M Mojarab; H Memarian; M Zare; V Kossobokov
Abstract
The earthquake of 23 October 2011, near the Turkish city of Van, had 600 victims and caused great damages in Van, Argis, Moradiyeh and Caldiran. Review of 20th century and historical earthquakes in eastern Anatolian plate and west of Iranian plateau confirmed the activity of this area with the notable ...
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The earthquake of 23 October 2011, near the Turkish city of Van, had 600 victims and caused great damages in Van, Argis, Moradiyeh and Caldiran. Review of 20th century and historical earthquakes in eastern Anatolian plate and west of Iranian plateau confirmed the activity of this area with the notable earthquake of 24 November 1976 in Caldiran. The main objective of this paper is evaluation of predictability of earthquakes in this region. Presently, the two main approaches for predicting extreme events are precursory and pattern recognition algorithms. For this study, we applied M8 algorithm that is based on pattern recognition. In this respect,a 49 point network were designed around the epicenter of Van earthquake and M8 algorithm applied to this network. The end result was four zones with some overlaps that were proposed as CTIP (current time of increase probability). This study could predict the Van earthquake with 1/1/2008 to 30/12/2012 time window, 281 km local radius and magnitude of more than 7. In addition, forward prediction in this area shows there is no alarm for magnitude 7+ in next 5 years. This study showed the strength of M8 algorithm for predicting earthquakes in the Middle East. It can be concluded that using algorithms based on pattern recognition can play an important role for mitigation of damages in seismic events.
Kh. Hessami Azar; Kh. Motaghi; M. Mostafazadeh
Abstract
In this study, we estimated a local seismic hazard map for the Alborz tectonic region located in north of Iran. The technique of mapping local recurrence time, TL, was used to map major asperities of the region and the asperities considered as the area with maximum hazard probability. The analysis was ...
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In this study, we estimated a local seismic hazard map for the Alborz tectonic region located in north of Iran. The technique of mapping local recurrence time, TL, was used to map major asperities of the region and the asperities considered as the area with maximum hazard probability. The analysis was done on the epicenter of more than 5000 events recorded in 19 stations of the Institute of Geophysics, University of Tehran (IGUT), during 1996-2008. Based on the idea that b-value is inversely related to applied stress, we calculated local b-values for each grid and areas with lowest b- and a-values, and as a result shortest TL were interpreted as asperities. Because the ruptures start from the asperities, the mentioned regions have considered as the region with the maximum seismic hazard. The rupture location of MW 6.3 Kojour-Firooz Abad earthquake compared to the recurrence time map and it resulted in the location of this event had showed anomalously short TL based on the background seismicity of region in a decade before it. We computed TL map based on the seismicity before and after Kojour-Firooz Abad earthquake and showed that this large event redistributed the applied stress in the Alborz region. Redistribution by large earthquake led to migration of the applied stress from west of region to east. Based on the microseismicity of the region after Kojour-Firouz Abad earthquake, there are three anomalies in TL map positioned in eastern Alborz. These anomalies are introduced as the regions with maximum seismic hazard for future large earthquake.