Spatial and Temporal Variations of Aftershock Activity of the 23 October 2011 Mw 7.1 Van, Turkey, Earthquake
Abstract
A Mw 7.1 earthquake struck on October 23, 201 the Van Lake region causing vast damage in the cities of Van and Ercis, in Eastern Turkey. The main shock was followed by a very high number of aftershocks: in the first week 114 earthquakes occurred with magnitudes between 4.0 and 4.9 and 7 earthquakes with magnitudes greater than ML 5.0. Within the first month, daily average number of aftershock was around 180 for earthquakes ML>2.0. By 09 December 2011, a total of 6284 aftershocks were recorded by the Prime Ministry Disaster and Emergency Management Presidency (AFAD) permanent network. In this study we take an advantage of this large dataset to examine the spatial and temporal properties of the Van earthquake aftershock activity. In order to do so earthquakes are relocated with the computer code HYPOELLIPSE (Lahr and Snoke, 2001) and a 1D velocity model optimized for the region. The distribution of the relocated aftershocks, with ML >2.5 defines a clear 60-70 km long and 30-35 km wide NE-SW trending structure which is an agreement with the source rupture models derived for the main event. We then derive the spatial distribution of b-value of the Gutenberg-Richter law—as well as complementary seismicity parameters—along the surface projection of the fault plane. Calculations are made for two independent aftershock sub-catalogs before and after where a stable magnitude of completeness is reached. Finally, we correlate the observed b-value patterns with slip distribution models of the main shock obtained through the inversion of seismological and geodetic data.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.S41B2428D
- Keywords:
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- 7223 SEISMOLOGY / Earthquake interaction;
- forecasting;
- and prediction;
- 7230 SEISMOLOGY / Seismicity and tectonics