TITLE:
Statistical Properties of Aftershocks for Ahar-Varzeghan Twin Earthquakes on 11 August 2012, NW Iran, and Investigation of Seismicity of North Tabriz Fault
AUTHORS:
Jamileh Vasheghani Farahani
KEYWORDS:
Ahar-Varzeghan Twin Earthquakes, Aftershocks, B-Value, Modified Omori Law, Azerbaijan Province
JOURNAL NAME:
International Journal of Geosciences,
Vol.9 No.2,
February
26,
2018
ABSTRACT:
Two earthquakes occurred on 11 August 2012 in East Azerbaijan province,
NW Iran with Mw 6.3 at 12:23:15.9 and Mw 6.1; 11 minutes after the first
shock at 12:34:34.8 GMT time. In this study, we concentrated on the properties
of the aftershock sequences in a duration of 7.5-month time-period data
after the main shocks, recorded by Broadband Iranian Network (BIN). We
obtained p, c and K parameters with the maximum likelihood method and the
occurrence rate was modeled by the modified Omori formula. Besides, we
showed that aftershocks of the aftershock in 7 Nov. 2012 (M = 5.6) also decay
according to the modified Omori law. We investigated the spatial and temporal
variations of b-values before and after the twin earthquakes with Mw 6.3
and Mw 6.1 approximately 20 km around North Tabriz Fault (NTF) in the region
from 1996 to 2013 using Iranian Seismological Center (IRSC). We believed
that a research of the past 17 years has clearly established that spatial
b-value changes and seismicity rate are highly significant and meaningful.
Moreover, our research led to a warning for a probable strong motion along
NTF for the coming couple of years.