Shallow crustal velocity structure and tectonic significance beneath Fildes Peninsula, West Antarctica

Shallow crustal velocity structure and tectonic significance beneath Fildes Peninsula, West Antarctica | 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 Shallow crustal velocity structure and tectonic significance beneath Fildes Peninsula, West Antarctica Sun Huigui, Chang Lijun, Lu Laiyu, Qin Tongwei This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5372490/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Apr, 2025 Read the published version in Pure and Applied Geophysics → Version 1 posted 8 You are reading this latest preprint version Abstract Fildes Peninsula is the most exposed area of King George Island, Antarctica, which has experienced frequent volcanic activities, and its strata are composed mainly of basalt and pyroclastic rocks, making it an ideal location for conducting scientific research in Antarctica. This study provides the first constraints on the shallow crustal structure of the peninsula through ambient noise tomography and horizontal-to-vertical spectral ratio (HVSR) analyses by utilizing a denser array of short-period portable seismometers deployed on Fildes Peninsula. The results indicate that the sediment layers on the peninsula are very thin and reveal inhomogeneity within the shallow crust of the study area, which may be related to the characteristics of the surface geological structure. Consistent with crustal activity characteristics observed in most volcanically active regions around the globe, the shallow layers in the study area exhibit predominantly negative radial anisotropy. Our results provide an important imaging basis for the study of shallow crustal structure and deformation on Fildes Peninsula. Fildes Peninsula Ambient noise tomography S-wave velocity Horizontal-to-vertical spectral ratio Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction Fildes Peninsula is located at the southern segment of King George Island, the largest island in the South Shetland Islands, west Antarctica (Fig. 1 ). With an area of approximately 66 km², it features multiple terraces along its coastline and is one of the regions in Antarctica where more bedrock outcropping during the summer (Li et al., 1992 ). Due to the segmented subduction of the Pacific plate to the Antarctic plate, frequent volcanic activities occurred in this area, and volcanic rocks formed the geological structure and surface morphology of Fildes Peninsula through repeated eruptions and cooling (Jordan et al., 2020 ; Zheng et al., 2022 ). Historically, the region's volcanoes have experienced two significant eruptive events with a considerable time interval between them. This allowed the rocks of the peninsula to undergo weathering and erosion. Meanwhile, volcanic clastic materials were deposited and accumulated, and there was a trend of the eruption centers migrating from west to east (Li et al., 1992 ; Zheng et al., 2018 ). According to the field geological investigation, the peninsula is mainly composed of basaltic lava, pyroclastic rocks and thin sedimentary rocks (Liu and Zheng, 1988 ). The isotopic dating results of rocks suggested that volcanism on Fildes Peninsula began in the Late Paleocene and may last until the early Miocene (Zhu et al., 1991). The rock strata of Fildes peninsula are primarily characterized by gentle monoclinic structures, and have not experienced obvious horizontal compression (Zheng et al., 1991 ). The faults in this region can be categorized into two groups based on their orientation: the primary faults are NWW strike-slip normal faults (Fig. 1 ), while some other faults align roughly parallel to the long axis of King George Island and are distributed along the coast. All the faults on the peninsula belong to tensile faults, which indicates that the crust in this area is under horizontal extensional environment, and the fault activities also have formed a small-scale symmetrical fold structure in localized areas. Because of the constraints of the harsh geological environment in Antarctica on the layout of seismic stations, most of the current studies on Fildes Peninsula focus on geology, geomorphology, petrology, isotope geochronology, geochemistry, geomorphology and so on, with relatively few seismic imaging methods being applied and explored for underground structural and deformation features. For the entire Antarctic region, previous studies have employed methods such as receiver functions (Parera-Portell et al., 2021 ; Ramirez et al., 2016), surface wave tomography (Li et al., 2021 ; Muhumuza, 2020 ; Shen et al., 2018 ; Zhou et al., 2022 ), and gravity and magnetic (Almendros et al., 2020 ) to investigate the deformation characteristics of the subsurface media in Antarctica. However, these studies are mostly confined to the study of the Antarctic continental ice sheet as well as deep crustal structures, with insufficient reflection of high-frequency information regarding shallow crustal structures. The ambient noise tomography method obtains the approximate empirical Green's function between two stations by cross-correlating the noise data recorded simultaneously at both stations, thereby extracting the surface wave signals (Shapiro et al., 2004 ). Due to the method's independence from seismic events, it has been widely used to study the velocity structure of crust and upper mantle since it was proposed (Yao et al., 2011 ; Yang et al., 2012 ; Liang et al., 2022 ). In recent years, the development of dense arrays of short-period seismometers has enabled the recovery of high-frequency dispersion signals with a relatively dense average station spacing, significantly enhancing the resolution of shallow noise tomography (Qin et al., 2022 ). In addition, it has been found that seismic ambient noise data can effectively reveal the relationship between resonance frequency and site amplification factor (Nakamura, 1989 , 2019 ). The peak of horizontal-to-vertical (H/V) spectral ratio curve is caused by the resonance of S-waves within sedimentary layers, and the resonance frequency of the shallow sedimentary layers is basically close to the peak frequency. Currently, analyzing the three-dimensional undulating characteristics of sedimentary layers and the site response of shallow crustal deposits using the H/V spectral ratio method has become a new research direction. In this study, we used a dense array of short-period seismometers deployed on Fildes Peninsula in Antarctica to extract high-frequency (0.2-2.0 s) Rayleigh wave and Love wave dispersion curves using the ambient noise tomography method. We then inverted the three-dimensional SV wave and SH wave velocity structures using a two-step approach and discussed the shallow crustal structure of the study area in conjunction with the HVSR method. 2. Data and methods 2.1. Data This study utilized a station array (Fig. 1 b) composed of three-component short-period portable seismometers deployed on Fildes Peninsula, west Antarctica, by the Institute of Geophysics, China Earthquake Administration. The sampling rate of the instruments is 250 Hz, and the observation period lasts from December 31, 2023, to January 21, 2024. The longest observation time for a single station is 21 days, while the shortest is 7 days. The maximum elevation of the stations is 96 m, the minimum is 10 m, and the average distance between stations is approximately 600 m. 2.2. Ambient noise analysis and tomography Based on the continuous noise data recorded by stations, the empirical Green's function of surface wave can be obtained by calculating the cross-correlation function, and then the dispersion data can be extracted. Following the data processing procedures outlined by Bensen et al. ( 2007 ), we first resampled the original waveform data to 100 Hz to improve the computational speed of the program. Subsequently, preprocessing steps such as removal of means and trends, band-pass filtering (0.1-5 s), time-domain and frequency-domain normalization were performed. Cross-correlation calculations were conducted for station pairs within the same time windows and stacked all the results, we ultimately obtained a total of 156 cross-correlation functions. Figure 2 shows the cross-correlation function of the vertical and tangential components within the frequency band of 0.3-5.0 Hz, clearly showing the velocity signals of Rayleigh and Love waves. Therefore, we choose to extract the dispersions of cross-correlation functions in this period range. The surface wave dispersion curve is extracted by image transformation technique (Yao et al., 2006 ). For the quality control of dispersion curves, we abandon the dispersion data with signal-to-noise ratio lower than 5, and set the control condition that the distance between stations is greater than 1.2 times the wavelength, because when the distance between stations exceeds one time wavelength, it can effectively reduce the propagation time difference between the exact Green's function and the far-field asymptotic Green's function (Yao et al., 2011 ). Finally, we selected 136 Rayleigh wave group velocity dispersion curves, 125 Rayleigh wave phase velocity dispersion curves, and 125 Love wave group velocity dispersion curves within the period range of 0.2 to 2.0 s, as shown in Fig. 3 . It should be noted that the quality of the Love wave phase velocity dispersion curves in this study is relatively poor, so the inversion of Love wave phase velocity will be no longer considered. In this paper, we employ the Fast Marching Surface Wave Tomography method (Rawlinson and Sambridge, 2004 ) for the inversion of two-dimensional phase and group velocities. Generally, the propagation paths of short-period surface waves deviate from great circle paths, and this method takes into account the bending effect of surface wave ray paths, making it more suitable for shallow crustal studies. The checkerboard test can evaluate the ability of the tomography method to resolve velocity anomalies at different scales. We chose a grid division of 0.02° × 0.01°, with velocity perturbations set at ± 3%. Despite the relatively small number of stations in this study, the recovery results indicate that the anomalous body can still be recovered in most areas (Fig. 4 ). Therefore, we choose to invert for the pure-path dispersions and two-dimensional velocity maps of Rayleigh and Love waves with different periods under this grid (Fig. 5 ). According to the pure path dispersions obtained at different grid points, we employed linear iterative inversion program (surf96) to obtain the one-dimensional S-wave velocity structure below each grid point. Furthermore, we need to construct an initial model for the inversion process, as an initial model that is closer to the real model can ensure the reliability of the inversion results. This study refers to the conversion formula of surface wave velocity and wavelength proposed by previous studies (Liu et al., 2018 ; Suemoto et al., 2020 ), which involve multiplying the phase velocity measured at a depth of one-third of the wavelength by 1.1, and using the approximate converted average shear wave velocity as the initial model (Figs. 6 a-b). In addition, the values of P wave velocity and density required by the initial model are calculated by the Nafe-Drake empirical formula (Brocher, 2005 ). During the inversion process, the thickness of each layer is set to 0.1 km. Based on the depth sensitivity kernel for the velocity dispersion of Rayleigh and Love waves at different periods that we have calculated (Fig. 7 ), it is appropriate to set the inversion depth above 2 km. Therefore, by combining the group velocity and phase velocity dispersions of Rayleigh waves, we inverted the one-dimensional SV wave velocity structure beneath each grid point. By independently inverting the pure-path dispersions of Love wave group velocity, we obtained the one-dimensional SH wave velocity structure. Finally, we combined the velocity structures of all grid points within the study area and used linear interpolation to obtain the 3-D SV and SH wave velocity structures (Fig. 10 ). 2.3. H/V spectral ratio The Horizontal-to-Vertical Spectral Ratio is a passive seismological method for evaluating site seismic response. It estimates the resonance frequency (HVSR peak frequency or period) and site amplification factor by measuring the spectral ratio of horizontal to vertical components of ambient noise signals. The basic calculation formula for the HVSR method is as follows: $$\:HVSR\left(f\right)=\frac{\sqrt{{\left|{H}_{x}\left(f\right)\right|}^{2}+{\left|{H}_{y}\left(f\right)\right|}^{2}}}{\left|V\left(f\right)\right|}$$ 1 where \(\:{H}_{x}\left(f\right)\) and \(\:{H}_{y}\left(f\right)\) are the Fourier amplitudes of the horizontal components \(\:x\) and \(\:y\) at frequency \(\:f\) , respectively, and \(\:V\left(f\right)\) is the Fourier amplitude of the vertical components at frequency \(\:f\) . In practical applications, the recorded ambient noise signals are typically preprocessed. We segment the three-component continuous waveform data into 400-second time windows with a moving step of 200 seconds. By applying filtering and smoothing techniques, a clear HVSR curve is extracted (Fig. 8 ). The peak frequency of the HVSR curve is generally regarded as the resonance frequency of the site, while the peak amplitude is related to the site amplification factor. Thus, the thickness \(\:h\) of bedrock can be inferred from the fundamental resonance frequency \(\:{\:f}_{0}\) of the HVSR curve (Seht and Wohlenberg, 1999 ; Parolai et al., 2002 ). The relationship is given as follows: $$\:h=\frac{{V}_{s}}{4{f}_{0}}$$ 2 where \(\:{V}_{s}\) is the average S-wave velocity of the sedimentary layer. Since the study area is located on sparsely populated Antarctic islands, there are no related imaging results yet that can distinguish the S wave velocity structure at the shallow surface. Therefore, here we adopt the empirical relational formula proposed by previous researchers (Seht and Wohlenberg, 1999 ), which is as follows: $$\:h=a{f}_{0}^{b}$$ 3 Where \(\:a\) and \(\:b\) are constants determined through data fitting of soil-rock interface depth calibrated by borehole and picked peak frequency. Due to the lack of borehole data in this area, we choose h = 96 \(\:{f}_{0}^{-1.388}\) (Parolai et al., 2002 ) to estimate the bedrock thickness of Fildes Peninsula. 3. Results 3.1. Group velocity structure Figure 5 shows the horizontal distribution of the group velocities of Rayleigh and Love waves with periods of 0.5, 1.0 and 1.5 s. At a shorter period of 0.5 s (Figs. 5 a and d), the results of Rayleigh wave and Love wave group velocities are relatively consistent. The low-velocity bodies are mainly distributed in Agate Beach and the northeast of Ardley Cove, while Fossil Hill area mainly exhibits high-velocity anomalies. At the period of 1.0 s, the group velocities of Rayleigh wave near Agate Beach show obvious low-velocity anomalies (Fig. 5 b), while the low-velocity zones of Love wave are mainly distributed in the western side of Jasper Mountain and the northern part of Ardley Cove, the high-velocity anomalies are shown in the area from Fossil Hill to Block Hill (Fig. 5 e). At the period of 1.5 s, the group velocities of Rayleigh wave (Fig. 5 c) reveal that the area from Block Hill to Ardley Cove exhibiting obvious high-velocity anomalies, and the western part of the peninsula with faults shows low-velocity characteristics. The group velocities of Love wave are consistent with that of the Rayleigh wave, but there are still some low-velocity anomalies in the northern Ardley Cove (Fig. 5 f). 3.2. Near-surface structures assessment from HVSR By normalizing the amplitude of stations, the HVSR resonance frequency distribution and calculated thickness distribution at the shallow surface of Fildes Peninsula are shown in Fig. 9 . We can see that the peak of resonance frequency for each station is basically above 10 Hz, and the average depth of sedimentary layers is within 5 m according to the formula transformation. For the stations near Fossil Hill and Block Hill (e.g., CC20, CC19, CC17), which are all at elevation depths of 90 m or more, the stratigraphy beneath them may not contain sedimentary layers. The thickness of the sedimentary layer beneath some of the stations along the coast (CC04, CC12, CC02) is relatively more pronounced. 4. Discussion Using ambient noise tomography and the HVSR methods can provide useful information for exploring the sedimentary environment of Fildes Peninsula. As an island primarily composed of volcanic rocks, the Fildes Peninsula underwent two magmatic differentiation processes during its formation, with its surface predominantly covered by high-alumina basalts and basaltic andesites (Li et al., 1992 ; Zheng et al., 2018 ; Wang et al., 2013 ). The rock composition of volcanic islands is typically closely related to volcanic activity, thus their formation background differs from that of continental crust, and the rock composition primarily originates from magma, volcanic ash, and volcanic debris produced by volcanic eruptions. According to the HVSR of 23 stations, the peak frequencies are mainly distributed between 10 Hz and 50 Hz (Fig. 9 a), whereas the site resonance frequencies in continental areas are usually lower than 10 Hz (Ma et al., 2024 ; Qin et al., 2022 ; Wang et al., 2020 ). The shallow development of the sedimentary layer below the station can also be seen by the calculation of the frequency-depth conversion formula (Fig. 9 b). Based on the spatial distribution of stations, the sedimentary layers along the coast of the peninsula are relatively thicker compared to those in the central region. For example, the resonance frequencies beneath both the station CC04 located on the riverbank and the station CC12 positioned at the edge of the ice sheet are relatively low, which we believe may be related to the formation of certain accumulation layers at the lower elevation coastal area under the influence of various dynamics such as rivers, waves, tides. In addition, the analysis of samples collected in the southeast corner of the peninsula by previous researchers (Shen, 1992 ) revealed that this area is mainly composed of volcanic breccia, tuff, tuffaceous sandstone and tuffaceous mudstone, possibly representing lacustrine deposits near the coast with a thickness of approximately 5.5 meters, which further corroborates our findings. Due to the constraints of geographical location and climatic conditions, there are relatively few tomography studies on Antarctica at present. Current imaging results in this area mainly focus on construction of large-scale three-dimensional velocity models to explore the crust-mantle deformation characteristics such as Bransfield Basin and South Shetland Trench (Li et al., 2021 ; Muhumuza, 2020 ). The three-dimensional shear wave velocity model of the shallow crust of Fildes Peninsula obtained in this paper can provide a new imaging basis for the study of regional tectonic and deformation (Fig. 10 ), and reveal the anisotropic characteristics of the shallow crust. At a depth of 0.6 km, there is a consistency between the velocity structure and the fault distribution. The SV and SH waves in the fault distribution area on the southwest side of the peninsula mostly show low-velocity anomalies, with this feature being more prominent in the SH wave velocity structure. Additionally, low-velocity anomalies are also distributed in the northern part of Ardley Cove. At a depth of 1.2 km, the area from Fossil Hill to Block Hill mainly exhibits high-velocity anomalies, indicating its relatively stable crustal structure. At a greater depth of 1.8 km, there are certain differences in SV and SH wave velocities. Specifically, the SH waves in the Agate Beach and the eastern part of Jasper Hill mainly show low-velocity structures, while the low-velocity areas for SV waves are primarily distributed around Jasper Hill. The high-velocity anomalies are mainly distributed in the area from Ardley Cove to Block Hill. It can be observed from the distribution of peninsula faults that there are several NW and NWW faults distributed in Agate Beach and Jasper Hill, and rock fragmentation, fracture development and possible fluid filling in the fault zone will increase the propagation path of waves, which will make the propagation velocity of S waves decay faster (Liang et al., 2023 ; Ma et al., 2020 ). In addition, lithological characteristics and isotopic geochemical studies of the exposed igneous rocks (Li et al., 1992 ) indicate a trend of gradually younger volcanic rock ages from southwest to northeast on Fields Peninsula. The first stage is dated to the Paleocene, with volcanic eruption centers concentrated in the Jasper Hill and Agate Beach sections. The second stage is dated to the Eocene, with volcanic eruption centers distributed more dispersedly in the Fossil Hill and Block Hill. Our velocity structure corresponds well with the volcanic rock ages. Due to earlier volcanic activity in the southwest, subsequent magma intruded along the NW and NWW regional fractures on the western side of the peninsula. After undergoing prolonged weathering and erosion, the density and rigidity of the shallow igneous rocks were weakened, resulting in lower velocity structures. In the area from Fossil Hill to Block Hill, the shear wave velocity structures show high-velocity anomalies due to relatively young metamorphic rocks on the surface and shallow underground. The vertical profile slices allow the study of the depth-influenced range of 3-D velocity structures. As shown in Fig. 11 , there is a positive correlation between the velocities and depth of both SV waves and SH waves. It is noteworthy that there exists a low-velocity layer with a depth of approximately 1 km in the northern part of Ardley Cove. The factors influencing shallow velocity anomalies are not only related to material composition, porosity, and water content, but also to fault structures (Nimiya et al., 2020 ). It can be seen from the geological map of Fildes Peninsula (Fig. 1 c), there are mainly breccia of Fossil Hill Member, tuff and pyroclastic rocks in this area. Furthermore, the sedimentary environment in this region differs from the lacustrine sediments on the southeast side of the peninsula, belonging to small-scale intermontane basin accumulation (Shen, 1992 ). This area also corresponds to the southeast segment of the largest fault on the peninsula, which may have further cut through the shallow crust. Therefore, volcaniclastic sedimentary rocks, along with the overlying layers and NWW trending faults, may be the causes of low-velocity anomalies. By comparing the velocities of SV waves and SH waves, we find that the shallow crust of Fildes Peninsula mainly exhibits negative radial anisotropy, which aligns with the characteristics of the shallow subsurface in volcanic regions (Lee et al., 2021 ; Mordret et al., 2014). Negative radial anisotropy may arise from the alteration of the oriented arrangement of fluid-bearing microfractures and pores due to crustal stress induced by the upward movement of magma prior to volcanic eruptions, further affecting the propagation characteristics of seismic waves. In summary, we believe that the shallow crustal medium structure of Fildes Peninsula exhibits significant inhomogeneity, and the distribution of velocity anomalies has a strong correlation with surface geological structures. Due to the relatively limited number of seismic stations, this study discusses the shallow medium structure and dynamic mechanisms of Fildes Peninsula within the maximum range of station distribution, the resolution in the marginal areas may not be ideal. In the future, it is expected that more seismic stations will be deployed to conduct higher-resolution and more in-depth research on the island. 5. Conclusions In this study, we utilized continuous waveform data recorded by short-period dense array on Fildes Peninsula to conduct ambient noise tomography and HVSR analysis, obtaining the characteristics of the shallow crust structure in this region. Our results indicate that the near-surface sedimentary layers on the peninsula are very shallow, with thicker layers near the coast compared to the center of the island. Additionally, the three-dimensional S-wave velocity structure exhibits a strong correlation with the surface geological structures and reveals the inhomogeneity of the shallow crustal medium in this area. The metamorphic rocks formed during earlier volcanic activity have lower velocities than those formed during later periods, and fault structures also locally influence shallow crustal velocity anomalies. By comparing the velocity structures of SV waves and SH waves, the shallow layer of the study area mainly exhibits negative radial anisotropy, which accords with the characteristics of shallow subsurface activity in volcanic regions. Declarations Author Contribution S.H. wrote the main manuscript text. All authors reviewed the manuscript. Acknowledgments We acknowledge the efforts of staff involved in the Chinese 40th Antarctic Scientific Expedition Team in collecting the data used in this study. 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Chinese Journal of Polar Research 4 (2), 18–26 (in Chinese with English abstract). https://journal.chinare.org.cn/CN/Y1992/V4/I2/18 . Suemoto, Y., Ikeda, T., Tsuji, T., Iio, Y., 2020. Identification of a nascent tectonic boundary in the San-in area, southwest Japan, using a 3D S-wave velocity structure obtained by ambient noise surface wave tomography. Earth Planets Space 72, 15. https://doi.org/10.1186/s40623-020-1139-y . Wang, G., Deng, X., Liu, J., Du, M., 2013. Stratigraphic characteristics of the Mesozoic-Cenozoic in the south Shetland Islands, Antarctica. Advances In Polar Science 25 (2), 161–166 (in Chinese with English abstract). https://journal.chinare.org.cn/CN/Y2013/V25/I2/161 . Wang, S., Sun, X., Liu, L., Zong, J., 2020. Sub-surface structures and site effects extracted from ambient noise in metropolitan Guangzhou, China. Engineering Geology 268, 105526. https://doi.org/10.1016/j.enggeo.2020.105526 . Yang, Y., Ritzwoller, M.H., Zheng, Y., Shen, W., Levshin, A.L., Xie, Z., 2012. A synoptic view of the distribution and connectivity of the mid-crustal low velocity zone beneath Tibet: MID-CRUSTAL LOW VELOCITY ZONE IN TIBET. J. Geophys. Res. 117, n/a-n/a. https://doi.org/10.1029/2011JB008810 . Yao, H., Gouédard, P., Collins, J.A., McGuire, J.J., Van Der Hilst, R.D., 2011. Structure of young East Pacific Rise lithosphere from ambient noise correlation analysis of fundamental- and higher-mode Scholte-Rayleigh waves. Comptes Rendus. Géoscience 343, 571–583. https://doi.org/10.1016/j.crte.2011.04.004 . Yao, H., van der Hilst, R., de Hoop, M., 2006. Surface-wave array tomography in SE Tibet from ambient seismic noise and two-station analysis—I. Phase velocity maps. Geophysical Journal International 166 (2), 732–744. https://doi.org/10.1111/j.1365-246X.2006.03028.x . Zheng, G., Liu, X., Liu, S., Zhang, S., Zhao, Y., 2018. Late Mesozoic-early Cenozoic intermediate-acid intrusive rocks from the Gerlache Strait area, Antarctic Peninsula: Zircon U-Pb geochronology, petrogenesis and tectonic implications. Lithos 312–313, 204–222. https://doi.org/10.1016/j.lithos.2018.05.008 . Zheng, G., Liu, X., Pei, J., Zhao Y., Chen, H., Lj, J., 2022. Early Palaeogene mafic–intermediate dykes, Robert Island, West Antarctica: Petrogenesis, zircon U–Pb geochronology, and tectonic significance. Geological Journal 57(6), 2209–2220. https://doi.org/10.1002/gj.4402 . Zheng, X., E, M., Liu, X., Zhu, M., Li, J., 1991. The volcanic geology, Petrological characteristics and the formation and evolution of the tertiary volcanic rocks from the great wall station area, King George Island, West Antarctica. Chinese Journal of Polar Research 3 (2), 10–108 (in Chinese with English abstract). https://journal.chinare.org.cn/CN/Y 1991/V3/I2/10. Zhou, Z., Wiens, D.A., Shen, W., Aster, R.C., Nyblade, A., Wilson, T.J., 2022. Radial Anisotropy and Sediment Thickness of West and Central Antarctica Estimated From Rayleigh and Love Wave Velocities. JGR Solid Earth 127, e2021JB022857. https://doi.org/10.1029/2021JB022857 . Zhu, M., E, M., Zheng, X., 1991. The isotope age of the vocanic rocks and the correlation of stratigraphy in the Fildes Peninsula, King George Island, West Antarctica. Chinese Journal of Polar Research 3 (2), 126–135 (in Chinese with English abstract). https://journal.chinare.org.cn/CN/Y1991/V3/I2/126 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 09 Apr, 2025 Read the published version in Pure and Applied Geophysics → Version 1 posted Editorial decision: Revision requested 10 Feb, 2025 Reviews received at journal 13 Jan, 2025 Reviewers agreed at journal 28 Dec, 2024 Reviewers agreed at journal 10 Dec, 2024 Reviewers invited by journal 08 Dec, 2024 Editor assigned by journal 02 Nov, 2024 Submission checks completed at journal 02 Nov, 2024 First submitted to journal 01 Nov, 2024 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-5372490","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":375932772,"identity":"37e78e92-72e6-406e-8775-96df83b86bd3","order_by":0,"name":"Sun Huigui","email":"","orcid":"","institution":"China Earthquake Administration","correspondingAuthor":false,"prefix":"","firstName":"Sun","middleName":"","lastName":"Huigui","suffix":""},{"id":375932773,"identity":"23abde2c-0840-49b1-9a9e-30a40e353e91","order_by":1,"name":"Chang Lijun","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYBACPoYDbCBaDsxLIEYLG1SLMSlaGMBaEhuIdhgb4+FnD37uqE3vb29+wPDg1x0G/vYDjJ8L8NpyzNyw98zx3BlnjhkwJPY9Y5A4k8AsPQOvljNsErxtx3I3SCSY/0jsOczAcIOBjZmHgBbJv23H0g3kn39gAGmRJ0aLNG9bTYKBBI8BQ8KPwwwGhLUcM5OWbTtgOONMTgEw3J7xGJ5JbJbGp4Vf4vAzybdtdfL87cc3MP74c0dO7vjhg5/xaWGQOAAiD0M4jG0HgIoZG/BpAFoDlq+D8v4cwK96FIyCUTAKRiQAAICGTEPL/wCoAAAAAElFTkSuQmCC","orcid":"","institution":"China Earthquake Administration","correspondingAuthor":true,"prefix":"","firstName":"Chang","middleName":"","lastName":"Lijun","suffix":""},{"id":375932774,"identity":"16874d82-7d34-49c9-b35e-53a31ccdec2d","order_by":2,"name":"Lu Laiyu","email":"","orcid":"","institution":"China Earthquake Administration","correspondingAuthor":false,"prefix":"","firstName":"Lu","middleName":"","lastName":"Laiyu","suffix":""},{"id":375932775,"identity":"79c5f7fd-5f0e-4c69-9f8e-9f92e3d8d5c5","order_by":3,"name":"Qin Tongwei","email":"","orcid":"","institution":"China Earthquake Administration","correspondingAuthor":false,"prefix":"","firstName":"Qin","middleName":"","lastName":"Tongwei","suffix":""}],"badges":[],"createdAt":"2024-11-01 10:08:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5372490/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5372490/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00024-025-03712-3","type":"published","date":"2025-04-09T16:05:22+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":70286316,"identity":"0d53fbc2-ec9c-4074-baac-b73ec04d3bdd","added_by":"auto","created_at":"2024-12-01 16:32:29","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":3224285,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Main tectonic units of South Shetland Islands in west Antarctica. (b) Distribution of seismic stations on Fildes Peninsula. The orange triangles are the stations deployed during 2023.12.30-2024. 01.13; The green triangles are the stations deployed during the period from 2024.01.11-2024.01.22. The red triangle is the station deployed during 2023.12.30-2024.01.22. Black solid lines represent faults; The solid red line represents the profile line in Fig. 11. (c) Geological map of Fildes Peninsula (modified from Li et al., 1992). 1. Quaternary; 2. Basalt of Long Hill Member; 3. Block Hill Member; 4. Lava and breccia of Block Hill Member; 5. Agglomerate of Block Hill Member; 6. Volcanic sedimentary Fossil Hill Member; 7. Agate Beach Member; 8. Basalt and Basaltic andesite of Agate Beach Member; 9. Volcanic Breccia and Agglomerate of Agate Beach Member; 10. Basalt of Jasper Hill Member; 11. Agglomerate of Jasper Hill Member; 12. Subvolcanic rocks; 13. Dyke; 14. Fault.\u003c/p\u003e","description":"","filename":"fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/d4293a78c9ceaa450c79154e.jpg"},{"id":70286306,"identity":"2eaae5a6-a068-4c6e-87e5-eed53364128d","added_by":"auto","created_at":"2024-12-01 16:32:29","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1005589,"visible":true,"origin":"","legend":"\u003cp\u003eCross-correlation function waveforms of vertical component (a) and tangential component (b) for all station pairs within the 0.3-5.0 Hz band range.\u003c/p\u003e","description":"","filename":"fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/f59341ad44aa264fcbc09997.jpg"},{"id":70287038,"identity":"cba7b8bc-c4a6-43ef-8b0b-d78bd3f6db6c","added_by":"auto","created_at":"2024-12-01 16:48:29","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":276314,"visible":true,"origin":"","legend":"\u003cp\u003eThe fundamental mode (a) Rayleigh wave group velocity dispersion curves (pink solid line) and phase velocity dispersion curves (blue solid line), (b) Love wave group velocity dispersion curves (pink solid line), and the number of dispersion curves for each period within the range of 0.2 to 2.0 s.\u003c/p\u003e","description":"","filename":"fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/2b902942941434d53ffca162.jpg"},{"id":70286896,"identity":"e9835b76-fafb-4dd2-95de-505e662a6c58","added_by":"auto","created_at":"2024-12-01 16:40:29","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2757771,"visible":true,"origin":"","legend":"\u003cp\u003eCheckboard resolution tests. (a) Input model for 0.02° × 0.01° anomaly sizes. Recovery model of Rayleigh wave group velocity (RGV, b-d) and Love wave group velocity (LGV, e-g) for periods of 0.5 s, 1.0 s and 1.6 s. The gray solid lines represent the ray paths for each period and the number (N) of which is labelled on the upper left.\u003c/p\u003e","description":"","filename":"fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/baad67f55bb1c418eca5c350.jpg"},{"id":70286315,"identity":"3039804d-457f-472c-a008-7eb00594f124","added_by":"auto","created_at":"2024-12-01 16:32:29","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1799841,"visible":true,"origin":"","legend":"\u003cp\u003e(a)-(f) Group velocity maps of Rayleigh and Love waves at periods of 0.5, 1.0, and 1.5 s, respectively.\u003c/p\u003e","description":"","filename":"fig5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/7ff03783de4efbd4f6c09a25.jpg"},{"id":70286895,"identity":"23624ece-1d46-4393-91bb-4a736ad17184","added_by":"auto","created_at":"2024-12-01 16:40:29","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":425937,"visible":true,"origin":"","legend":"\u003cp\u003eExample of SV and SH wave velocity-depth inversion on Fildes Peninsula. (a-b) Initial model of one-dimensional average velocity of SV wave and SH wave in inversion process. (c) Observed pure-path dispersions of Rayleigh-wave group velocity and phase velocity and synthetic dispersion curves. (d) Pure-path dispersions of Love-wave group velocity and synthetic dispersion curve; (d) Inverted velocity models of SV and SH waves.\u003c/p\u003e","description":"","filename":"fig6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/e188c3f87ba722339d30295a.jpg"},{"id":70286899,"identity":"c315d554-6ce8-474a-8eec-3fc4487e9ff7","added_by":"auto","created_at":"2024-12-01 16:40:29","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":596099,"visible":true,"origin":"","legend":"\u003cp\u003eDepth sensitive kernels of (a) Rayleigh wave group velocity, (b) Rayleigh wave phase velocity and (c) Love wave group velocity to S wave velocity for period 0.5, 1.0, 1.5, 2.0 s (U, C and Vs represent group velocity, phase velocity and S wave velocity, respectively).\u003c/p\u003e","description":"","filename":"fig7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/ca90141d1cf2f0da9ac7e031.jpg"},{"id":70286310,"identity":"fa26ae8b-32fb-4ec3-898d-3647005b50ea","added_by":"auto","created_at":"2024-12-01 16:32:29","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":157169,"visible":true,"origin":"","legend":"\u003cp\u003eHVSR curves for three different stations.\u003c/p\u003e","description":"","filename":"fig8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/64ccd3fd4d143dca4e666be3.jpg"},{"id":70286897,"identity":"8e7f18e6-6f08-4093-9922-a552aaaeb151","added_by":"auto","created_at":"2024-12-01 16:40:29","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":975176,"visible":true,"origin":"","legend":"\u003cp\u003eThe normalized H/V profiles plotted as the frequency (a) and the transferred depth (b) for all stations. (c) Thickness of the sedimentary layer estimated below the station.\u003c/p\u003e","description":"","filename":"fig9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/876c5c36a5b5a99f8a7bdfed.jpg"},{"id":70286317,"identity":"4b564179-a980-4ec9-baa8-97ad15b4a599","added_by":"auto","created_at":"2024-12-01 16:32:29","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":2455565,"visible":true,"origin":"","legend":"\u003cp\u003eHorizontal profiles of 3-D SV (left) and SH (right) wave velocity models at 0.6, 1.2 and 1.8 km.\u003c/p\u003e","description":"","filename":"fig10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/54d7ce0c41a02bea1500926a.jpg"},{"id":70286309,"identity":"74a6a9c5-4e16-4901-a078-cd4fa31f6ce4","added_by":"auto","created_at":"2024-12-01 16:32:29","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":550836,"visible":true,"origin":"","legend":"\u003cp\u003eThe vertical slice maps of SV (left) and SH (right) wave velocity for the profile shown in Fig. 1b.\u003c/p\u003e","description":"","filename":"fig11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/661d77f088d288b4032ab348.jpg"},{"id":80558601,"identity":"66bfade7-dbb9-4f22-8d25-59e8adcf8d36","added_by":"auto","created_at":"2025-04-14 16:14:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":14711088,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5372490/v1/6c41b570-5f2e-46e7-a10a-c0e1f8a035f6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Shallow crustal velocity structure and tectonic significance beneath Fildes Peninsula, West Antarctica","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eFildes Peninsula is located at the southern segment of King George Island, the largest island in the South Shetland Islands, west Antarctica (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). With an area of approximately 66 km\u0026sup2;, it features multiple terraces along its coastline and is one of the regions in Antarctica where more bedrock outcropping during the summer (Li et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1992\u003c/span\u003e). Due to the segmented subduction of the Pacific plate to the Antarctic plate, frequent volcanic activities occurred in this area, and volcanic rocks formed the geological structure and surface morphology of Fildes Peninsula through repeated eruptions and cooling (Jordan et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Zheng et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Historically, the region's volcanoes have experienced two significant eruptive events with a considerable time interval between them. This allowed the rocks of the peninsula to undergo weathering and erosion. Meanwhile, volcanic clastic materials were deposited and accumulated, and there was a trend of the eruption centers migrating from west to east (Li et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Zheng et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). According to the field geological investigation, the peninsula is mainly composed of basaltic lava, pyroclastic rocks and thin sedimentary rocks (Liu and Zheng, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1988\u003c/span\u003e). The isotopic dating results of rocks suggested that volcanism on Fildes Peninsula began in the Late Paleocene and may last until the early Miocene (Zhu et al., 1991).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe rock strata of Fildes peninsula are primarily characterized by gentle monoclinic structures, and have not experienced obvious horizontal compression (Zheng et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e1991\u003c/span\u003e). The faults in this region can be categorized into two groups based on their orientation: the primary faults are NWW strike-slip normal faults (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), while some other faults align roughly parallel to the long axis of King George Island and are distributed along the coast. All the faults on the peninsula belong to tensile faults, which indicates that the crust in this area is under horizontal extensional environment, and the fault activities also have formed a small-scale symmetrical fold structure in localized areas. Because of the constraints of the harsh geological environment in Antarctica on the layout of seismic stations, most of the current studies on Fildes Peninsula focus on geology, geomorphology, petrology, isotope geochronology, geochemistry, geomorphology and so on, with relatively few seismic imaging methods being applied and explored for underground structural and deformation features. For the entire Antarctic region, previous studies have employed methods such as receiver functions (Parera-Portell et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Ramirez et al., 2016), surface wave tomography (Li et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Muhumuza, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Shen et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Zhou et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), and gravity and magnetic (Almendros et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) to investigate the deformation characteristics of the subsurface media in Antarctica. However, these studies are mostly confined to the study of the Antarctic continental ice sheet as well as deep crustal structures, with insufficient reflection of high-frequency information regarding shallow crustal structures.\u003c/p\u003e \u003cp\u003eThe ambient noise tomography method obtains the approximate empirical Green's function between two stations by cross-correlating the noise data recorded simultaneously at both stations, thereby extracting the surface wave signals (Shapiro et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Due to the method's independence from seismic events, it has been widely used to study the velocity structure of crust and upper mantle since it was proposed (Yao et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Yang et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Liang et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In recent years, the development of dense arrays of short-period seismometers has enabled the recovery of high-frequency dispersion signals with a relatively dense average station spacing, significantly enhancing the resolution of shallow noise tomography (Qin et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In addition, it has been found that seismic ambient noise data can effectively reveal the relationship between resonance frequency and site amplification factor (Nakamura, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e1989\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The peak of horizontal-to-vertical (H/V) spectral ratio curve is caused by the resonance of S-waves within sedimentary layers, and the resonance frequency of the shallow sedimentary layers is basically close to the peak frequency. Currently, analyzing the three-dimensional undulating characteristics of sedimentary layers and the site response of shallow crustal deposits using the H/V spectral ratio method has become a new research direction. In this study, we used a dense array of short-period seismometers deployed on Fildes Peninsula in Antarctica to extract high-frequency (0.2-2.0 s) Rayleigh wave and Love wave dispersion curves using the ambient noise tomography method. We then inverted the three-dimensional SV wave and SH wave velocity structures using a two-step approach and discussed the shallow crustal structure of the study area in conjunction with the HVSR method.\u003c/p\u003e"},{"header":"2. Data and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Data\u003c/h2\u003e \u003cp\u003eThis study utilized a station array (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb) composed of three-component short-period portable seismometers deployed on Fildes Peninsula, west Antarctica, by the Institute of Geophysics, China Earthquake Administration. The sampling rate of the instruments is 250 Hz, and the observation period lasts from December 31, 2023, to January 21, 2024. The longest observation time for a single station is 21 days, while the shortest is 7 days. The maximum elevation of the stations is 96 m, the minimum is 10 m, and the average distance between stations is approximately 600 m.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Ambient noise analysis and tomography\u003c/h2\u003e \u003cp\u003eBased on the continuous noise data recorded by stations, the empirical Green's function of surface wave can be obtained by calculating the cross-correlation function, and then the dispersion data can be extracted. Following the data processing procedures outlined by Bensen et al. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), we first resampled the original waveform data to 100 Hz to improve the computational speed of the program. Subsequently, preprocessing steps such as removal of means and trends, band-pass filtering (0.1-5 s), time-domain and frequency-domain normalization were performed. Cross-correlation calculations were conducted for station pairs within the same time windows and stacked all the results, we ultimately obtained a total of 156 cross-correlation functions. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the cross-correlation function of the vertical and tangential components within the frequency band of 0.3-5.0 Hz, clearly showing the velocity signals of Rayleigh and Love waves. Therefore, we choose to extract the dispersions of cross-correlation functions in this period range.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe surface wave dispersion curve is extracted by image transformation technique (Yao et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). For the quality control of dispersion curves, we abandon the dispersion data with signal-to-noise ratio lower than 5, and set the control condition that the distance between stations is greater than 1.2 times the wavelength, because when the distance between stations exceeds one time wavelength, it can effectively reduce the propagation time difference between the exact Green's function and the far-field asymptotic Green's function (Yao et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Finally, we selected 136 Rayleigh wave group velocity dispersion curves, 125 Rayleigh wave phase velocity dispersion curves, and 125 Love wave group velocity dispersion curves within the period range of 0.2 to 2.0 s, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. It should be noted that the quality of the Love wave phase velocity dispersion curves in this study is relatively poor, so the inversion of Love wave phase velocity will be no longer considered.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn this paper, we employ the Fast Marching Surface Wave Tomography method (Rawlinson and Sambridge, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) for the inversion of two-dimensional phase and group velocities. Generally, the propagation paths of short-period surface waves deviate from great circle paths, and this method takes into account the bending effect of surface wave ray paths, making it more suitable for shallow crustal studies. The checkerboard test can evaluate the ability of the tomography method to resolve velocity anomalies at different scales. We chose a grid division of 0.02\u0026deg; \u0026times; 0.01\u0026deg;, with velocity perturbations set at \u0026plusmn;\u0026thinsp;3%. Despite the relatively small number of stations in this study, the recovery results indicate that the anomalous body can still be recovered in most areas (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Therefore, we choose to invert for the pure-path dispersions and two-dimensional velocity maps of Rayleigh and Love waves with different periods under this grid (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAccording to the pure path dispersions obtained at different grid points, we employed linear iterative inversion program (surf96) to obtain the one-dimensional S-wave velocity structure below each grid point. Furthermore, we need to construct an initial model for the inversion process, as an initial model that is closer to the real model can ensure the reliability of the inversion results. This study refers to the conversion formula of surface wave velocity and wavelength proposed by previous studies (Liu et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Suemoto et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), which involve multiplying the phase velocity measured at a depth of one-third of the wavelength by 1.1, and using the approximate converted average shear wave velocity as the initial model (Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea-b). In addition, the values of P wave velocity and density required by the initial model are calculated by the Nafe-Drake empirical formula (Brocher, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). During the inversion process, the thickness of each layer is set to 0.1 km. Based on the depth sensitivity kernel for the velocity dispersion of Rayleigh and Love waves at different periods that we have calculated (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e), it is appropriate to set the inversion depth above 2 km. Therefore, by combining the group velocity and phase velocity dispersions of Rayleigh waves, we inverted the one-dimensional SV wave velocity structure beneath each grid point. By independently inverting the pure-path dispersions of Love wave group velocity, we obtained the one-dimensional SH wave velocity structure. Finally, we combined the velocity structures of all grid points within the study area and used linear interpolation to obtain the 3-D SV and SH wave velocity structures (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. H/V spectral ratio\u003c/h2\u003e \u003cp\u003eThe Horizontal-to-Vertical Spectral Ratio is a passive seismological method for evaluating site seismic response. It estimates the resonance frequency (HVSR peak frequency or period) and site amplification factor by measuring the spectral ratio of horizontal to vertical components of ambient noise signals. The basic calculation formula for the HVSR method is as follows:\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:HVSR\\left(f\\right)=\\frac{\\sqrt{{\\left|{H}_{x}\\left(f\\right)\\right|}^{2}+{\\left|{H}_{y}\\left(f\\right)\\right|}^{2}}}{\\left|V\\left(f\\right)\\right|}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}_{x}\\left(f\\right)\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}_{y}\\left(f\\right)\\)\u003c/span\u003e\u003c/span\u003e are the Fourier amplitudes of the horizontal components \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:x\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:y\\)\u003c/span\u003e\u003c/span\u003e at frequency \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:f\\)\u003c/span\u003e\u003c/span\u003e, respectively, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:V\\left(f\\right)\\)\u003c/span\u003e\u003c/span\u003e is the Fourier amplitude of the vertical components at frequency \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:f\\)\u003c/span\u003e\u003c/span\u003e. In practical applications, the recorded ambient noise signals are typically preprocessed. We segment the three-component continuous waveform data into 400-second time windows with a moving step of 200 seconds. By applying filtering and smoothing techniques, a clear HVSR curve is extracted (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e8\u003c/span\u003e). The peak frequency of the HVSR curve is generally regarded as the resonance frequency of the site, while the peak amplitude is related to the site amplification factor. Thus, the thickness \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:h\\)\u003c/span\u003e\u003c/span\u003e of bedrock can be inferred from the fundamental resonance frequency \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\:f}_{0}\\)\u003c/span\u003e\u003c/span\u003e of the HVSR curve (Seht and Wohlenberg, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Parolai et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). The relationship is given as follows:\u003c/p\u003e \u003cp\u003e \u003cdiv id=\"Equ2\" class=\"Equation\"\u003e \u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:h=\\frac{{V}_{s}}{4{f}_{0}}$$\u003c/div\u003e \u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003ewhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{V}_{s}\\)\u003c/span\u003e\u003c/span\u003e is the average S-wave velocity of the sedimentary layer. Since the study area is located on sparsely populated Antarctic islands, there are no related imaging results yet that can distinguish the S wave velocity structure at the shallow surface. Therefore, here we adopt the empirical relational formula proposed by previous researchers (Seht and Wohlenberg, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1999\u003c/span\u003e), which is as follows:\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:h=a{f}_{0}^{b}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:a\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:b\\)\u003c/span\u003e\u003c/span\u003e are constants determined through data fitting of soil-rock interface depth calibrated by borehole and picked peak frequency. Due to the lack of borehole data in this area, we choose h\u0026thinsp;=\u0026thinsp;96\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{f}_{0}^{-1.388}\\)\u003c/span\u003e\u003c/span\u003e(Parolai et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2002\u003c/span\u003e) to estimate the bedrock thickness of Fildes Peninsula.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Group velocity structure\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the horizontal distribution of the group velocities of Rayleigh and Love waves with periods of 0.5, 1.0 and 1.5 s. At a shorter period of 0.5 s (Figs.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea and d), the results of Rayleigh wave and Love wave group velocities are relatively consistent. The low-velocity bodies are mainly distributed in Agate Beach and the northeast of Ardley Cove, while Fossil Hill area mainly exhibits high-velocity anomalies. At the period of 1.0 s, the group velocities of Rayleigh wave near Agate Beach show obvious low-velocity anomalies (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb), while the low-velocity zones of Love wave are mainly distributed in the western side of Jasper Mountain and the northern part of Ardley Cove, the high-velocity anomalies are shown in the area from Fossil Hill to Block Hill (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ee). At the period of 1.5 s, the group velocities of Rayleigh wave (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec) reveal that the area from Block Hill to Ardley Cove exhibiting obvious high-velocity anomalies, and the western part of the peninsula with faults shows low-velocity characteristics. The group velocities of Love wave are consistent with that of the Rayleigh wave, but there are still some low-velocity anomalies in the northern Ardley Cove (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ef).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Near-surface structures assessment from HVSR\u003c/h2\u003e \u003cp\u003eBy normalizing the amplitude of stations, the HVSR resonance frequency distribution and calculated thickness distribution at the shallow surface of Fildes Peninsula are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003e. We can see that the peak of resonance frequency for each station is basically above 10 Hz, and the average depth of sedimentary layers is within 5 m according to the formula transformation. For the stations near Fossil Hill and Block Hill (e.g., CC20, CC19, CC17), which are all at elevation depths of 90 m or more, the stratigraphy beneath them may not contain sedimentary layers. The thickness of the sedimentary layer beneath some of the stations along the coast (CC04, CC12, CC02) is relatively more pronounced.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eUsing ambient noise tomography and the HVSR methods can provide useful information for exploring the sedimentary environment of Fildes Peninsula. As an island primarily composed of volcanic rocks, the Fildes Peninsula underwent two magmatic differentiation processes during its formation, with its surface predominantly covered by high-alumina basalts and basaltic andesites (Li et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Zheng et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). The rock composition of volcanic islands is typically closely related to volcanic activity, thus their formation background differs from that of continental crust, and the rock composition primarily originates from magma, volcanic ash, and volcanic debris produced by volcanic eruptions. According to the HVSR of 23 stations, the peak frequencies are mainly distributed between 10 Hz and 50 Hz (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003ea), whereas the site resonance frequencies in continental areas are usually lower than 10 Hz (Ma et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Qin et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The shallow development of the sedimentary layer below the station can also be seen by the calculation of the frequency-depth conversion formula (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e9\u003c/span\u003eb). Based on the spatial distribution of stations, the sedimentary layers along the coast of the peninsula are relatively thicker compared to those in the central region. For example, the resonance frequencies beneath both the station CC04 located on the riverbank and the station CC12 positioned at the edge of the ice sheet are relatively low, which we believe may be related to the formation of certain accumulation layers at the lower elevation coastal area under the influence of various dynamics such as rivers, waves, tides. In addition, the analysis of samples collected in the southeast corner of the peninsula by previous researchers (Shen, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1992\u003c/span\u003e) revealed that this area is mainly composed of volcanic breccia, tuff, tuffaceous sandstone and tuffaceous mudstone, possibly representing lacustrine deposits near the coast with a thickness of approximately 5.5 meters, which further corroborates our findings.\u003c/p\u003e \u003cp\u003eDue to the constraints of geographical location and climatic conditions, there are relatively few tomography studies on Antarctica at present. Current imaging results in this area mainly focus on construction of large-scale three-dimensional velocity models to explore the crust-mantle deformation characteristics such as Bransfield Basin and South Shetland Trench (Li et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Muhumuza, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The three-dimensional shear wave velocity model of the shallow crust of Fildes Peninsula obtained in this paper can provide a new imaging basis for the study of regional tectonic and deformation (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e10\u003c/span\u003e), and reveal the anisotropic characteristics of the shallow crust. At a depth of 0.6 km, there is a consistency between the velocity structure and the fault distribution. The SV and SH waves in the fault distribution area on the southwest side of the peninsula mostly show low-velocity anomalies, with this feature being more prominent in the SH wave velocity structure. Additionally, low-velocity anomalies are also distributed in the northern part of Ardley Cove. At a depth of 1.2 km, the area from Fossil Hill to Block Hill mainly exhibits high-velocity anomalies, indicating its relatively stable crustal structure. At a greater depth of 1.8 km, there are certain differences in SV and SH wave velocities. Specifically, the SH waves in the Agate Beach and the eastern part of Jasper Hill mainly show low-velocity structures, while the low-velocity areas for SV waves are primarily distributed around Jasper Hill. The high-velocity anomalies are mainly distributed in the area from Ardley Cove to Block Hill. It can be observed from the distribution of peninsula faults that there are several NW and NWW faults distributed in Agate Beach and Jasper Hill, and rock fragmentation, fracture development and possible fluid filling in the fault zone will increase the propagation path of waves, which will make the propagation velocity of S waves decay faster (Liang et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Ma et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In addition, lithological characteristics and isotopic geochemical studies of the exposed igneous rocks (Li et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1992\u003c/span\u003e) indicate a trend of gradually younger volcanic rock ages from southwest to northeast on Fields Peninsula. The first stage is dated to the Paleocene, with volcanic eruption centers concentrated in the Jasper Hill and Agate Beach sections. The second stage is dated to the Eocene, with volcanic eruption centers distributed more dispersedly in the Fossil Hill and Block Hill. Our velocity structure corresponds well with the volcanic rock ages. Due to earlier volcanic activity in the southwest, subsequent magma intruded along the NW and NWW regional fractures on the western side of the peninsula. After undergoing prolonged weathering and erosion, the density and rigidity of the shallow igneous rocks were weakened, resulting in lower velocity structures. In the area from Fossil Hill to Block Hill, the shear wave velocity structures show high-velocity anomalies due to relatively young metamorphic rocks on the surface and shallow underground.\u003c/p\u003e \u003cp\u003eThe vertical profile slices allow the study of the depth-influenced range of 3-D velocity structures. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e, there is a positive correlation between the velocities and depth of both SV waves and SH waves. It is noteworthy that there exists a low-velocity layer with a depth of approximately 1 km in the northern part of Ardley Cove. The factors influencing shallow velocity anomalies are not only related to material composition, porosity, and water content, but also to fault structures (Nimiya et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). It can be seen from the geological map of Fildes Peninsula (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec), there are mainly breccia of Fossil Hill Member, tuff and pyroclastic rocks in this area. Furthermore, the sedimentary environment in this region differs from the lacustrine sediments on the southeast side of the peninsula, belonging to small-scale intermontane basin accumulation (Shen, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1992\u003c/span\u003e). This area also corresponds to the southeast segment of the largest fault on the peninsula, which may have further cut through the shallow crust. Therefore, volcaniclastic sedimentary rocks, along with the overlying layers and NWW trending faults, may be the causes of low-velocity anomalies. By comparing the velocities of SV waves and SH waves, we find that the shallow crust of Fildes Peninsula mainly exhibits negative radial anisotropy, which aligns with the characteristics of the shallow subsurface in volcanic regions (Lee et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mordret et al., 2014). Negative radial anisotropy may arise from the alteration of the oriented arrangement of fluid-bearing microfractures and pores due to crustal stress induced by the upward movement of magma prior to volcanic eruptions, further affecting the propagation characteristics of seismic waves. In summary, we believe that the shallow crustal medium structure of Fildes Peninsula exhibits significant inhomogeneity, and the distribution of velocity anomalies has a strong correlation with surface geological structures. Due to the relatively limited number of seismic stations, this study discusses the shallow medium structure and dynamic mechanisms of Fildes Peninsula within the maximum range of station distribution, the resolution in the marginal areas may not be ideal. In the future, it is expected that more seismic stations will be deployed to conduct higher-resolution and more in-depth research on the island.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eIn this study, we utilized continuous waveform data recorded by short-period dense array on Fildes Peninsula to conduct ambient noise tomography and HVSR analysis, obtaining the characteristics of the shallow crust structure in this region. Our results indicate that the near-surface sedimentary layers on the peninsula are very shallow, with thicker layers near the coast compared to the center of the island. Additionally, the three-dimensional S-wave velocity structure exhibits a strong correlation with the surface geological structures and reveals the inhomogeneity of the shallow crustal medium in this area. The metamorphic rocks formed during earlier volcanic activity have lower velocities than those formed during later periods, and fault structures also locally influence shallow crustal velocity anomalies. By comparing the velocity structures of SV waves and SH waves, the shallow layer of the study area mainly exhibits negative radial anisotropy, which accords with the characteristics of shallow subsurface activity in volcanic regions.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eS.H. wrote the main manuscript text. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eWe acknowledge the efforts of staff involved in the Chinese 40th Antarctic Scientific Expedition Team in collecting the data used in this study. This study was supported by the National Natural Science Foundation of China (grant number 42374079), the Special Fund of the Institute of Geophysics, China Earthquake Administration (grant numbers JY2023Z01). Most figures were made using Generic Mapping Tools (GMT).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlmendros, J., Wilcock, W., Soule, D., Teixid\u0026oacute;, T., Vizca\u0026iacute;no, L., Ardanaz, O., Granja-Bru\u0026ntilde;a, J.L., Mart\u0026iacute;n-Jim\u0026eacute;nez, D., Yuan, X., Heit, B., Schmidt-Aursch, M.C., Geissler, W., Dziak, R., Carri\u0026oacute;n, F., Ontiveros, A., Abella, R., Carmona, E., Ag\u0026uuml;\u0026iacute;-Fern\u0026aacute;ndez, J.F., S\u0026aacute;nchez, N., Serrano, I., Davoli, R., Krauss, Z., Kidiwela, M., Schmahl, L., 2020. BRAVOSEIS: Geophysical investigation of rifting and volcanism in the Bransfield strait, Antarctica. 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Chinese Journal of Polar Research 3 (2), 126\u0026ndash;135 (in Chinese with English abstract). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://journal.chinare.org.cn/CN/Y1991/V3/I2/126\u003c/span\u003e\u003cspan address=\"https://journal.chinare.org.cn/CN/Y1991/V3/I2/126\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\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":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pure-and-applied-geophysics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"paag","sideBox":"Learn more about [Pure and Applied Geophysics](https://www.springer.com/journal/24)","snPcode":"24","submissionUrl":"https://submission.nature.com/new-submission/24/3","title":"Pure and Applied Geophysics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Fildes Peninsula, Ambient noise tomography, S-wave velocity, Horizontal-to-vertical spectral ratio","lastPublishedDoi":"10.21203/rs.3.rs-5372490/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5372490/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eFildes Peninsula is the most exposed area of King George Island, Antarctica, which has experienced frequent volcanic activities, and its strata are composed mainly of basalt and pyroclastic rocks, making it an ideal location for conducting scientific research in Antarctica. This study provides the first constraints on the shallow crustal structure of the peninsula through ambient noise tomography and horizontal-to-vertical spectral ratio (HVSR) analyses by utilizing a denser array of short-period portable seismometers deployed on Fildes Peninsula. The results indicate that the sediment layers on the peninsula are very thin and reveal inhomogeneity within the shallow crust of the study area, which may be related to the characteristics of the surface geological structure. Consistent with crustal activity characteristics observed in most volcanically active regions around the globe, the shallow layers in the study area exhibit predominantly negative radial anisotropy. Our results provide an important imaging basis for the study of shallow crustal structure and deformation on Fildes Peninsula.\u003c/p\u003e","manuscriptTitle":"Shallow crustal velocity structure and tectonic significance beneath Fildes Peninsula, West Antarctica","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-01 16:32:23","doi":"10.21203/rs.3.rs-5372490/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-02-10T05:39:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-01-13T15:23:40+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"183440288354687782869289038537188045665","date":"2024-12-28T14:00:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"70582673599273254463773172343185340283","date":"2024-12-10T07:13:18+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-12-08T06:02:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-11-02T15:03:47+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-11-02T14:50:41+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pure and Applied Geophysics","date":"2024-11-01T09:56:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pure-and-applied-geophysics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"paag","sideBox":"Learn more about [Pure and Applied Geophysics](https://www.springer.com/journal/24)","snPcode":"24","submissionUrl":"https://submission.nature.com/new-submission/24/3","title":"Pure and Applied Geophysics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"80cecf4d-a4be-4a9a-97cd-171a8c50cdbf","owner":[],"postedDate":"December 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-04-14T16:09:27+00:00","versionOfRecord":{"articleIdentity":"rs-5372490","link":"https://doi.org/10.1007/s00024-025-03712-3","journal":{"identity":"pure-and-applied-geophysics","isVorOnly":false,"title":"Pure and Applied Geophysics"},"publishedOn":"2025-04-09 16:05:22","publishedOnDateReadable":"April 9th, 2025"},"versionCreatedAt":"2024-12-01 16:32:23","video":"","vorDoi":"10.1007/s00024-025-03712-3","vorDoiUrl":"https://doi.org/10.1007/s00024-025-03712-3","workflowStages":[]},"version":"v1","identity":"rs-5372490","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5372490","identity":"rs-5372490","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}