Spatial Distribution of b-value over the rupture zone of 2012 August 11th Ahar earthquake: A detour to distinguish the major shocks

On August 11th, a double earthquake of magnitudes 6.5 and 6.2 Mn hit Azerbaijan province leaded to approximately 400 deaths over the region near to Ahar, Varzaghan and Heris. First mainshock had a pure strike-slip mechanism and the second one also had a thrust component of faulting in addition, based on USGS report. After about three months of initiation of the sequence, another mainshock came into the scene in the west and made damages to the neighbor regions. In this study, the sequence is more comprehensively examined and also we reach a way to distinguish mainshocks from subevents based on b-value, completeness magnitude (Mc) and earthquake density maps. First, recorded events are relocated using nonlinear method of Alomax et al (2000) and then b-value, Mc and earthquake density distribution over the selected region are modeled both horizontally and in depth. Thereafter, conclusions are made upon the results, and the problem of how the seismicity of the sequence is allocated both horizontally and vertically is inspected in detai