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Sequence signal processing of 2012 Ahar–Varzaghan earthquake (M W 6.4) of NW Iran

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Abstract

Before starting seismic cycle of Ahar–Varzaghan 2012 event, a partial gap in the form of a pre-seismic calm sequence (seismicity rate, r = 0.46 event/year, b = 1.4) with duration of 303 days spatially has dominated over the entire seismogenic area. From April 17, 2012, to May 31, 2012, r significantly increased to 2.16, indicating strong foreshock sequence, and b value changed to 1.9, remarkably. In the last two months before the mainshock, foreshocks have partially migrated toward the earthquake fault (with a decrease in size, b = 2.0). Significantly, high rate of seismicity and low V P /V S (1.64) in the foreshocks sequence and also very high seismicity rate (17.3) and high V P /V S (1.76) in the aftershocks sequence make substantial differences between the seismic cycle and the background seismicity. Moreover, a significant E–W migration of the microseismicity was confirmed in the study area.

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Acknowledgements

Thanks to the Institute of Geophysics, the University of Tehran, for their online recent earthquake catalog (2006 to 2015).

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  1. Department of Geology, Faculty of Science and Earthquake Research Center, Shahid Bahonar University of Kerman, Pajouhesh Sq., Kerman, Iran

    Majid Nemati

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Nemati, M. Sequence signal processing of 2012 Ahar–Varzaghan earthquake (M W 6.4) of NW Iran. Environ Earth Sci 76, 495 (2017). https://doi.org/10.1007/s12665-017-6832-1

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