Microseismicity and focal mechanisms at the western termination of the North Anatolian Fault and their implications for continental tectonics

Abstract

For seven weeks, a temporary network of 68 seismological stations was operated in Central Greece, in the region of Thessaly and Evia, located at the western termination of the North Anatolian Fault system. We recorded 510 earthquakes and computed 80 focal mechanisms. Seismic activity is associated with the NE–SW dextral North Aegean Fault, or with very young E–W-striking normal faults that are located around the Gulf of Volos and the Gulf of Lamia. The important NW–SE-striking faults bounding the Pilion, or the basins of Larissa and Karditsa, are not seismically active, suggesting that it is easier to break continental crust, creating new faults perpendicular to the principal stresses, than to reactivate faults that strike obliquely to the principal stress axes