Source Parameters and Rupture Process in the Extensional Stress Regime of Central Greece; Implications from the August 2013 Moderate Size Earthquake Sequence.

Abstract:

The August 2013 Mw 5.4 seismic sequence which occurred in Kallidromon Mountain (central Greece) and its relation to the 2008 adjacent sequence are investigated. Both sequences though moderate in size, produced severe damage in the nearby villages. We use broadband waveform data to study the source parameters and the rupture process of the 2013 seismic events. We use the TR method to identify the real seismogenic fault plane of the sequence. We compare the characteristics of the 2013 sequence with those of the 2008, and calculate the static stress changes to identify the interactions between adjacent segments. The WSW-ESE strike of the earthquake epicenters of the 2013 sequence is in accordance with the strike of the major normal faults of the area that as a rule dip to the NNE. On the contrary, the focal mechanisms of the 2013 events identify a seismogenic fault of normal type that dip to the south and stands as an antithetic fault. In addition, the extensional stress regime is further investigated using the information provided from the focal mechanisms of the two sequences.