THE 2005 NOVEMBER 27 QESHM ISLAND EARTHQUAKE (IRAN), MW 6.0, AFTERSHOCK SEISMICITY

From 2005 December 2 to 2006 February 26, a dense seismological network of 17 stations was installed in the epicentral region of the 2005 November 27 Qeshm earthquake sequence. Epicentral and depth distribution of the aftershocks is diffuse and it is difficult to define simple alignments related to faults. This implies that different faults had involved creating such diffuse pattern. However depth distribution of selected events in eastern end of the aftershock zone reveals one alignment trending NW with ~45º dip. Upper limit for depth is close to 20 km that is more than other calculated depths in the Zagros by local networks. Pattern of the calculated focal mechanisms indicates two families of mechanisms: strike-slip and reverse mechanisms. This complexity can be explained by two scenarios: the first one that is compatible with geological observation is triggering of the right-lateral strike-slip fault in NW-SE direction because of the energy release of the reverse fault that is not supported well by distribution of aftershock seismicity. Another explanation could be that deformation in western edge of the Hormoz strait is accommodated by partitioning between the strike-slip and reverse faulting.