1 / 29

Regional seismicity as a flow of clusters: A case study in California and Nevada

Regional seismicity as a flow of clusters: A case study in California and Nevada. Ilya Zaliapin & Jennifer Bautista. Department of Mathematics and Statistics University of Nevada, Reno. Thanks to: John Anderson, Iain Bailey, Yehuda Ben-Zion, Andrew Hicks, Peter Powers, and Zhigang Peng.

opal
Download Presentation

Regional seismicity as a flow of clusters: A case study in California and Nevada

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Regional seismicity as a flow of clusters: A case study in California and Nevada Ilya Zaliapin & Jennifer Bautista Department of Mathematics and Statistics University of Nevada, Reno Thanks to: John Anderson, Iain Bailey, Yehuda Ben-Zion, Andrew Hicks, Peter Powers, and Zhigang Peng SSA Annual Meeting * Friday, April 23, 2010

  2. Outline Earthquake clustering: existence and detection 1 1 Seismicity as a flow of clusters 2 2 Non-aftershock clustering: Swarms 3 3 Summary 4 4

  3. Earthquake cluster analysis Baiesi and Paczuski, PRE, 69, 066106 (2004) Zaliapin et al., PRL, 101, 018501(2008)

  4. Expected number of EQs with magnitude m (Fractal) dimension of epicenters Intercurrence time Spatial distance Gutenberg-Richter law Distance between EQs Magnitude m Space Time [M. Baiesi and M. Paczuski, PRE, 69, 066106 (2004)]

  5. Spatio-temporal distribution of neighbors Homogeneous flow (no clusters) Rescaled distance, log R Rescaled time, log T [Zaliapin et al., PRL, 101, 018501(2008)]

  6. Spatio-temporal distribution of neighbors Homogeneous flow (no clusters) Rescaled distance, log R Clusters Rescaled time, log T [Zaliapin et al., PRL, 101, 018501(2008)]

  7. Regions & catalogs analyzed California (1984-present, m ≥ 2.0) ANSS, http://www.ncedc.org/anss/catalog-search.html Southern California (1981-2005, m ≥2.0) Shearer et al. (2005),BSSA, 95(3), 904–915. Lin et al. (2007), JGR, 112, B12309. Parkfield (1984-2005, m > 0.0) Thurber et al. (2006), BSSA, 96, 4B, S38-S49. 25 individual fault zones in CA (1984-2002) Powers and Jordan(2009), JGR, in press. Hauksson and Shearer (2005), BSSA, 95(3), 896–903. Shearer et al. (2005),BSSA,95(3), 904–915. Nevada (1990-present, m ≥1.0) Nevada Seismological Laboratory http://www.seismo.unr.edu/Catalog/search.html World-wide (1973-present, m ≥4.0 ) USGS/NEIC http://earthquake.usgs.gov/earthquakes/eqarchives/epic/epic_global.php

  8. Shearer et al. (2005),BSSA, 95(3), 904–915 70895 events, m ≥ 2

  9. Separation of clustered and homogeneous parts Homogeneous part (as in Poisson process) Clustered part: events are much closer to each other than in the homogeneous part

  10. World seismicity, USGS/NEIC m ≥ 4.0; 223,600 events California, Shearer et al. (2005) m ≥ 2.0; 70,895 events Nevada, Nevada SeismoLab m > 1.0; 75,351 events Parkfield, Thurber et al. (2006) m > 0.0; 8,993 events

  11. Seismicity as a flow of clusters

  12. Identification of clusters: data driven Cluster #3 Cluster #1 Cluster #2 weak link strong link

  13. Identification of event types: problem driven Foreshocks Mainshock Aftershocks Time

  14. Declustering at a glance: California

  15. Shearer et al. (2005) catalog: 70895 events, m ≥ 2

  16. Shearer et al. (2005) catalog, m ≥ 2 22537 main + 43384 after + 4974 foreshocks 32% main + 61% after + 7% foreshocks Mainshocks

  17. Shearer et al. (2005) catalog: 70895 events, m ≥ 2 All events Mainshocks

  18. Cluster separation is time- & space-dependent

  19. Cluster statistics

  20. Cluster size distribution P(N >x)  x-g ; g 1

  21. Aftershock productivity ‹Naft(m)›  10am ; a 1

  22. Cluster energy distribution ‹M(m)›  10bm ; b 1.5

  23. A case study in Nevada: Mogul-Somersett sequence of 2008

  24. Nevada, NSL, m ≥ 1.0, 75351 events 21209 (28%) mainshocks 44363 (59%) aftershocks 9770 (13%) foreshocks

  25. Nevada, NSL, m ≥ 1.0, 75351 events 21209 (28%) mainshocks 44363 (59%) aftershocks 9770 (13%) foreshocks Mainshocks

  26. The Mogul-Somersett sequence of 2008 is comprised of a single cluster with mainshock of m = 4.7 and the record number of foreshocks, Nfor = 454. The Nevada mean for m ≥4.7 is 17.2.

  27. Summary Existence of two EQ populations: clustered and homogeneous 1 1 A unified approach to study aftershocks, foreshocks, swarms, etc. Notable deviation from self-similarity Objective non-parametric declustering Seismicity: Flow of clusters 2 2 Non-aftershock clustering: Swarms 3 3 Mogul-Somersett sequence: a sequence with record aftershock/foreshock productivity. 4 4

  28. Thank you!

  29. Average cluster duration ‹Taft(m)›  10qm ; q 1.5

More Related