Aftershock analysis and forecasting for the crustal seismicity in Romania

Aftershock analysis and forecasting for the crustal seismicity in Romania | 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 Aftershock analysis and forecasting for the crustal seismicity in Romania Cristian Ghita, Bogdan Enescu, Alexandru Marinus, Iren-Adelina Moldovan, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4799375/v2 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Apr, 2025 Read the published version in Earth, Planets and Space → Version 2 posted 3 You are reading this latest preprint version Show more versions Abstract Romania is known for its persistent seismicity at intermediate-depths in the Vrancea region, however crustal areas are also a significant source of seismic hazard, although large shallow events are less common. This study is a first attempt to characterize statistically and propose a forecasting model for two recent aftershock sequences occurred at crustal depths in 2014 and 2023, following mainshocks of moderate magnitudes (M w 5.4 for both mainshocks). We apply a robust approach based on a state-of-the-art procedure developed and tested previously for Japan, which is able to determine in quasi real-time the parameters of the Gutenberg-Richter law and Omori-Utsu law for aftershocks and provide probability estimates of larger events, which can be updated in real time. For both the 2014 Vrancea-Marasesti and 2023 Gorj-Oltenia sequences we test several relatively short (hours to day) learning periods and subsequent forecasting periods. Both sequences are characterized by a Gutenberg-Richter b -value around 0.8–0.9, which is only slightly lower than the average of 1.0 for wordwide seismicity. The aftershock decay is characterized by a parameter p of around 1.0, commonly observed for crustal aftershock sequences. The c -value, which indicates the onset time of the power-law decay of aftershocks, is on the order of minutes to hours. Although the two studied sequences follow mainshocks having the same magnitude, the probability of larger aftershocks for the 2023 Gorj-Oltenia sequence are larger. The results obtained in this study are encouraging for the development of a real-time monitoring and forecasting system for the Romanian crustal seismicity. real time aftershock forecasting seismic sequences crustal seismicity Romania Full Text Cite Share Download PDF Status: Published Journal Publication published 11 Apr, 2025 Read the published version in Earth, Planets and Space → Version 2 posted Reviewers agreed at journal 03 Feb, 2025 Editor assigned by journal 31 Jan, 2025 First submitted to journal 27 Jan, 2025 You are reading this latest preprint version Show more versions 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-4799375","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":410649369,"identity":"89b03b59-7d90-41c9-b147-1c776f71dc24","order_by":0,"name":"Cristian Ghita","email":"","orcid":"","institution":"NIEP: Institutul National de Cercetare-Dezvoltare pentru Fizica Pamantului","correspondingAuthor":false,"prefix":"","firstName":"Cristian","middleName":"","lastName":"Ghita","suffix":""},{"id":410649370,"identity":"fec9823e-4df4-432d-a0b7-e2347c89c45d","order_by":1,"name":"Bogdan 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This study is a first attempt to characterize statistically and propose a forecasting model for two recent aftershock sequences occurred at crustal depths in 2014 and 2023, following mainshocks of moderate magnitudes (M\u003csub\u003ew\u003c/sub\u003e5.4 for both mainshocks). We apply a robust approach based on a state-of-the-art procedure developed and tested previously for Japan, which is able to determine in quasi real-time the parameters of the Gutenberg-Richter law and Omori-Utsu law for aftershocks and provide probability estimates of larger events, which can be updated in real time. For both the 2014 Vrancea-Marasesti and 2023 Gorj-Oltenia sequences we test several relatively short (hours to day) learning periods and subsequent forecasting periods. Both sequences are characterized by a Gutenberg-Richter \u003cem\u003eb\u003c/em\u003e-value around 0.8\u0026ndash;0.9, which is only slightly lower than the average of 1.0 for wordwide seismicity. 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