode in this locality during meteotsunami events. At Yuzhno-Kurilskaya Bay, a similar pattern emerges with a pronounced peak around a 27-minute period. This suggests that the bay's resonant characteristics concentrate wave energy within a narrower frequency band, enhancing local impacts during meteotsunami occurrences. The station at Hanasaki reveals a distinct bimodal spectral structure with peaks at approximately 22.5 and 8.6 minutes. Both peaks significantly exceed the 95% confidence threshold, emphasizing their statistical significance over background fluctuations. Lastly, Kushiro station exhibits a notable energy peak at approximately 30 minutes, with additional minor yet statistically meaningful peaks observed at 12.9 and 5.1 minutes. These multiple peaks indicate complex spectral responses likely associated with local bathymetric or coastal geometrical features. Collectively, the spectral characteristics outlined above underscore the site-specific resonant responses of coastal locations to meteotsunami forcing, highlighting the importance of detailed local bathymetric and morphological analyses. 4 Other examples of meteotsunami recording in the Southern Kuril Islands August 3–4, 2010. Another meteotsunami event was recorded in Malokurilskaya and Yuzhno-Kurilskaya Bays on August 3–4, 2010, with maximum trough-to-crest wave heights of 42 cm and 39 cm, respectively (Fig. 11 ). The anomalous sea-level oscillations were associated with a severe thunderstorm that also caused an electric power blackout across the Southern Kuril Islands. Unfortunately, no digital atmospheric pressure measurements were available for this event, and therefore the exact characteristics of the pressure fluctuations associated with the thunderstorm remain unknown. The sea-level response was particularly unusual, especially in Yuzhno-Kurilskaya Bay. This bay is generally characterized by weak resonant properties and typically exhibits a much lower response to external atmospheric forcing compared to Malokurilskaya Bay, which displays strong resonant amplification. However, during this meteotsunami event, the responses in both bays were of comparable amplitude. Spectral density analysis of sea-level fluctuations during the event (Fig. 12 ) showed a relatively uniform increase in energy over a broad period range from 4 to 60 minutes. No distinct spectral peak was observed at any specific frequency in Yuzhno-Kurilskaya Bay, suggesting a non-resonant response—an atypical feature for meteotsunami-related sea-level disturbances. In Malokurilskaya Bay, the most significant energy increase occurred within the 25–60-minute period range, while the response at the known resonance periods of 4.5 and 19 minutes was notably weaker. This indicates that the sea-level response in this bay to the passing thunderstorm was also highly unusual and did not follow the typical resonance-dominated pattern. October 6–7, 2018. Another meteotsunami event, more precisely, two successive events within a single day—was recorded one week after the strongest meteotsunami on October 1, 2018. Although significantly weaker, well-defined sea-level oscillations were observed in several bays of Shikotan Island. Sea-level records obtained from bottom pressure recorders (BPRs) in Otradnaya, Dimitrova, and Malokurilskaya Bays, were obtained. In Dimitrova Bay, wave groups with a dominant period of ~ 16 minutes—associated with the bay’s zero-mode resonance—were consistently present. Two distinct episodes of amplitude amplification were identified. The second group, observed between 04:52 and 10:16 UTC on October 7, was more intense, with a mean amplitude of ~ 12 cm, although its duration was about an hour shorter than the first. The first group was less distinguishable in the frequency–time diagram, marked primarily by sustained elevated spectral amplitudes near the 16-minute band. In contrast, the second event was clearly characterized by the appearance of additional spectral bands at ~ 0.05 and 0.03 cycles per minute (cpm). In Otradnaya Bay, initial oscillations were irregular and of low amplitude. However, around 20:00 UTC on October 6, the wave regime shifted abruptly, giving rise to regular oscillations with dominant periods between 20 and 25 minutes. These persisted through the night. At the onset of this group, a maximum wave of 32 cm was recorded, followed by stable-amplitude oscillations (~ 11 cm). Several hours later, at 05:11 UTC, another shift occurred, associated with the arrival of a distinct wave group. The leading wave in this group had a trough-to-crest height of 30 cm and was followed by four gradually decaying oscillations with slightly longer periods (~ 30 minutes). The strongest oscillations were recorded in Malokurilskaya Bay. As previously noted, this bay is characterized by persistent zero-mode resonance at ~ 19 minutes, which makes identifying the precise onset of a meteotsunami challenging. The event likely began around 20:00 UTC on October 6, coinciding with a marked increase in wave amplitude. A group of seven waves followed, with an average amplitude slightly exceeding 20 cm, the fourth wave being the largest. After a period of energy decay, a second group consisting of twelve lower-amplitude (~ 10 cm) oscillations were recorded. Later, as in Otradnaya Bay, a final group of four gradually decaying waves was observed. In contrast, the meteotsunami signals recorded in Yuzhno-Kurilskaya Bay, as well as at the Japanese coastal stations in Kushiro and Hanasaki, were negligible and are not analyzed further. A synoptic map of surface atmospheric pressure (not shown) indicates that the cyclone and its associated frontal system, unlike the event of October 1, followed a trajectory directed toward the open Pacific rather than along the Kuril Island arc. Such a cyclone track deviates from the classical meteotsunami generation mechanism involving a coherent atmospheric front propagating along the island chain, as commonly simulated in numerical models. This interpretation is supported by surface atmospheric pressure records from the Shikotan geophysical observatory (GFO) and the Kurilsk HMS. On Shikotan Island, two distinct intervals of intense pressure fluctuations were recorded: from 17:00 to 23:00 UTC on October 6 (associated with the cyclone’s leading front), and from 03:00 to 07:00 UTC on October 7 (corresponding to the passage of the cyclone center). At Kurilsk station, the cyclone’s influence was weaker, and no clear frontal passage was observed. Nevertheless, both stations registered an elevated atmospheric pressure variability starting at approximately 17:00 UTC on October 6 and continuing until 09:00 UTC on October 7, though with different amplitudes and patterns. The mechanism responsible for the generation of the observed long-period oscillations in several bays—interpreted here as meteotsunamis—appears fundamentally different from that of the stronger October 1 event. It is likely that the oscillations were driven by atmospheric pressure fluctuations within the tsunami frequency band, potentially caused by internal gravity waves in the atmosphere. However, this hypothesis cannot be confirmed definitively due to the limited availability of meteorological data. 5 Numerical Modeling and Analysis of Meteotsunami Events Near the Southern Kuril Islands A numerical simulation of the strongest meteotsunami event of October 1–2, 2018, was conducted to verify the generation mechanisms, amplification processes and estimate energy directivity. This event was selected due to its pronounced sea-level disturbances recorded by tide gauges and their clear correlation with atmospheric pressure anomalies as described above. To simulate the generation and resonant amplification of the meteotsunami, we employed a modified version of the GPU-accelerated shallow-water model TUNAMI-N2 (Imamura et al. 2006 ; Brodtkorb et al. 2012 ; Giles et al. 2014 ; Oishi et al. 2015 ), widely used in tsunami studies. The model was adapted to incorporate dynamically evolving atmospheric pressure fields as a surface forcing mechanism, thereby enabling the simulation of pressure-induced wave generation and propagation. The computational domain setup was illustrated in Fig. 1 . The outer grid encompasses the oceanic shelf surrounding the Southern Kuril Islands and serves as the primary domain for propagating long waves forced by the moving atmospheric disturbance. The domain spans from 143° 0′ 22.54″ E to 149° 1′ 37.49″ E longitude and from 41° 47′ 43.57″ N to 45° 58′ 7.58″ N latitude, with a resolution of 15 arcseconds (~ 463 m) and grid dimensions of 1446 × 1003 nodes. Bathymetric data were derived from high-resolution GEBCO datasets and refined using regional hydrographic surveys to improve topographic accuracy. Open boundaries were applied on all sides of the domain to allow outgoing wave energy to radiate freely, minimizing artificial reflections. To capture local resonant responses in individual bays and inlets, high-resolution nested grids were embedded within the outer model. Each nested domain was specifically designed to match the local bathymetry and was forced at the boundaries using interpolated sea-level data from the parent grid. The spatial parameters and configurations of the nested domains are summarized in Table 3 . Table 3 Geometric characteristics of computational subdomains Name Malokurilskaya Bay Tserkovnaya Bay Krabovaya Inlet Dimitrova Bay Yuzhno-Kurilskaya Bay Grid Size Nx 205 162 207 412 326 Ny 133 121 134 177 243 Longitudes Min 146° 46′ 19.7″ E 146° 40′ 37.99″ E 146° 41′ 51.0″ E 146° 48′ 14.04″ E 145° 47′ 16.08″ E Max 146° 49′ 43.9″ E 146° 43′ 18.98″ E 146° 45′ 17.03″ E 146° 55′ 5.02″ E 145° 52′ 41.3″ E Latitudes Min 43° 51′ 12.51″ N 43° 42′ 54.0″ N 43° 48′ 41.0″ N 43° 46′ 28.0″ N 43° 58′ 56.2″ N Max 43° 53′ 24.14″ N 43° 44′ 54.0″ N 43° 50′ 53.99″ N 43° 49′ 24.0″ N 44° 2′ 58.2″ N Resolution dL ~ 30.7 m x 30.7 m Ideally, accurate simulation of meteotsunami generation by a propagating atmospheric front requires high-resolution spatial data for the pressure field. However, even under optimal synoptic analysis conditions, the temporal resolution of available datasets is limited to one hour, which is insufficient for capturing the high-frequency dynamics of the processes investigated in this study. To construct a more temporally refined atmospheric forcing, we employed a high-resolution barometric pressure series obtained at Malokurilsk. This record was transformed into a spatial pressure field under the assumption that the atmospheric front propagated at a speed of ~ 115 km/h at an azimuthal angle of approximately 60° from true north. This propagation scenario is consistent with the structure of the pressure fields observed in synoptic weather maps. The pressure time series was expanded spatially using the assumed front velocity and original temporal discretization. The resulting dynamic pressure anomaly containing sharp depression in the vicinity of pressure wave train head extended over ~ 2,500 km and was interpolated into the numerical model as an external forcing mechanism (Fig. 13 ). The generated wave field in the outer domain (over the continental shelf of the southern Kuril Islands) was transmitted to nested coastal subdomains through boundary conditions applied at the interfaces. The model did not include local atmospheric wave generation within the bays themselves. This simplification is justified by the relatively short residence time of the atmospheric front over these small basins, which is insufficient to induce significant meteotsunami generation. Instead, the simulation focused on the resonant response of the bays to the incoming pressure-forced long waves generated over the shelf. The total simulation time was 24 hours, with a time step of 250 milliseconds in the outer domain and 1 minute in the nested domains. Synthetic tide gauge records were extracted at key stations across all grids. Model results demonstrated good agreement with observations (Fig. 14 ), capturing key features of the meteotsunami—including wave amplitudes and the spectral structure of resonant peaks. Some limitations arise from the disparity in spatial resolution between the outer and nested grids, which reduced the model’s ability to resolve bidirectional energy exchange across domain boundaries. This simplification resulted in a continuous energy influx into the inner domains and gradual amplification of oscillations. However, this effect did not significantly affect the primary objective of the simulation: to evaluate resonance amplification and directional sensitivity of individual bays to atmospheric disturbances of varying trajectories and velocities. In the recent research (Rabinovich et al. 2021 ) patterns of directivity of meteotsunami maximum simulated height were examined. Here we focus on more detailed analysis of directivity of energy response for each significant resonant peak attached to lower frequency eigen mode excited by meteotsunami. Corresponding normalized to maximum spectral power heatmaps (Fig. 15 ) computed for nearshore virtual gauges revealed patterns of spatial selectivity. The figure illustrates a set of directional resonance diagrams for four observational sites—Dimitrova, Malokurilskaya, Otradnaya, and Yuzhno-Kurilskaya bays—situated in the Southern Kuril Islands region. Each panel represents a heatmap of spectral energy concentration at specific resonant periods as functions of azimuth and propagation speed of an atmospheric pressure disturbance. The intensity of coloration indicates the relative magnitude of the resonance, with darker shading corresponding to higher resonant spectral power. In Dimitrova Bay, significant resonance peaks appear at longer periods, specifically around 40 and 20 minutes, demonstrating clear directional preference at azimuths of approximately − 90° to -120°, with predominant atmospheric disturbance speeds of approximately 110–130 km/h. The identified directional preference suggests a pronounced Proudman resonance mechanism where the atmospheric disturbance speed closely matches the local long-wave phase speed along the adjacent shelf, potentially further enhanced by shelf bathymetry aligned orthogonally to the observed azimuthal angles. Malokurilskaya Bay exhibits prominent resonance at periods around 17.8 and 5 minutes, with the most pronounced directivity at approximately − 90° and − 240° azimuths and propagation speeds ranging predominantly between 100 and 130 km/h. The distinct resonance at these shorter periods implies a significant influence of local bathymetric features, suggesting a localized shelf resonance or harbor amplification, potentially intensified by Proudman resonance conditions due to atmospheric disturbances propagating at speeds coinciding closely with local wave speed. Otradnaya Bay demonstrates clear spectral resonance at longer periods (38 and 15 minutes) predominantly aligned along azimuth − 90°, suggesting strong sensitivity to pressure disturbances propagating nearly perpendicular to the shoreline. Additionally, intermediate resonances (10 min period) show broader azimuthal distribution with peak responses at several discrete azimuthal angles (-60°, -120°, -210°), indicating combined effects of local coastal topography and broader shelf resonance conditions. Finally, Yuzhno-Kurilskaya Bay shows complex resonance patterns with pronounced energy peaks at multiple periods, notably around 23, 10.5, and 7 minutes. Resonances are directionally selective, predominantly aligned at azimuths near − 90° and − 120°, reflecting pronounced Proudman resonance effects possibly complemented by intricate interactions with the local bathymetric configuration. Resonant peaks occurring at shorter periods (5.3, 2.5 minutes) suggest additional harbor resonance mechanisms linked to highly localized topographical features within the bay. Overall, these directional heatmaps underscore the interplay between atmospheric forcing characterized by specific speeds and propagation directions, shelf resonance influenced by coastal bathymetry, and localized topographic amplification within bays. The marked directional selectivity highlights the critical importance of Proudman resonance and emphasizes the necessity of integrating detailed bathymetric and atmospheric data when assessing meteotsunami hazards in coastal regions. 6 Discussion This study presents a comprehensive analysis of two significant meteotsunami events affecting the Southern Kuril Islands, integrating long-term sea-level observations with high-resolution numerical simulations. The findings clarify the dominant generation mechanisms—particularly the role of Proudman resonance—and highlight the influence of local bathymetry, coastline orientation, and atmospheric dynamics on meteotsunami amplification. The events of October 16, 2011, and October 1, 2018, represent two of the most energetic meteotsunamis observed in this region. Spectral analyses of de-tided sea-level data revealed pronounced amplification at distinct resonant frequencies, especially in Malokurilskaya, Krabovaya, and Dimitrova Bays. These peaks, frequently around 16–20 minutes, correspond to the fundamental (zero) resonance modes and were further confirmed by frequency-time diagrams and power spectral density estimates. The concurrent presence of rapidly propagating atmospheric pressure anomalies supports the interpretation that Proudman resonance was the dominant mechanism. Proudman resonance arises when the speed of an atmospheric disturbance matches the phase speed of long gravity waves in the ocean. In both primary cases, atmospheric fronts moved eastward at speeds of approximately 100–115 km/h, closely aligning with long-wave phase speeds over the 50–200 m shelf region adjacent to the Kuril Islands. This velocity matching led to constructive interference, facilitating efficient energy transfer from the atmosphere to the ocean surface. The waveforms observed in resonant bays—featuring coherent, long-duration oscillations with high wave amplitudes—were accurately reproduced in the model simulations. The directionality of the atmospheric front relative to coastal orientation played a significant role in wave amplification. Bays aligned with the trajectory of the atmospheric front experienced greater resonance effects, particularly those with open east-facing configurations such as Malokurilskaya Bay. Spatial distributions of model-simulated wave energy revealed focused amplification patterns, strongly influenced by the bay geometry, entrance width, and depth profile. However, the analysis also exposed cases of significant sea-level oscillations without clear association with traveling pressure fronts. The events of August 3–4, 2010, and October 6–7, 2018, likely involved alternative generation mechanisms such as internal atmospheric gravity waves or localized pressure perturbations caused by thunderstorms. These cases exhibited broader spectral content and different temporal evolution, suggesting excitation through high-frequency atmospheric forcing rather than classical resonance. Notably, spectral ratios between tsunami and background signals in these cases showed non-resonant amplification across a wide period range. Such findings underscore the multifactorial nature of the meteotsunami generation. While Proudman resonance often governs large-scale events, small-scale atmospheric disturbances can also induce significant responses in coastal basins with favorable topographic conditions. This emphasizes the necessity of dense, high-resolution atmospheric and oceanic monitoring to distinguish among potential mechanisms. The numerical modeling framework provided valuable insights into the wave generation and resonance processes. However, limitations remain. The atmospheric pressure forcing was reconstructed from a single time series, assuming uniform translation speed and direction—neglecting spatial variability and synoptic-scale evolution. Furthermore, atmospheric wave dynamics, including dispersion and local convection, were not captured. The lack of two-way coupling between outer and nested domains introduced artificial energy buildup in some bays, while resolution mismatches hindered detailed wave focusing and dissipation patterns. Moreover, bathymetric smoothing at nesting boundaries may have compromised accurate wave transmission in complex geometries. These limitations suggest that while the simulations provide reliable first-order insights, further model refinement is necessary to fully capture the complex interactions governing meteotsunami dynamics. Nevertheless, validation against observational data yielded good agreement in wave amplitudes, timing, and spectral content, with correlation coefficients exceeding 0.85 and RMSE values under 3 cm. The model successfully reproduced key features of meteotsunami excitation and amplification, including the resonance-enhanced oscillations and direction-dependent energy transfer. 7 Conclusions Regular sea-level observations conducted by the Institute of Marine Geology and Geophysics (IMGG) between 2007 and 2021, primarily in the bays of Shikotan Island, have provided critical insights into the recurrence patterns and intensities of meteotsunamis in the Southern Kuril Islands. These long-term observations reveal that significant meteotsunami events, comparable in amplitude and potential impact to moderate seismic tsunamis, occur relatively infrequently—approximately once every three to five years. Such substantial events are typically generated by fast-moving atmospheric fronts traveling at speeds close to 100 km/h, conditions ideal for triggering Proudman resonance and resulting in pronounced sea-level oscillations. In contrast, less intense meteotsunamis occur with higher frequency, averaging about twice per year. Although these events pose a lower risk, their persistence and potential impact on coastal infrastructure and maritime operations make them noteworthy. These moderate events are typically caused by weaker atmospheric fronts, localized thunderstorms, or internal atmospheric gravity waves. The variety of triggering mechanisms highlights the complexity of meteotsunami phenomena and underscores the necessity of maintaining continuous, high-resolution coastal monitoring networks. This study integrates empirical observations with numerical modeling to enhance the understanding of meteotsunami generation and amplification in the Southern Kuril Islands. The analysis confirms that rapidly propagating atmospheric pressure anomalies, especially those associated with intense cyclone activity, can induce significant sea-level responses through Proudman resonance when atmospheric disturbance speeds closely match the phase velocities of long oceanic waves over the shelf zone. The significant meteotsunami events in October 2011 and 2018 clearly illustrate this mechanism, exhibiting wave amplitudes comparable to those of moderate seismic tsunamis. Bay geometry, coastline orientation, and entrance characteristics critically influence wave amplification. East-facing and elongated bays such as Malokurilskaya, Krabovaya, and Dimitrova demonstrate pronounced resonance behavior, leading to persistent and substantial sea-level oscillations. Frequency-time diagrams and spectral analyses confirm the dominance of fundamental resonant modes and illustrate spatial variability in the responses among different locations. Moreover, weaker meteotsunamis not clearly linked to defined atmospheric fronts are associated with alternative atmospheric phenomena such as gravity waves or mesoscale pressure disturbances. These cases highlight the role of high-frequency atmospheric forcing and complex air-sea interactions, warranting further investigation. Numerical simulations using a modified, nested version of the TUNAMI-N2 model successfully captured the observed spatial and spectral characteristics of meteotsunami events. Despite simplifications in atmospheric forcing inputs and coupling schemes, the model reliably reproduced major resonance peaks, wave amplitudes, and event timing, thereby validating this modeling approach. The simulations further elucidated directional sensitivity and frequency-selective amplification, reinforcing the Proudman resonance mechanism's physical basis in meteotsunami dynamics. The identified directional sensitivity and localized amplification mechanisms emphasize the urgent need to integrate detailed bathymetric data and real-time atmospheric monitoring into existing tsunami early-warning systems. Such integration is vital not only for the Southern Kuril Islands but also for similar topographically complex coastal regions globally. Consequently, this study highlights the significance of combining in situ measurements with robust numerical modeling to evaluate and mitigate meteotsunami risks in tectonically and meteorologically active coastal areas. The findings advocate expanding coastal observation networks and refining coupled ocean-atmosphere modeling frameworks, essential for the timely detection and forecasting of meteotsunamis to safeguard maritime operations and support sustainable coastal development. Declarations Compliance with ethical standards Conflict of interest The authors declare that they have no competing interests. Acknowledgements We greatly appreciate the valuable comments and suggestions provided by Alexander Rabinovich (IORAS, Moscow, Russia) and Isaac Fine (IOS, Sidney, BC, Canada). This work was carried out with the support of the state research project FWWM-2024-0002 of the Institute of Marine Geology and Geophysics FEB RAS. References Brodtkorb AR, Sætra ML, Altinakar M (2012) Efficient shallow water simulations on GPUs: Implementation, visualization, verification, and validation. Comput Fluids 55:1–12. https://doi.org/10.1016/j.compfluid.2011.10.012 Giles M, Laszlo E, Reguly I, et al (2014) GPU Implementation of Finite Difference Solvers. In: 2014 Seventh Workshop on High Performance Computational Finance. IEEE, pp 1–8 Heidarzadeh M, Šepić J, Rabinovich A, et al (2020) Meteorological Tsunami of 19 March 2017 in the Persian Gulf: Observations and Analyses. 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Pure Appl Geophys 165:2169–2195. https://doi.org/10.1007/s00024-008-0426-5 Vilibić I, Monserrat S, Rabinovich AB (eds) (2015) Meteorological Tsunamis: The U.S. East Coast and Other Coastal Regions. Springer International Publishing, Cham Cite Share Download PDF Status: Published Journal Publication published 13 Mar, 2026 Read the published version in Natural Hazards → Version 1 posted Reviewers agreed at journal 20 Jul, 2025 Reviewers invited by journal 17 Jul, 2025 Editor assigned by journal 09 Jul, 2025 First submitted to journal 08 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7080527","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":486912413,"identity":"72c17c84-7577-479f-93c9-8027344f8037","order_by":0,"name":"Georgy Shevchenko","email":"","orcid":"","institution":"IMGG FEB RAS: Institut morskoj geologii i geofiziki DVO RAN","correspondingAuthor":false,"prefix":"","firstName":"Georgy","middleName":"","lastName":"Shevchenko","suffix":""},{"id":486912414,"identity":"780bb01b-cfc8-4090-97f0-e2646af106f0","order_by":1,"name":"Artem Loskutov","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAtklEQVRIiWNgGAWjYHACxgcMBQwMEkSr52FgYDZgMABpYSZeC5sEaVrs2bvTKn4Y2NhLzsg/+JiH4V5iA0FbeM5uu9ljkJY4WyKZ2ZiHoZgILRK5227wGBxOkJNIZpOcwZBAhBb5t9sK/xgctidBiwTvNmagLYxAh7FJfCBKy5nczdIyQL/M7HlsbPDBIMGYoBb29rMbP76psLGXOJ748EFCRYIsQS1owIBE9aNgFIyCUTAKsAMA0Og079A3Ae8AAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-1619-3671","institution":"IMGG FEB RAS: Institut morskoj geologii i geofiziki DVO RAN","correspondingAuthor":true,"prefix":"","firstName":"Artem","middleName":"","lastName":"Loskutov","suffix":""},{"id":486912415,"identity":"4bbe6003-2127-4fc4-8360-f5204c8ec8c8","order_by":2,"name":"Alexander Shishkin","email":"","orcid":"","institution":"IMGG FEB RAS: Institut morskoj geologii i geofiziki DVO RAN","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"","lastName":"Shishkin","suffix":""}],"badges":[],"createdAt":"2025-07-09 06:38:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7080527/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7080527/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11069-026-08060-6","type":"published","date":"2026-03-13T15:59:16+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":87315827,"identity":"03cc5472-60e7-4fdd-bb45-5c28d02b0ce7","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":663320,"visible":true,"origin":"","legend":"\u003cp\u003eThe location of IMGG BPRs in the Malokurilskaya, Krabovaya and Tserkovnaya bays (Shikotan Island) and in the Yuzhno-Kurilskaya Bay (Kunashir Island) and TWS gauge in the Kitovy bay (Kurilsk, Iturup Island)\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/d1dc59ed2dc9449c99d45473.png"},{"id":87315826,"identity":"e258d91a-71fe-43f8-ad2a-7fd30041b981","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":98180,"visible":true,"origin":"","legend":"\u003cp\u003eA 24-hour duration fragment of atmosphere pressure records obtained by digital weather stations at Yuzhno-Kurilsk, Kurilsk and by pressure gauge in Malokurilsk on October 15-16, 2011 (UTC time). On the right: spectral density plots of atmosphere pressure fluctuations at Malokurilsk calculated from a 5-hour time interval containing an atmospheric front starting at 11 p.m. October 15 (related to meteotsunami) and its previous one (background spectra)\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/f58c2f5c569450fb5336f4ed.png"},{"id":87315828,"identity":"f823d711-d2df-4d44-9e1b-dc829ac2401e","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1791471,"visible":true,"origin":"","legend":"\u003cp\u003eSpatial distribution of surface atmospheric pressure in the Northwest Pacific Ocean on October 15, 2011, at 9:28 UTC (left) and on October 16, 2011, at 2:57 (right)\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/97f60c2fb883ce6d96260c45.png"},{"id":87316880,"identity":"9f548803-b639-4595-b111-2b983b3006b2","added_by":"auto","created_at":"2025-07-22 16:01:05","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":267468,"visible":true,"origin":"","legend":"\u003cp\u003eShallow water long waves speed distribution map\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/40d3a7972f48ad16eff115d6.png"},{"id":87316878,"identity":"49339703-21c5-4ae1-8eb0-39b801ba6747","added_by":"auto","created_at":"2025-07-22 16:01:05","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":894562,"visible":true,"origin":"","legend":"\u003cp\u003eFragments of residual (de-tided) sea level records obtained by different gauges in the area of Southern Kuril Islands on October 15-16, 2011 (left plots, UTC time) and their frequency-time diagrams\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/622c9b76b769411443ceee40.png"},{"id":87316882,"identity":"b611dc29-b37f-4579-a1a0-0a187c82e47f","added_by":"auto","created_at":"2025-07-22 16:01:05","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":284480,"visible":true,"origin":"","legend":"\u003cp\u003ePower spectra plots of sea level oscillations at different BPRs calculated from 17-hour time interval containing meteotsunami (starting at 22:00 UTC, October 15) and its previous one (background spectra)\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/19ccb8356193ffc36e5ed4f9.png"},{"id":87315833,"identity":"3d018991-804a-45de-a7ee-d494e3ae6cd5","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":86796,"visible":true,"origin":"","legend":"\u003cp\u003ePressure records at Malokurilsk and Kurilsk on September 30 – October 1, 2018\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/07a074c47293d1fa1e21e998.png"},{"id":87315834,"identity":"31ed9278-17f2-4117-ba14-dc8c52b6134e","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":1797040,"visible":true,"origin":"","legend":"\u003cp\u003eSpatial distribution of surface atmospheric pressure in the Northwest Pacific Ocean\u003c/p\u003e\n\u003cp\u003eon October 1, 2018, at 2:49 UTC (left) and at 9:02 UTC (right)\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/fd5edca5ec761994a59ace8b.png"},{"id":87315835,"identity":"399a72fe-19f8-43cd-8d87-b59f4efc4368","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":871973,"visible":true,"origin":"","legend":"\u003cp\u003eFragments of residual (de-tided) sea level records obtained by different gauges in the area of Southern Kuril Islands on October 1, 2018 (left plots, UTC time) and their frequency-time diagrams\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/e2facc780270c4d9ce2e3674.png"},{"id":87315838,"identity":"b14c931a-36a6-4411-b4bd-9c301a492662","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":300670,"visible":true,"origin":"","legend":"\u003cp\u003ePower spectra plots of sea level oscillations at different BPRs calculated from 12-hour time interval containing meteotsunami (starting at 0:00 UTC, October 1) and its previous one (background spectra)\u003c/p\u003e","description":"","filename":"image10.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/372cbd4b2961702e55ab40c1.png"},{"id":87316884,"identity":"6d4bcd1a-bc30-4094-b1ab-ae473516e28a","added_by":"auto","created_at":"2025-07-22 16:01:05","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":422655,"visible":true,"origin":"","legend":"\u003cp\u003eDaily duration fragment of residual (de-tided) sea level records obtained by IMGG BPRs in the Malokurilsk and Yuzhno-Kurilsk seaports on August 3-4, 2010 (UTC time)\u003c/p\u003e","description":"","filename":"image11.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/532ddb7b3193a39666e2f918.png"},{"id":87315840,"identity":"522e246e-1200-4af9-adcd-632065380627","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":138452,"visible":true,"origin":"","legend":"\u003cp\u003eSpectral density plots of sea level oscillations at BPRs in the Malokurilsk and Yuzhno-Kurilsk seaports calculated from 1-day time interval containing meteotsunami (starting at 8 p.m. August 3) and its previous one (background spectra)\u003c/p\u003e","description":"","filename":"image12.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/1a09e4fb033fd10e330f7f48.png"},{"id":87316892,"identity":"aa83ef56-e3c4-4ea3-814b-68a9513046ed","added_by":"auto","created_at":"2025-07-22 16:01:05","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":494457,"visible":true,"origin":"","legend":"\u003cp\u003eSynthetic atmospheric waves derived from observations of atmospheric pressure at Malokurilsk spot and snapshots of atmospheric depression passage at Malokurilsk at 3:45 after simulation start and northern part of Iturup at 5:45\u003c/p\u003e","description":"","filename":"image13.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/ebe2f922a452d8f211198343.png"},{"id":87318631,"identity":"f956a9ce-fd2c-47e4-8451-bcd1de5f7777","added_by":"auto","created_at":"2025-07-22 16:17:05","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":421343,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of modeled records and measured records for Shikotan and Kunashir stations and their spectra\u003c/p\u003e","description":"","filename":"image14.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/b436e695203c4221f6fc6488.png"},{"id":87315852,"identity":"d95f5cb0-3d5e-425d-ad95-3cee8a32967f","added_by":"auto","created_at":"2025-07-22 15:53:05","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":168098,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of modeled records and their spectra at entrance of the Malokurilskaya Bay (M1) and at the inner part of the bay (M2). Heatmaps of significant peak energy amplification due to directivity and speed are given below\u003c/p\u003e","description":"","filename":"image15.png","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/ac8e198195bba5b66aad5e91.png"},{"id":104739944,"identity":"ec66c9ef-3aa9-42d3-9302-f2ea6d0a0a4d","added_by":"auto","created_at":"2026-03-16 16:13:49","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":8711018,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7080527/v1/9f5581d8-ab92-4d10-b20c-6a7cf9f1510c.pdf"}],"financialInterests":"","formattedTitle":"Meteotsunamis in the area of the Southern Kuril Islands: observations and numerical modeling","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eFollowing the strong Simushir earthquake and associated tsunami of 15 November 2006, a network of bottom pressure recorders (BPRs) was deployed by the Institute of Marine Geology and Geophysics (IMGG), Yuzhno-Sakhalinsk, Russia, in bays and harbors of the Southern Kuril Islands, including offshore areas near Shikotan, Kunashir, and Iturup (Shevchenko et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2011a\u003c/span\u003e). With a view to discover the local resonant characteristics of various bays and harbors, we analyze long-term time series of background sea-level oscillations and estimate the topographic admittance functions for each site, using spectral methods. The deployed instruments recorded several tsunamis, including the 2007 and 2009 Kuril Islands (Simushir) events, as well as the 2009 Samoa, 2010 Chile, and 2011 Tohoku tsunamis (Shevchenko et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2011b\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2013\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2014b\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003ea\u003c/span\u003e). Fortunately, during these measurements several strong meteorological tsunamis were also detected. The analysis of these events constitutes the primary objective of the present study.\u003c/p\u003e\u003cp\u003eIn recent decades, considerable attention has been devoted to meteorological tsunamis in various oceanic regions. In particular, the Mediterranean Sea has emerged as a focus of research due to the abundance of bays with pronounced resonant characteristics and the frequent occurrence of intense atmospheric disturbances conducive to meteotsunami generation (Rabinovich and Monserrat \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Vilibić \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Monserrat et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Vilibić et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2008\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Thomson \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Šepić et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Ličer et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Heidarzadeh et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). These two factors\u0026mdash;resonant bay geometry and favorable atmospheric forcing\u0026mdash;are critical for the generation of hazardous sea-level oscillations in coastal areas hosting ports and other infrastructure. Similar topographic and meteorological conditions are characteristic of the Southern Kuril Islands, particularly Shikotan Island, which features numerous bays with pronounced resonant responses and is frequently affected by thunderstorms and fast-moving atmospheric fronts capable of triggering meteotsunamis (Rabinovich and Levyant \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Rabinovich \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Rabinovich and Monserrat \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1996\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). However, in this region, meteorological tsunamis have received considerably less scientific attention. Even though the IMGG has been conducting long-term monitoring of long-wave processes\u0026mdash;within the tsunami-period band\u0026mdash;on the shelf and in the bays of Shikotan Island using seafloor pressure recorders (both cable-connected and autonomous), these phenomena remain underexplored. This relative lack of attention is likely due to the predominance of seismic tsunamis in the region, which pose a significantly greater hazard to coastal settlements along the Southern Kuril Islands.\u003c/p\u003e\u003cp\u003eThe continental slope adjacent to the Southern Kuril Islands corresponding to the western flank of the Kuril deep-sea trench is among the most seismically active regions in the world. Large magnitude, tsunamigenic undersea earthquakes are frequently observed in this area. In addition, hazardous waves have often been recorded during remote tsunamis generated by major subduction-zone earthquakes off the eastern coast of Japan and the coast of Chile (Shevchenko et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2011a\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2014b\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2017\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In contrast, relatively few studies have focused on meteorological tsunamis in the Southern Kuril Islands. One of the earliest documented cases appears in the monograph (Rabinovich \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1993\u003c/span\u003e), which describes a sharp intensification of seiche oscillations in Krabovaya, Otradnaya, and Malokurilskaya Bays on 8 May 1991 during the passage of a thunderstorm front. This event, along with two others occurring around the same time, was analyzed in more detail by (Rabinovich and Monserrat \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). A particularly rare and noteworthy case, in which meteotsunamis were not associated with resonance inside a bay but rather with a group of edge waves propagating along the Pacific coast of Shikotan Island, was described by (Litvin et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). This event was recorded in September 1989 by three seafloor pressure stations located on the shelf.\u003c/p\u003e\u003cp\u003eA couple of relatively weak meteorological tsunamis along with weak seismic tsunamis were considered in (Shevchenko et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2011a\u003c/span\u003e). A more significant event caused by the passage of an atmospheric front along the Lesser Kuril Ridge was briefly analyzed in (Kovalev et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In that study, both autonomous bottom pressure recorders (BPRs) operated by IMGG and telemetric tsunami sensors maintained by the Roshydromet Tsunami Warning Service (TWS) were utilized. This meteotsunami event is examined in greater detail in the following sections.\u003c/p\u003e\u003cp\u003eThe meteotsunami with the highest wave height recorded on October 1, 2018, in Dimitrova Bay on the ocean coast of Shikotan Island had a similar generation mechanism. The identity of the mechanisms of generation of the two most dangerous events prompted us to perform numerical modeling of the response in the Southern Kuril Strait and on the Pacific shelf of the Lesser Kuril Ridge to a rapidly moving atmospheric front. The results of the analysis of observational data and numerical modeling are presented below, and two weaker events unrelated to atmospheric fronts are also briefly considered. One of them was caused by a severe thunderstorm, the other was probably caused by internal gravitational waves in the atmosphere.\u003c/p\u003e"},{"header":"2 Meteotsunami on October 16, 2011","content":"\u003cp\u003eThe Meteotsunami of October 16, 2011, was recorded by IMGG BPRs in 3 bays of Shikotan Island: Tserkovnaya Bay on the Pacific coast and Krabovaya Inlet and Malokurilskaya Bay on the coast of Yuzhno-Kurilsky Strait (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Two BPRs were installed in the Malokurilskaya Bay - one of them in the inner area and another one outside (near the entrance). The fifth gauge was installed in the Yuzhno-Kurilsk seaport (Yuzhno-Kurilskaya Bay, Kunashir Island). Meteotsunami was also detected by TWS recorder which located in Kurilsk seaport (Kitovy Bay, Okhotsk Sea coast of Iturup Island).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSurface atmospheric pressure was measured using digital weather stations installed in Yuzhno-Kurilsk and Kurilsk settlements in autumn 2010. These stations were equipped with high-sensitive barographs recording at temporal resolution of 1 minute, which was well suited for analyzing the atmospheric disturbances responsible for meteotsunami generation. In addition, a bottom pressure recorder kept in the IMGG laboratory in Malokurilsk was activated for testing purposes and also recorded atmospheric pressure variations. In this situation the seafloor recorder was positioned on a high hill, thus observing lower absolute pressure values compared to the other stations. However, no altitude correction was applied, as only the relative pressure variations were of interest in this study.\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents atmospheric pressure records obtained during a 24-hour period on October 15\u0026ndash;16, 2011. A notable rapid drop in atmospheric pressure\u0026mdash;from 995.6 to 990 mbar within less than one hour\u0026mdash;was recorded by the Malokurilsk bottom gauge. At Yuzhno-Kurilsk, the minimum pressure (996.8 mbar) coincided in time with a local maximum at Malokurilsk. The pressure decrease recorded at the Kurilsk station was more pronounced (from 1002.5 to 995.0 mbar) but occurred over approximately two hours. Moreover, the pressure minimum at Kurilsk was observed about 50 minutes later than at Malokurilsk and approximately 105 minutes later than at Yuzhno-Kurilsk. No periodic atmospheric pressure oscillations, the typical pattern of internal gravity waves, which can sometimes be generated by atmospheric disturbances, were identified either before or after the passage of the front. Small-amplitude, high-frequency pressure fluctuations were observed only at the Malokurilsk gauge and were not detected by the other stations. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e on the right shows the spectral density plots calculated from 5-hour time interval containing an atmospheric front starting at 11 p.m. of October 15 (related to meteotsunami) and its previous one (background spectra) at Malokurilsk. The calculation was carried out on 2-hour segments with half shifts; the number of freedom degrees equals 8. The passage of the atmospheric front caused a significant (about an order of magnitude) increase in the energy of atmospheric pressure fluctuations at periods of 2.5 to 12 minutes. This increase was relatively uniform, with no pronounced peaks in the spectrum. We found a less significant effect found on periods of up to 2 hours. In a sense, this increase compared with ordinary meteorological conditions can be considered as the spectrum of the meteotsunami source for Shikotan Island. The increase in the energy of pressure fluctuations was smaller at other stations where the atmospheric front was weaker expressed.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAn approximate calculation indicated that the atmospheric front moved eastward at a speed of about 100 km/h. Comparable estimates of the cyclone velocity\u0026mdash;with a central pressure around 1000 hPa\u0026mdash;and its associated atmospheric fronts were obtained using surface atmospheric pressure maps available from an open-access website (NOAA \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Notably, while atmospheric disturbances propagated at approximately 100 km/h in the southern part of the Kuril Islands, their speed decreased to about 50 km/h in the central part of the Kuril Ridge. The propagation speeds of atmospheric fronts in the vicinity of the Southern Kuril Islands closely matched the phase velocities of long waves in the coastal region (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). In particular, the long-wave propagation speeds from both the southeastern and northwestern directions towards Shikotan Island are near 100 km/h. This condition is especially significant for efficient generation of intense oscillations within the bays of the island, a conclusion corroborated by the numerical modeling results presented below.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eDe-tided sea-level records obtained on October 15\u0026ndash;16, 2011 (covering a one-day interval) from the bays of Shikotan Island and the seaports of Yuzhno-Kurilsk and Kurilsk are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. In Krabovaya and Malokurilskaya Bays\u0026mdash;both at the inner site and near the bay entrance\u0026mdash;the onset of the meteotsunami is clearly identifiable, beginning at 01:28, nearly coinciding with the passage of the atmospheric pressure minimum over Shikotan Island. Sea-level oscillations associated with the meteotsunami persisted for approximately 10 hours.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIdentifying the onset of the meteotsunami in Tserkovnaya Bay and Yuzhno-Kurilskaya Bay proved somewhat more challenging. On the Pacific coast of Shikotan Island (Tserkovnaya Bay), the meteotsunami likely began approximately 6 minutes later than in Krabovaya Bay, whereas in Yuzhno-Kurilsk the onset was observed around 10 minutes earlier. The amplitudes of sea-level oscillations in these bays were significantly smaller. At the Kurilsk seaport, the meteotsunami appeared as high-frequency, small-amplitude fluctuations. Statistical characteristics of the meteotsunami\u0026mdash;such as trough-to-crest wave heights and arrival times of the first and maximum waves\u0026mdash;were not evaluated for this station but for the other sites provided in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eStatistical characteristics of meteotsunami on October 16, 2011, from the bottom pressure gauges on the Pacific coast of Russia\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eStation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eFirst wave\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003eMaximum wave\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHeight (cm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eArrival time\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eHeight (cm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eArrival time\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eYuzhno-Kurilsk\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e14.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e4:18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrough\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-10.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e4:31\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eTserkovnaya\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-1.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e25.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3:35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrough\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-10.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-16.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3:43\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMalokurilskaya (Out)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-15.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1:36\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrough\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-15.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e13.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1:46\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMalokurilskaya (In)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e37.2\u0026ndash;40.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1:47\u0026thinsp;\u0026minus;\u0026thinsp;2:21\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrough\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-27.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-37.3-32.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1:56\u0026thinsp;\u0026minus;\u0026thinsp;2:29\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eKrabovaya\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCrest\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e25.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e2:18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrough\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-30.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1:17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-24.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e2:37\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eOverall, the initial waves of the meteotsunami were recorded at all stations nearly simultaneously with the passage of the atmospheric front, supporting the interpretation of a common generation mechanism. The near-synchronous onset of oscillations both at the entrance and in the inner part of Malokurilskaya Bay is of particular interest. The maximum wave heights, their arrival times, and the durations of meteotsunami-induced oscillations varied among the bays, primarily due to differences in local resonance characteristics governed by bathymetry. This variability is most clearly illustrated in the frequency\u0026ndash;time diagrams presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. In bays with pronounced resonant properties\u0026mdash;specifically Malokurilskaya and Krabovaya Bays\u0026mdash;well-defined energy bands are observed, although at different frequencies. In contrast, in Yuzhno-Kurilskaya Bay, where resonance is weakly expressed, the spectral energy is more broadly distributed across a range of frequencies.\u003c/p\u003e\u003cp\u003eThe most pronounced sea-level oscillations were observed in Malokurilskaya Bay, which is known for its strong resonant response characteristics (Rabinovich and Levyant \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1992\u003c/span\u003e). The most hazardous wave group consisted of six oscillations, with trough-to-crest heights exceeding 50 cm. Such waves could pose a threat to vessels anchored within the bay and generate strong currents in the channel connecting the bay to the Pacific Ocean, potentially hindering vessel navigation. Two additional wave groups, with trough-to-crest heights ranging from 25 to 30 cm, were recorded during other time intervals. Overall, the pattern of sea-level oscillations during the meteotsunami resembled that observed during moderate seismic tsunamis in the bays of the Southern Kuril Islands (Shevchenko et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2011a\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In contrast, the meteotsunami posed a lower hazard to the seaports located in Krabovaya, Yuzhno-Kurilskaya, and Kitovy Bays. In Krabovaya Inlet, maximum wave heights reached 50 cm, while in the other bays the amplitudes were smaller.\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e shows spectral density plots calculated from 17-hour segments of de-tided sea-level records that include the meteotsunami event (beginning at 22:00 UTC on October 15) as well as the preceding interval used to compute background spectra. The analysis was performed for multiple bays of the Southern Kuril Islands. At all stations, spectral energy increased across a broad frequency band corresponding to wave periods between 2 and 100 minutes. In Tserkovnaya Bay, meteotsunami-induced oscillations spanned a wide range of periods; however, the most pronounced increase in spectral density was observed in the 5\u0026ndash;20-minute band\u0026mdash;close to the dominant zero-mode resonance period of the bay\u0026mdash;as well as at a longer period near 50 minutes. The spectral peak near 50 minutes does not correspond to any known resonant mode of the bay itself and is likely associated with the resonant characteristics of the adjacent shelf zone. A similar spectral feature was observed in 1991 during a meteotsunami event recorded on the oceanic shelf of Shikotan Island (Litvin et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2000\u003c/span\u003e), suggesting a broader regional origin for this component.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn the spectrum of sea-level oscillations recorded near the entrance to Malokurilskaya Bay\u0026mdash;both during the meteotsunami event and under calm conditions\u0026mdash;a well-defined peak was identified at a period of approximately 17.5 minutes. This spectral feature corresponds to the bay\u0026rsquo;s fundamental (zero-mode) resonance, characterized by a nodal line near the bay entrance. The presence of oscillatory energy at this location is therefore consistent with the expected spatial distribution of this mode. A second, more intriguing spectral peak was observed at a period of approximately 5.5 minutes, which was absent in the spectrum from the bay\u0026rsquo;s inner region. The physical origin of this shorter-period component remains unclear and warrants further investigation.\u003c/p\u003e\u003cp\u003eAt the station located in the inner part of Malokurilskaya Bay, spectral peaks at periods of approximately 17.5, 4.5, and 3 minutes\u0026mdash;corresponding to the natural resonant modes of the bay\u0026mdash;were clearly identified in both the meteotsunami and background segments. Notably, for the two higher-frequency peaks, the increase in spectral energy during the meteotsunami was minimal, significantly lower than the energy growth observed at other frequencies.\u003c/p\u003e\u003cp\u003eIn Krabovaya Bay, both the meteotsunami and background spectra exhibit a strong, well-defined peak at a period of approximately 30 minutes, which corresponds to the bay\u0026rsquo;s fundamental (zero-mode) resonance. The geometry of Krabovaya Bay\u0026mdash;characterized as a classic fjord, i.e., a narrow, elongated, and deep embayment with a relatively wide mouth\u0026mdash;favors amplification of the primary resonant mode toward the head of the bay, where the seaport and bottom pressure recorder were located.\u003c/p\u003e\u003cp\u003eIn the spectral analysis of Yuzhno-Kurilskaya Bay, the most significant increases in energy were observed at periods of approximately 25 minutes (associated with the bay\u0026rsquo;s resonant mode) and 45 minutes. The latter is likely related to the natural oscillation period of the Yuzhno-Kurilsky Strait, in agreement with previous estimates by (Rabinovich \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). In contrast, spectral energy at the Kurilsk seaport increased only in the high-frequency range, specifically in the 2\u0026ndash;6-minute band.\u003c/p\u003e\u003cp\u003eThe approach proposed in (Rabinovich \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1997\u003c/span\u003e), which involves computing the ratio of tsunami to background spectra provides a means of minimizing the influence of local bathymetric features and isolating the spectral characteristics of the forcing mechanism. We applied this method to the October 16, 2011, meteotsunami in the region of the Southern Kuril Islands. The resulting spectral ratios reveal a broad and relatively uniform increase in sea-level oscillation energy over the 5\u0026ndash;60-minute period band at all stations, except for Kurilsk. No distinct spectral peaks were detected at any location, suggesting the absence of localized resonant amplification within this range. Overall, the pattern of energy amplification in the sea-level spectra closely resembles the spectral enhancement observed in atmospheric pressure fluctuations at Malokurilsk during the passage of the atmospheric front. For shorter periods (\u0026lt;\u0026thinsp;5 minutes), the increase in spectral energy was significantly weaker. A similar broadband amplification pattern was reported for the 2010 Chilean tsunami, although that event also exhibited enhanced energy at lower frequencies (Shevchenko et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWe also analyzed the sea-level record obtained from the deep-ocean DART 21401 gauge, located in the region adjacent to the Southern Kuril Islands. Visual inspection of the de-tided time series for October 16 did not reveal any apparent amplification of oscillations. However, the frequency\u0026ndash;time diagram for October 15\u0026ndash;16 exhibited a noticeable increase in spectral energy between 1500 and 2000 minutes from the start of the record. This amplification occurred within the 5\u0026ndash;50-minute period band, which is consistent with the spectral characteristics observed at coastal stations. Nonetheless, in the open ocean, the magnitude of these oscillations was small, with the maximum spectral amplitude not exceeding 1.6 mm. This example highlights the predominantly local nature of meteotsunamis and their strong dependence on the resonant properties of coastal bays and the adjacent shelf zone\u0026mdash;an observation that aligns with the established understanding of meteotsunami dynamics (Rabinovich and Šepić \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e"},{"header":"3 Meteotsunami on October 1, 2018","content":"\u003cp\u003eThe characteristic surface atmospheric pressure variations were measured at the hydrophysical observatory on Shikotan Island (uncorrected to sea level) and by a digital weather station operated by the Kurilsk Hydrometeorological Service (HMS) on Iturup Island on September 30 \u0026ndash; October 1, 2018. Figure \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e represents the time series of recorded pressure disturbances. The pressure drop during the cyclone\u0026rsquo;s passage over Shikotan Island was only slightly greater\u0026mdash;by several hPa\u0026mdash;than that recorded on Iturup Island, despite the latter likely being farther from the cyclone center. However, the pressure change associated with the passage of the atmospheric front was considerably more abrupt: pressure at the observatory dropped by 7 hPa within 10 minutes and returned to its original level over the following 10 minutes. A similar, though less intense, pattern was observed at the Kurilsk station, where atmospheric pressure fell by 3 hPa and recovered within a comparable timeframe.\u003c/p\u003e\n\u003cp\u003eAs it shown in weather maps on Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e, at 2:49 UTC, a deep cyclone\u0026mdash;with a central pressure of 973 hPa\u0026mdash;was located southeast of Hokkaido Island, near the city of Kushiro. The cyclone was associated with both warm and cold fronts. By 09:02 UTC, the cyclone\u0026rsquo;s center had shifted to a position offshore of Urup Island, having traveled approximately 600 km in six hours. This corresponds to an average propagation speed of ~\u0026thinsp;100 km/h for the atmospheric disturbance and its associated frontal structures.\u003c/p\u003e\n\u003cp\u003eThe time interval between the pressure minima at the two stations was exactly one hour. The straight-line distance between the stations is approximately 130 km, while the distance measured along the cyclone\u0026rsquo;s estimated trajectory is about 115 km. Based on this, the speed of the atmospheric disturbance is estimated at approximately 115 km/h\u0026mdash;a value likely more reliable than estimates derived from surface pressure map analysis alone. This suggests that the cyclone accelerated significantly\u0026mdash;by a factor of about 1.5\u0026mdash;as it approached the Southern Kuril Islands compared to its earlier trajectory along Hokkaido Island.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e presents 12-hour segments of de-tided sea-level recorded on October 1, 2018, at the Kushiro and Hanasaki stations (Japan), as well as in Yuzhno-Kurilskaya, Otradnaya, Malokurilskaya, and Dimitrova Bays (the Southern Kuril Islands), along with their corresponding frequency\u0026ndash;time diagrams. Statistical characteristics of the meteotsunami event\u0026mdash;including trough-to-crest wave heights and the arrival times of the first and maximum waves\u0026mdash;are summarized in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003eThe initial high-amplitude waves were recorded at Kushiro station. Although it is difficult to unambiguously determine the exact onset time of the meteotsunami in the time series, it can be inferred from the frequency\u0026ndash;time diagram by a shift in the dominant frequency content. Specifically, the meteotsunami induced lower-frequency oscillations compared to background conditions, a pattern that is clearly evident in the diagram. These relatively long-period oscillations, with a dominant period of approximately 30 minutes, persisted for nearly 8 hours and are attributed to the meteotsunami.\u003c/p\u003e\n\u003cp\u003eSubsequently, the character of the wave field changed markedly, returning to its typical state in which high-frequency components again dominated the sea-level variability. This transition is clearly visible in the frequency\u0026ndash;time diagram, where the band of spectral maxima shifted abruptly from approximately 0.03 cycles per minute to 0.2 cycles per minute. The maximum wave\u0026mdash;exhibiting a trough-to-crest height of 70 cm\u0026mdash;was recorded about 1.5 hours earlier than in the port of Hanasaki, where the meteotsunami posed a more serious hazard, with a maximum wave height of 110 cm.\u003c/p\u003e\n\u003cp\u003eThe structure of sea-level oscillations at Hanasaki was similar to that observed at Kushiro station: a weak leading wave, followed by a high-amplitude wave, and then a series of long-lasting, slowly decaying oscillations with dominant frequencies lower than the background variability. Given the approximate distance of 110 km between the stations, the velocity of the atmospheric disturbance responsible for the anomalous oscillations can be estimated at around 75 km/h. According to the frequency\u0026ndash;time diagram, the main energy of the meteotsunami was concentrated in the 0.05\u0026ndash;0.06 cycles per minute range, corresponding to a dominant period of ~\u0026thinsp;18 minutes\u0026mdash;likely associated with a resonant mode of Hanasaki Bay. A secondary contribution was observed at a period of approximately 35 minutes. The decay of oscillation amplitude at Hanasaki was slightly slower than at Kushiro, although the total duration of the event at both locations was approximately 8 hours.\u003c/p\u003e\n\u003cp\u003eThe meteotsunami was also recorded on the Pacific coast of Shikotan Island by a bottom pressure recorder (BPR) deployed in Dimitrova Bay, located approximately 115 km from the Hanasaki station. In this location, the nature of the wave process differed somewhat from that observed at the Japanese stations and was more typical of bays exhibiting stable resonant behavior. Instead of a single dominant wave, a wave group with the highest amplitude concentrated near the center was observed. The maximum recorded trough-to-crest wave height reached 188 cm, representing the largest meteotsunami ever observed along the coast of the Kuril Ridge\u0026mdash;and, more broadly, in the entire Russian Far East. This wave height is comparable to that produced by moderate-intensity seismic tsunamis, typically defined as events with amplitudes on the order of 2 m. Such waves pose a tangible hazard to vessels and coastal infrastructure located in nearshore zones. However, this event occurred on the uninhabited Pacific coast of Shikotan Island, where no permanent settlements currently exist.\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eStatistical characteristics of meteotsunami on October 1, 2018, from the bottom pressure gauges on the Pacific coast of Russia and Japan\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eStation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eFirst wave\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eMaximum wave\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHeight (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eArrival time\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHeight (cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eArrival time\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eKushiro\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCrest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0:42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1:27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTrough\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0:51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026minus;17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1:44\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eHanasaki\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCrest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2:11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2:59\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTrough\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026minus;32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eDimitrova\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCrest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4:05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTrough\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2:54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026minus;92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4:15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eMalokurilskaya\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCrest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5:16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTrough\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026minus;61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5:26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eOtradnaya\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCrest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:58\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTrough\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026minus;34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026minus;34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eYuzhno-Kurilsk\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCrest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4:25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTrough\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3:17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4:44\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003eIn the frequency\u0026ndash;time diagram, a broad energy patch is visible at the beginning of the record, indicating the onset of a meteotsunami in the frequency range of 0.04\u0026ndash;0.08 cpm, with nearly uniform intensity across this band. The maximum spectral amplitude within this interval reached approximately 40 cm. Subsequently, a narrow, persistent energy band appears at ~\u0026thinsp;0.06 cpm (corresponding to a period of ~\u0026thinsp;16 minutes), which reflects the dominant resonant mode of Dimitrova Bay.\u003c/p\u003e\n\u003cp\u003eThe most prominent oscillations spanned the time interval from approximately 03:00 to 12:00 local time\u0026mdash;about one hour longer than the duration observed at the Japanese stations. This extended duration is likely attributed to the more pronounced resonant characteristics of Dimitrova Bay, which typically enhance both the persistence and amplitude of long-wave oscillations.\u003c/p\u003e\n\u003cp\u003eLet us now consider the records obtained along the coast of the Southern Kuril Strait. In both Otradnaya Bay and Yuzhno-Kurilskaya Bay, the pattern of sea-level oscillations was generally similar and closely resembled that observed along the coast of Hokkaido\u0026mdash;characterized by an initial high-energy impulse followed by gradually decaying oscillations.\u003c/p\u003e\n\u003cp\u003eA notable feature of the wave process in Otradnaya Bay was the presence of a distinct initial negative displacement, which was immediately followed by a strong positive pulse reaching 57 cm in trough-to-crest height. On Kunashir Island, the oscillations began with relatively weak fluctuations but were followed\u0026mdash;approximately 30 minutes later than in Otradnaya Bay\u0026mdash;by a pronounced positive peak. The reason for this temporal offset between two geographically proximate locations remains unclear. In both bays, low-frequency oscillations persisted for approximately 11 hours, gradually decreasing in amplitude over time.\u003c/p\u003e\n\u003cp\u003eThe frequency\u0026ndash;time diagram for Otradnaya Bay reveals a broad spectral maximum during the initial phase of the record. The spectral energy was distributed relatively evenly across the 0.02\u0026ndash;0.05 cycles per minute (cpm) range, after which the dominant energy became concentrated within a narrower band between 0.03 and 0.04 cpm.\u003c/p\u003e\n\u003cp\u003eIn Yuzhno-Kurilskaya Bay, the spectral composition of the sea-level oscillations was more complex, with elevated energy observed across a wider frequency range from 0.02 to 0.08 cpm. This broadband response is characteristic of basins with relatively weak frequency-selective properties, where multiple modes may be excited simultaneously without a dominant resonant frequency.\u003c/p\u003e\n\u003cp\u003eIn Malokurilskaya Bay, where the fundamental (zero-mode) resonance with a period of approximately 19 minutes is persistently present in the sea-level records, it is particularly difficult to accurately determine the onset and termination of wave events\u0026mdash;whether tsunami or meteotsunami. Notably, as in Otradnaya Bay, located only a short distance away, the meteotsunami-induced oscillations began with a pronounced negative sea-level excursion exceeding 50 cm. The corresponding trough-to-crest wave height reached 86 cm.\u003c/p\u003e\n\u003cp\u003eThe event initially manifested as a wave group consisting of seven oscillations, within which the third wave was the smallest in amplitude, while the sixth was the largest.\u003c/p\u003e\n\u003cp\u003eAn additional four wave groups associated with the meteotsunami were identified in the Malokurilskaya Bay record, with amplitudes gradually decreasing over time. The final group was observed between 18:30 and 22:30 UTC and exhibited a maximum trough-to-crest wave height of 34 cm\u0026mdash;still a substantial value in the context of non-seismic sea-level disturbances. The dominant oscillation energy was concentrated within a narrow frequency band ranging from 0.05 to 0.07 cycles per minute (cpm), except during the initial phase, when lower-frequency oscillations (~\u0026thinsp;0.04 cpm) were also present.\u003c/p\u003e\n\u003cp\u003eThe Fig. \u003cspan class=\"InternalRef\"\u003e10\u003c/span\u003e additionally shows comparative spectral analyses of sea-level oscillations recorded during the meteotsunami and corresponding background noise.\u003c/p\u003e\n\u003cp\u003eAt Dimitrova Bay, spectral peaks during the meteotsunami event prominently appear at periods of approximately 16.4, 7.8, 5.8, and 3.1 minutes, significantly exceeding background energy levels. Such multiple spectral peaks suggest resonance patterns characteristic of the bay\u0026apos;s basin complex geometry.\u003c/p\u003e\n\u003cp\u003eMalokurilskaya Bay displays notable energy peaks at approximately 17.5, 4.1, and 3.1 minutes, also markedly elevated above background conditions. The dominant peak at 17.5 minutes likely corresponds to the fundamental resonant mode of the bay, whereas shorter-period peaks indicate higher-order resonance effects.\u003c/p\u003e\n\u003cp\u003eIn Otradnaya Bay, the spectral analysis identifies a clear dominant energy peak around 30 minutes, substantially above the background, indicative of a single dominant resonance mode in this locality during meteotsunami events.\u003c/p\u003e\n\u003cp\u003eAt Yuzhno-Kurilskaya Bay, a similar pattern emerges with a pronounced peak around a 27-minute period. This suggests that the bay\u0026apos;s resonant characteristics concentrate wave energy within a narrower frequency band, enhancing local impacts during meteotsunami occurrences.\u003c/p\u003e\n\u003cp\u003eThe station at Hanasaki reveals a distinct bimodal spectral structure with peaks at approximately 22.5 and 8.6 minutes. Both peaks significantly exceed the 95% confidence threshold, emphasizing their statistical significance over background fluctuations.\u003c/p\u003e\n\u003cp\u003eLastly, Kushiro station exhibits a notable energy peak at approximately 30 minutes, with additional minor yet statistically meaningful peaks observed at 12.9 and 5.1 minutes. These multiple peaks indicate complex spectral responses likely associated with local bathymetric or coastal geometrical features.\u003c/p\u003e\n\u003cp\u003eCollectively, the spectral characteristics outlined above underscore the site-specific resonant responses of coastal locations to meteotsunami forcing, highlighting the importance of detailed local bathymetric and morphological analyses.\u003c/p\u003e"},{"header":"4 Other examples of meteotsunami recording in the Southern Kuril Islands","content":"\u003cp\u003e\u003cem\u003eAugust 3\u0026ndash;4, 2010.\u003c/em\u003e Another meteotsunami event was recorded in Malokurilskaya and Yuzhno-Kurilskaya Bays on August 3\u0026ndash;4, 2010, with maximum trough-to-crest wave heights of 42 cm and 39 cm, respectively (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e11\u003c/span\u003e). The anomalous sea-level oscillations were associated with a severe thunderstorm that also caused an electric power blackout across the Southern Kuril Islands. Unfortunately, no digital atmospheric pressure measurements were available for this event, and therefore the exact characteristics of the pressure fluctuations associated with the thunderstorm remain unknown.\u003c/p\u003e\n\u003cp\u003eThe sea-level response was particularly unusual, especially in Yuzhno-Kurilskaya Bay. This bay is generally characterized by weak resonant properties and typically exhibits a much lower response to external atmospheric forcing compared to Malokurilskaya Bay, which displays strong resonant amplification. However, during this meteotsunami event, the responses in both bays were of comparable amplitude.\u003c/p\u003e\n\u003cp\u003eSpectral density analysis of sea-level fluctuations during the event (Fig. \u003cspan class=\"InternalRef\"\u003e12\u003c/span\u003e) showed a relatively uniform increase in energy over a broad period range from 4 to 60 minutes. No distinct spectral peak was observed at any specific frequency in Yuzhno-Kurilskaya Bay, suggesting a non-resonant response\u0026mdash;an atypical feature for meteotsunami-related sea-level disturbances. In Malokurilskaya Bay, the most significant energy increase occurred within the 25\u0026ndash;60-minute period range, while the response at the known resonance periods of 4.5 and 19 minutes was notably weaker. This indicates that the sea-level response in this bay to the passing thunderstorm was also highly unusual and did not follow the typical resonance-dominated pattern.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOctober 6\u0026ndash;7, 2018.\u003c/em\u003e Another meteotsunami event, more precisely, two successive events within a single day\u0026mdash;was recorded one week after the strongest meteotsunami on October 1, 2018. Although significantly weaker, well-defined sea-level oscillations were observed in several bays of Shikotan Island. Sea-level records obtained from bottom pressure recorders (BPRs) in Otradnaya, Dimitrova, and Malokurilskaya Bays, were obtained.\u003c/p\u003e\n\u003cp\u003eIn Dimitrova Bay, wave groups with a dominant period of ~\u0026thinsp;16 minutes\u0026mdash;associated with the bay\u0026rsquo;s zero-mode resonance\u0026mdash;were consistently present. Two distinct episodes of amplitude amplification were identified. The second group, observed between 04:52 and 10:16 UTC on October 7, was more intense, with a mean amplitude of ~\u0026thinsp;12 cm, although its duration was about an hour shorter than the first. The first group was less distinguishable in the frequency\u0026ndash;time diagram, marked primarily by sustained elevated spectral amplitudes near the 16-minute band. In contrast, the second event was clearly characterized by the appearance of additional spectral bands at ~\u0026thinsp;0.05 and 0.03 cycles per minute (cpm).\u003c/p\u003e\n\u003cp\u003eIn Otradnaya Bay, initial oscillations were irregular and of low amplitude. However, around 20:00 UTC on October 6, the wave regime shifted abruptly, giving rise to regular oscillations with dominant periods between 20 and 25 minutes. These persisted through the night. At the onset of this group, a maximum wave of 32 cm was recorded, followed by stable-amplitude oscillations (~\u0026thinsp;11 cm). Several hours later, at 05:11 UTC, another shift occurred, associated with the arrival of a distinct wave group. The leading wave in this group had a trough-to-crest height of 30 cm and was followed by four gradually decaying oscillations with slightly longer periods (~\u0026thinsp;30 minutes).\u003c/p\u003e\n\u003cp\u003eThe strongest oscillations were recorded in Malokurilskaya Bay. As previously noted, this bay is characterized by persistent zero-mode resonance at ~\u0026thinsp;19 minutes, which makes identifying the precise onset of a meteotsunami challenging. The event likely began around 20:00 UTC on October 6, coinciding with a marked increase in wave amplitude. A group of seven waves followed, with an average amplitude slightly exceeding 20 cm, the fourth wave being the largest. After a period of energy decay, a second group consisting of twelve lower-amplitude (~\u0026thinsp;10 cm) oscillations were recorded. Later, as in Otradnaya Bay, a final group of four gradually decaying waves was observed.\u003c/p\u003e\n\u003cp\u003eIn contrast, the meteotsunami signals recorded in Yuzhno-Kurilskaya Bay, as well as at the Japanese coastal stations in Kushiro and Hanasaki, were negligible and are not analyzed further.\u003c/p\u003e\n\u003cp\u003eA synoptic map of surface atmospheric pressure (not shown) indicates that the cyclone and its associated frontal system, unlike the event of October 1, followed a trajectory directed toward the open Pacific rather than along the Kuril Island arc. Such a cyclone track deviates from the classical meteotsunami generation mechanism involving a coherent atmospheric front propagating along the island chain, as commonly simulated in numerical models.\u003c/p\u003e\n\u003cp\u003eThis interpretation is supported by surface atmospheric pressure records from the Shikotan geophysical observatory (GFO) and the Kurilsk HMS. On Shikotan Island, two distinct intervals of intense pressure fluctuations were recorded: from 17:00 to 23:00 UTC on October 6 (associated with the cyclone\u0026rsquo;s leading front), and from 03:00 to 07:00 UTC on October 7 (corresponding to the passage of the cyclone center). At Kurilsk station, the cyclone\u0026rsquo;s influence was weaker, and no clear frontal passage was observed. Nevertheless, both stations registered an elevated atmospheric pressure variability starting at approximately 17:00 UTC on October 6 and continuing until 09:00 UTC on October 7, though with different amplitudes and patterns.\u003c/p\u003e\n\u003cp\u003eThe mechanism responsible for the generation of the observed long-period oscillations in several bays\u0026mdash;interpreted here as meteotsunamis\u0026mdash;appears fundamentally different from that of the stronger October 1 event. It is likely that the oscillations were driven by atmospheric pressure fluctuations within the tsunami frequency band, potentially caused by internal gravity waves in the atmosphere. However, this hypothesis cannot be confirmed definitively due to the limited availability of meteorological data.\u003c/p\u003e"},{"header":"5 Numerical Modeling and Analysis of Meteotsunami Events Near the Southern Kuril Islands","content":"\u003cp\u003eA numerical simulation of the strongest meteotsunami event of October 1\u0026ndash;2, 2018, was conducted to verify the generation mechanisms, amplification processes and estimate energy directivity. This event was selected due to its pronounced sea-level disturbances recorded by tide gauges and their clear correlation with atmospheric pressure anomalies as described above.\u003c/p\u003e\u003cp\u003eTo simulate the generation and resonant amplification of the meteotsunami, we employed a modified version of the GPU-accelerated shallow-water model TUNAMI-N2 (Imamura et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Brodtkorb et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Giles et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Oishi et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), widely used in tsunami studies. The model was adapted to incorporate dynamically evolving atmospheric pressure fields as a surface forcing mechanism, thereby enabling the simulation of pressure-induced wave generation and propagation.\u003c/p\u003e\u003cp\u003eThe computational domain setup was illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The outer grid encompasses the oceanic shelf surrounding the Southern Kuril Islands and serves as the primary domain for propagating long waves forced by the moving atmospheric disturbance. The domain spans from 143\u0026deg; 0\u0026prime; 22.54\u0026Prime; E to 149\u0026deg; 1\u0026prime; 37.49\u0026Prime; E longitude and from 41\u0026deg; 47\u0026prime; 43.57\u0026Prime; N to 45\u0026deg; 58\u0026prime; 7.58\u0026Prime; N latitude, with a resolution of 15 arcseconds (~\u0026thinsp;463 m) and grid dimensions of 1446 \u0026times; 1003 nodes. Bathymetric data were derived from high-resolution GEBCO datasets and refined using regional hydrographic surveys to improve topographic accuracy. Open boundaries were applied on all sides of the domain to allow outgoing wave energy to radiate freely, minimizing artificial reflections.\u003c/p\u003e\u003cp\u003eTo capture local resonant responses in individual bays and inlets, high-resolution nested grids were embedded within the outer model. Each nested domain was specifically designed to match the local bathymetry and was forced at the boundaries using interpolated sea-level data from the parent grid. The spatial parameters and configurations of the nested domains are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eGeometric characteristics of computational subdomains\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eName\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMalokurilskaya Bay\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTserkovnaya Bay\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eKrabovaya Inlet\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eDimitrova Bay\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eYuzhno-Kurilskaya Bay\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eGrid Size\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNx\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e205\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e162\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e207\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e412\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e326\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e133\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e121\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e134\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e177\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e243\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLongitudes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e146\u0026deg; 46\u0026prime; 19.7\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e146\u0026deg; 40\u0026prime; 37.99\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e146\u0026deg; 41\u0026prime; 51.0\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e146\u0026deg; 48\u0026prime; 14.04\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e145\u0026deg; 47\u0026prime; 16.08\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMax\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e146\u0026deg; 49\u0026prime; 43.9\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e146\u0026deg; 43\u0026prime; 18.98\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e146\u0026deg; 45\u0026prime; 17.03\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e146\u0026deg; 55\u0026prime; 5.02\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e145\u0026deg; 52\u0026prime; 41.3\u0026Prime; E\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLatitudes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e43\u0026deg; 51\u0026prime; 12.51\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e43\u0026deg; 42\u0026prime; 54.0\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e43\u0026deg; 48\u0026prime; 41.0\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e43\u0026deg; 46\u0026prime; 28.0\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e43\u0026deg; 58\u0026prime; 56.2\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMax\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e43\u0026deg; 53\u0026prime; 24.14\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e43\u0026deg; 44\u0026prime; 54.0\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e43\u0026deg; 50\u0026prime; 53.99\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e43\u0026deg; 49\u0026prime; 24.0\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e44\u0026deg; 2\u0026prime; 58.2\u0026Prime; N\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eResolution\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003edL\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c7\" namest=\"c3\"\u003e\u003cp\u003e~\u0026thinsp;30.7 m x 30.7 m\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eIdeally, accurate simulation of meteotsunami generation by a propagating atmospheric front requires high-resolution spatial data for the pressure field. However, even under optimal synoptic analysis conditions, the temporal resolution of available datasets is limited to one hour, which is insufficient for capturing the high-frequency dynamics of the processes investigated in this study. To construct a more temporally refined atmospheric forcing, we employed a high-resolution barometric pressure series obtained at Malokurilsk. This record was transformed into a spatial pressure field under the assumption that the atmospheric front propagated at a speed of ~\u0026thinsp;115 km/h at an azimuthal angle of approximately 60\u0026deg; from true north. This propagation scenario is consistent with the structure of the pressure fields observed in synoptic weather maps. The pressure time series was expanded spatially using the assumed front velocity and original temporal discretization. The resulting dynamic pressure anomaly containing sharp depression in the vicinity of pressure wave train head extended over ~\u0026thinsp;2,500 km and was interpolated into the numerical model as an external forcing mechanism (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e). The generated wave field in the outer domain (over the continental shelf of the southern Kuril Islands) was transmitted to nested coastal subdomains through boundary conditions applied at the interfaces.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe model did not include local atmospheric wave generation within the bays themselves. This simplification is justified by the relatively short residence time of the atmospheric front over these small basins, which is insufficient to induce significant meteotsunami generation. Instead, the simulation focused on the resonant response of the bays to the incoming pressure-forced long waves generated over the shelf.\u003c/p\u003e\u003cp\u003eThe total simulation time was 24 hours, with a time step of 250 milliseconds in the outer domain and 1 minute in the nested domains. Synthetic tide gauge records were extracted at key stations across all grids. Model results demonstrated good agreement with observations (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e), capturing key features of the meteotsunami\u0026mdash;including wave amplitudes and the spectral structure of resonant peaks.\u003c/p\u003e\u003cp\u003eSome limitations arise from the disparity in spatial resolution between the outer and nested grids, which reduced the model\u0026rsquo;s ability to resolve bidirectional energy exchange across domain boundaries. This simplification resulted in a continuous energy influx into the inner domains and gradual amplification of oscillations. However, this effect did not significantly affect the primary objective of the simulation: to evaluate resonance amplification and directional sensitivity of individual bays to atmospheric disturbances of varying trajectories and velocities.\u003c/p\u003e\u003cp\u003eIn the recent research (Rabinovich et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) patterns of directivity of meteotsunami maximum simulated height were examined. Here we focus on more detailed analysis of directivity of energy response for each significant resonant peak attached to lower frequency eigen mode excited by meteotsunami. Corresponding normalized to maximum spectral power heatmaps (Fig.\u0026nbsp;\u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e15\u003c/span\u003e) computed for nearshore virtual gauges revealed patterns of spatial selectivity. The figure illustrates a set of directional resonance diagrams for four observational sites\u0026mdash;Dimitrova, Malokurilskaya, Otradnaya, and Yuzhno-Kurilskaya bays\u0026mdash;situated in the Southern Kuril Islands region. Each panel represents a heatmap of spectral energy concentration at specific resonant periods as functions of azimuth and propagation speed of an atmospheric pressure disturbance. The intensity of coloration indicates the relative magnitude of the resonance, with darker shading corresponding to higher resonant spectral power.\u003c/p\u003e\u003cp\u003eIn Dimitrova Bay, significant resonance peaks appear at longer periods, specifically around 40 and 20 minutes, demonstrating clear directional preference at azimuths of approximately \u0026minus;\u0026thinsp;90\u0026deg; to -120\u0026deg;, with predominant atmospheric disturbance speeds of approximately 110\u0026ndash;130 km/h. The identified directional preference suggests a pronounced Proudman resonance mechanism where the atmospheric disturbance speed closely matches the local long-wave phase speed along the adjacent shelf, potentially further enhanced by shelf bathymetry aligned orthogonally to the observed azimuthal angles.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMalokurilskaya Bay exhibits prominent resonance at periods around 17.8 and 5 minutes, with the most pronounced directivity at approximately \u0026minus;\u0026thinsp;90\u0026deg; and \u0026minus;\u0026thinsp;240\u0026deg; azimuths and propagation speeds ranging predominantly between 100 and 130 km/h. The distinct resonance at these shorter periods implies a significant influence of local bathymetric features, suggesting a localized shelf resonance or harbor amplification, potentially intensified by Proudman resonance conditions due to atmospheric disturbances propagating at speeds coinciding closely with local wave speed.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eOtradnaya Bay demonstrates clear spectral resonance at longer periods (38 and 15 minutes) predominantly aligned along azimuth \u0026minus;\u0026thinsp;90\u0026deg;, suggesting strong sensitivity to pressure disturbances propagating nearly perpendicular to the shoreline. Additionally, intermediate resonances (10 min period) show broader azimuthal distribution with peak responses at several discrete azimuthal angles (-60\u0026deg;, -120\u0026deg;, -210\u0026deg;), indicating combined effects of local coastal topography and broader shelf resonance conditions.\u003c/p\u003e\u003cp\u003eFinally, Yuzhno-Kurilskaya Bay shows complex resonance patterns with pronounced energy peaks at multiple periods, notably around 23, 10.5, and 7 minutes. Resonances are directionally selective, predominantly aligned at azimuths near \u0026minus;\u0026thinsp;90\u0026deg; and \u0026minus;\u0026thinsp;120\u0026deg;, reflecting pronounced Proudman resonance effects possibly complemented by intricate interactions with the local bathymetric configuration. Resonant peaks occurring at shorter periods (5.3, 2.5 minutes) suggest additional harbor resonance mechanisms linked to highly localized topographical features within the bay.\u003c/p\u003e\u003cp\u003eOverall, these directional heatmaps underscore the interplay between atmospheric forcing characterized by specific speeds and propagation directions, shelf resonance influenced by coastal bathymetry, and localized topographic amplification within bays. The marked directional selectivity highlights the critical importance of Proudman resonance and emphasizes the necessity of integrating detailed bathymetric and atmospheric data when assessing meteotsunami hazards in coastal regions.\u003c/p\u003e"},{"header":"6 Discussion","content":"\u003cp\u003eThis study presents a comprehensive analysis of two significant meteotsunami events affecting the Southern Kuril Islands, integrating long-term sea-level observations with high-resolution numerical simulations. The findings clarify the dominant generation mechanisms\u0026mdash;particularly the role of Proudman resonance\u0026mdash;and highlight the influence of local bathymetry, coastline orientation, and atmospheric dynamics on meteotsunami amplification.\u003c/p\u003e\u003cp\u003eThe events of October 16, 2011, and October 1, 2018, represent two of the most energetic meteotsunamis observed in this region. Spectral analyses of de-tided sea-level data revealed pronounced amplification at distinct resonant frequencies, especially in Malokurilskaya, Krabovaya, and Dimitrova Bays. These peaks, frequently around 16\u0026ndash;20 minutes, correspond to the fundamental (zero) resonance modes and were further confirmed by frequency-time diagrams and power spectral density estimates. The concurrent presence of rapidly propagating atmospheric pressure anomalies supports the interpretation that Proudman resonance was the dominant mechanism.\u003c/p\u003e\u003cp\u003eProudman resonance arises when the speed of an atmospheric disturbance matches the phase speed of long gravity waves in the ocean. In both primary cases, atmospheric fronts moved eastward at speeds of approximately 100\u0026ndash;115 km/h, closely aligning with long-wave phase speeds over the 50\u0026ndash;200 m shelf region adjacent to the Kuril Islands. This velocity matching led to constructive interference, facilitating efficient energy transfer from the atmosphere to the ocean surface. The waveforms observed in resonant bays\u0026mdash;featuring coherent, long-duration oscillations with high wave amplitudes\u0026mdash;were accurately reproduced in the model simulations.\u003c/p\u003e\u003cp\u003eThe directionality of the atmospheric front relative to coastal orientation played a significant role in wave amplification. Bays aligned with the trajectory of the atmospheric front experienced greater resonance effects, particularly those with open east-facing configurations such as Malokurilskaya Bay. Spatial distributions of model-simulated wave energy revealed focused amplification patterns, strongly influenced by the bay geometry, entrance width, and depth profile.\u003c/p\u003e\u003cp\u003eHowever, the analysis also exposed cases of significant sea-level oscillations without clear association with traveling pressure fronts. The events of August 3\u0026ndash;4, 2010, and October 6\u0026ndash;7, 2018, likely involved alternative generation mechanisms such as internal atmospheric gravity waves or localized pressure perturbations caused by thunderstorms. These cases exhibited broader spectral content and different temporal evolution, suggesting excitation through high-frequency atmospheric forcing rather than classical resonance. Notably, spectral ratios between tsunami and background signals in these cases showed non-resonant amplification across a wide period range.\u003c/p\u003e\u003cp\u003eSuch findings underscore the multifactorial nature of the meteotsunami generation. While Proudman resonance often governs large-scale events, small-scale atmospheric disturbances can also induce significant responses in coastal basins with favorable topographic conditions. This emphasizes the necessity of dense, high-resolution atmospheric and oceanic monitoring to distinguish among potential mechanisms.\u003c/p\u003e\u003cp\u003eThe numerical modeling framework provided valuable insights into the wave generation and resonance processes. However, limitations remain. The atmospheric pressure forcing was reconstructed from a single time series, assuming uniform translation speed and direction\u0026mdash;neglecting spatial variability and synoptic-scale evolution. Furthermore, atmospheric wave dynamics, including dispersion and local convection, were not captured. The lack of two-way coupling between outer and nested domains introduced artificial energy buildup in some bays, while resolution mismatches hindered detailed wave focusing and dissipation patterns. Moreover, bathymetric smoothing at nesting boundaries may have compromised accurate wave transmission in complex geometries. These limitations suggest that while the simulations provide reliable first-order insights, further model refinement is necessary to fully capture the complex interactions governing meteotsunami dynamics.\u003c/p\u003e\u003cp\u003eNevertheless, validation against observational data yielded good agreement in wave amplitudes, timing, and spectral content, with correlation coefficients exceeding 0.85 and RMSE values under 3 cm. The model successfully reproduced key features of meteotsunami excitation and amplification, including the resonance-enhanced oscillations and direction-dependent energy transfer.\u003c/p\u003e"},{"header":"7 Conclusions","content":"\u003cp\u003eRegular sea-level observations conducted by the Institute of Marine Geology and Geophysics (IMGG) between 2007 and 2021, primarily in the bays of Shikotan Island, have provided critical insights into the recurrence patterns and intensities of meteotsunamis in the Southern Kuril Islands. These long-term observations reveal that significant meteotsunami events, comparable in amplitude and potential impact to moderate seismic tsunamis, occur relatively infrequently\u0026mdash;approximately once every three to five years. Such substantial events are typically generated by fast-moving atmospheric fronts traveling at speeds close to 100 km/h, conditions ideal for triggering Proudman resonance and resulting in pronounced sea-level oscillations.\u003c/p\u003e\u003cp\u003eIn contrast, less intense meteotsunamis occur with higher frequency, averaging about twice per year. Although these events pose a lower risk, their persistence and potential impact on coastal infrastructure and maritime operations make them noteworthy. These moderate events are typically caused by weaker atmospheric fronts, localized thunderstorms, or internal atmospheric gravity waves. The variety of triggering mechanisms highlights the complexity of meteotsunami phenomena and underscores the necessity of maintaining continuous, high-resolution coastal monitoring networks.\u003c/p\u003e\u003cp\u003eThis study integrates empirical observations with numerical modeling to enhance the understanding of meteotsunami generation and amplification in the Southern Kuril Islands. The analysis confirms that rapidly propagating atmospheric pressure anomalies, especially those associated with intense cyclone activity, can induce significant sea-level responses through Proudman resonance when atmospheric disturbance speeds closely match the phase velocities of long oceanic waves over the shelf zone. The significant meteotsunami events in October 2011 and 2018 clearly illustrate this mechanism, exhibiting wave amplitudes comparable to those of moderate seismic tsunamis.\u003c/p\u003e\u003cp\u003eBay geometry, coastline orientation, and entrance characteristics critically influence wave amplification. East-facing and elongated bays such as Malokurilskaya, Krabovaya, and Dimitrova demonstrate pronounced resonance behavior, leading to persistent and substantial sea-level oscillations. Frequency-time diagrams and spectral analyses confirm the dominance of fundamental resonant modes and illustrate spatial variability in the responses among different locations.\u003c/p\u003e\u003cp\u003eMoreover, weaker meteotsunamis not clearly linked to defined atmospheric fronts are associated with alternative atmospheric phenomena such as gravity waves or mesoscale pressure disturbances. These cases highlight the role of high-frequency atmospheric forcing and complex air-sea interactions, warranting further investigation.\u003c/p\u003e\u003cp\u003eNumerical simulations using a modified, nested version of the TUNAMI-N2 model successfully captured the observed spatial and spectral characteristics of meteotsunami events. Despite simplifications in atmospheric forcing inputs and coupling schemes, the model reliably reproduced major resonance peaks, wave amplitudes, and event timing, thereby validating this modeling approach. The simulations further elucidated directional sensitivity and frequency-selective amplification, reinforcing the Proudman resonance mechanism's physical basis in meteotsunami dynamics.\u003c/p\u003e\u003cp\u003eThe identified directional sensitivity and localized amplification mechanisms emphasize the urgent need to integrate detailed bathymetric data and real-time atmospheric monitoring into existing tsunami early-warning systems. Such integration is vital not only for the Southern Kuril Islands but also for similar topographically complex coastal regions globally. Consequently, this study highlights the significance of combining in situ measurements with robust numerical modeling to evaluate and mitigate meteotsunami risks in tectonically and meteorologically active coastal areas. The findings advocate expanding coastal observation networks and refining coupled ocean-atmosphere modeling frameworks, essential for the timely detection and forecasting of meteotsunamis to safeguard maritime operations and support sustainable coastal development.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eCompliance with ethical standards\u003c/h2\u003e\u003cp\u003eConflict of interest The authors declare that they have no competing interests.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eWe greatly appreciate the valuable comments and suggestions provided by Alexander Rabinovich (IORAS, Moscow, Russia) and Isaac Fine (IOS, Sidney, BC, Canada). This work was carried out with the support of the state research project FWWM-2024-0002 of the Institute of Marine Geology and Geophysics FEB RAS.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eBrodtkorb AR, S\u0026aelig;tra ML, Altinakar M (2012) Efficient shallow water simulations on GPUs: Implementation, visualization, verification, and validation. Comput Fluids 55:1\u0026ndash;12. https://doi.org/10.1016/j.compfluid.2011.10.012\u003c/li\u003e\n \u003cli\u003eGiles M, Laszlo E, Reguly I, et al (2014) GPU Implementation of Finite Difference Solvers. In: 2014 Seventh Workshop on High Performance Computational Finance. IEEE, pp 1\u0026ndash;8\u003c/li\u003e\n \u003cli\u003eHeidarzadeh M, \u0026Scaron;epić J, Rabinovich A, et al (2020) Meteorological Tsunami of 19 March 2017 in the Persian Gulf: Observations and Analyses. 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Oceanology (Wash D C) 57:870\u0026ndash;879. https://doi.org/10.1134/S0001437017060145\u003c/li\u003e\n \u003cli\u003eThomson RE (2010) Natural Hazards The meteorological tsunami of 1 November 2010 in the southern Strait of Georgia: A case study\u003c/li\u003e\n \u003cli\u003eVilibić I (2005) Numerical study of the Middle Adriatic coastal waters\u0026rsquo; sensitivity to the various air pressure travelling disturbances. Ann Geophys 23:3569\u0026ndash;3578\u003c/li\u003e\n \u003cli\u003eVilibić I, Monserrat S, Rabinovich A, Mihanović H (2008) Numerical modelling of the destructive meteotsunami of 15 June, 2006 on the coast of the Balearic Islands. Pure Appl Geophys 165:2169\u0026ndash;2195. https://doi.org/10.1007/s00024-008-0426-5\u003c/li\u003e\n \u003cli\u003eVilibić I, Monserrat S, Rabinovich AB (eds) (2015) Meteorological Tsunamis: The U.S. East Coast and Other Coastal Regions. Springer International Publishing, Cham\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"natural-hazards","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nhaz","sideBox":"Learn more about [Natural Hazards](https://www.springer.com/journal/11069)","snPcode":"11069","submissionUrl":"https://submission.nature.com/new-submission/11069/3","title":"Natural Hazards","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Meteotsunamis, Seiches, Atmospheric pressure, Numerical modelling, Spectral analysis, Southern Kuril Islands","lastPublishedDoi":"10.21203/rs.3.rs-7080527/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7080527/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMeteotsunamis are frequent along the coasts of Sakhalin Island and the Kuril Islands, with one or two occurrences typically recorded each year. The most pronounced meteorologically induced long-wave oscillations observed in bays exhibiting strong resonant characteristics\u0026mdash;features that are common throughout the Russian Far East. While meteotsunamis generally pose a moderate hazard, their impact can be significant for ports and vessels, although substantially lower compared to seismic tsunamis. The development of the network of tsunami detectors of the Russian Tsunami Warning Service in main ports of the Kuril Islands, as well as the establishment of autonomous bottom pressure recorders of the Institute of Marine Geology and Geophysics of Far Eastern Branch of Russian Academy of sciences in the coastal area of Southern Kuril Islands (mainly in the bays of Shikotan Island) made it possible to record several meteorologically-induced anomalous sea level oscillation similar to tsunamis during 2009‒2020. We examined in detail the event that occurred in the Southern Kuril Islands on October 16, 2011, recorded by six bottom pressure gauges, and accompanied by digital measurements of surface atmospheric pressure at three sites. Dangerous sea-level oscillations, with a maximum trough-to-crest height of approximately 75 cm in Malokurilskaya Bay, were generated by the passage of an atmospheric front characterized by a pressure drop of approximately 6 mbar and an eastward propagation speed of 100 km/h. A similar generation mechanism was responsible for the most significant meteorological tsunami recorded in the Russian Far East, which occurred on October 1, 2018. The trough-to-crest wave height reached approximately 2 meters along the ocean side of Shikotan Island, an amplitude comparable to that of a moderate seismic tsunami. Numerical simulations of long-wave generation induced by atmospheric disturbances demonstrate that a rapidly propagating atmospheric front along the Lesser Kuril Ridge can produce hazardous sea-level oscillations in the bays of Shikotan Island. This effect arises due to the near-resonant relationship between the front's propagation speed and the phase velocity of long ocean waves approaching the island from both its southeastern and northwestern sides. Two additional events are briefly described. The analysis demonstrates that meteotsunami impacts in the Southern Kuril Islands predominantly arise from Proudman resonance, closely matching the propagation speeds of atmospheric fronts and long ocean waves. Our high-resolution numerical modeling approach elucidates critical resonant mechanisms, directional dependencies, and highlights pronounced bay-specific responses, significantly enhancing regional hazard assessment capabilities.\u003c/p\u003e","manuscriptTitle":"Meteotsunamis in the area of the Southern Kuril Islands: observations and numerical modeling","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-22 15:53:00","doi":"10.21203/rs.3.rs-7080527/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-07-20T21:51:20+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-17T13:12:18+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-09T09:10:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"Natural Hazards","date":"2025-07-09T02:37:17+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"natural-hazards","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nhaz","sideBox":"Learn more about [Natural Hazards](https://www.springer.com/journal/11069)","snPcode":"11069","submissionUrl":"https://submission.nature.com/new-submission/11069/3","title":"Natural Hazards","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9b27f736-04fe-46db-8342-a0bce774273d","owner":[],"postedDate":"July 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-16T16:08:27+00:00","versionOfRecord":{"articleIdentity":"rs-7080527","link":"https://doi.org/10.1007/s11069-026-08060-6","journal":{"identity":"natural-hazards","isVorOnly":false,"title":"Natural Hazards"},"publishedOn":"2026-03-13 15:59:16","publishedOnDateReadable":"March 13th, 2026"},"versionCreatedAt":"2025-07-22 15:53:00","video":"","vorDoi":"10.1007/s11069-026-08060-6","vorDoiUrl":"https://doi.org/10.1007/s11069-026-08060-6","workflowStages":[]},"version":"v1","identity":"rs-7080527","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7080527","identity":"rs-7080527","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}