Aftershocks of the magnitude Mw 6.4 Bingöl earthquake of 1 May 2003 (eastern Turkey) were monitored by a local temporary seismic network. The spatial distribution of the aftershocks shows that the earthquake did not occur on the left-lateral East Anatolian fault, but perpendicular to it along a north-northwest-striking right-lateral fault. The event ruptured an area of 20 km by 8 km, but did not reach the Earth’s surface. The aftershocks of the 2003 Bingöl earthquake and those of the 1992 Erzincan earthquake seem to indicate the existence of a new seismically active right-lateral shear zone. Indeed, we show that historical earthquakes along both the North and East Anatolian fault led to positive changes in Coulomb failure stress for north-northwest-oriented right-lateral strike-slip faults in the Bingöl epicentral area. Moreover, the existence of such faults is supported by remote-sensing data.
Online material: Fault geometry and aftershock data near Bingöl.