Foreshocks and Their Potential Deviation from General Seismicity
2018; Seismological Society of America; Volume: 109; Issue: 1 Linguagem: Inglês
10.1785/0120170188
ISSN1943-3573
AutoresStefanie Seif, J. D. Zechar, Arnaud Mignan, Shyam Nandan, Stefan Wiemer,
Tópico(s)High-pressure geophysics and materials
ResumoResearch Article| December 04, 2018 Foreshocks and Their Potential Deviation from General Seismicity Stefanie Seif; Stefanie Seif aSwiss Seismological Service (SED), ETH Zürich, No. H 51.3, Sonneggstrasse 5, 8092 Zürich, Switzerland, stefanie.seif@sed.ethz.ch Search for other works by this author on: GSW Google Scholar Jeremy Douglas Zechar; Jeremy Douglas Zechar bAXIS Re, Alfred Escher‐Strasse 50, 8002 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Arnaud Mignan; Arnaud Mignan cInstitute of Geophysics, No. H 66, Sonneggstrasse 5, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Shyam Nandan; Shyam Nandan aSwiss Seismological Service (SED), ETH Zürich, No. H 51.3, Sonneggstrasse 5, 8092 Zürich, Switzerland, stefanie.seif@sed.ethz.ch Search for other works by this author on: GSW Google Scholar Stefan Wiemer Stefan Wiemer dSwiss Seismological Service (SED), No. H 61, Sonneggstrasse 5, 8092 Zürich, Switzerland Search for other works by this author on: GSW Google Scholar Author and Article Information Stefanie Seif aSwiss Seismological Service (SED), ETH Zürich, No. H 51.3, Sonneggstrasse 5, 8092 Zürich, Switzerland, stefanie.seif@sed.ethz.ch Jeremy Douglas Zechar bAXIS Re, Alfred Escher‐Strasse 50, 8002 Zürich, Switzerland Arnaud Mignan cInstitute of Geophysics, No. H 66, Sonneggstrasse 5, 8092 Zürich, Switzerland Shyam Nandan aSwiss Seismological Service (SED), ETH Zürich, No. H 51.3, Sonneggstrasse 5, 8092 Zürich, Switzerland, stefanie.seif@sed.ethz.ch Stefan Wiemer dSwiss Seismological Service (SED), No. H 61, Sonneggstrasse 5, 8092 Zürich, Switzerland Publisher: Seismological Society of America First Online: 04 Dec 2018 Online Issn: 1943-3573 Print Issn: 0037-1106 © Seismological Society of America Bulletin of the Seismological Society of America (2019) 109 (1): 1–18. https://doi.org/10.1785/0120170188 Article history First Online: 04 Dec 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Stefanie Seif, Jeremy Douglas Zechar, Arnaud Mignan, Shyam Nandan, Stefan Wiemer; Foreshocks and Their Potential Deviation from General Seismicity. Bulletin of the Seismological Society of America 2018;; 109 (1): 1–18. doi: https://doi.org/10.1785/0120170188 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract It is still debated whether earthquake occurrence can be described as a single process or whether foreshocks are different phenomena. If foreshocks behaved differently, this would suggest a change of physical processes in the mainshock preparation phase that would boost hopes of forecasting large earthquakes. Most research on foreshocks focuses on case studies or uses global datasets in which recordings of small earthquakes are incomplete and are thus neglected. We do comprehensive foreshock statistics on all mainshocks in a regional earthquake catalog that is complete above M 2.5. To detect possible differences between foreshocks and seismicity that follows a uniform triggering model (the epidemic‐type aftershock sequence [ETAS] model), we perform a null‐hypothesis test. We also estimate the size of the differences between observed and ETAS‐simulated foreshocks.We define different sets of foreshocks using two different methods, because there is no unique definition: a nearest‐neighbor declustering technique (Zaliapin et al., 2008) and a variety of space–time windows (e.g., Agnew and Jones, 1991). We use data from southern California, northern California, and Italy. For each region, we first search an appropriate null model: an ETAS model that describes aftershock numbers well. In southern California, we find an appropriate spatiotemporal model that is characterized by a large productivity parameter α. After performing a null‐hypothesis test for different mainshock and foreshock magnitudes, we find foreshock signals (p<0.05) for all mainshocks sizes and independent of the foreshock's lower magnitude threshold. Observed mainshocks have more foreshocks than the ETAS model predicts. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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