Imaging supershear rupture for the 2014 M w 6.9 Northern Aegean earthquake by backprojection of strong motion waveforms

The seismic source spatiotemporal evolution of the M w 6.9 event on 24 May 2014 in Northern Aegean is imaged by backprojection of strong motion envelopes. The results indicate that the event ruptured on two different fault segments. In the first one, rupture propagated from the hypocenter westward for ∼20 km. In the second delayed segment to the east, rupture propagated eastward for ∼65 km with a supershear velocity (∼5.5 km/s). At the end of this rupture the largest stacking amplitudes are imaged, associated with possible stopping phases from the abrupt cessation of a fast slip. Low‐aftershock seismicity on the supershear segment implies a simple and linear fault geometry there. This is the third large event in the Northern Aegean Trough‐Northern Anatolian Fault zones that has ruptured with supershear speed. This characteristic should be taken into account in studying past events and estimating seismic hazard in this area. Two distinct rupture segments Eastern segment with supershear rupture High frequency mainly radiates from the end of ruptured segments