A lower-crustal event in the northeastern Mediterranean: The 1998 Adana Earthquake (M-w=6.2) and its aftershocks

We analyse the main and aftershocks of the June 27, 1998 Adana earthquake u sing data from the short-period Cilician seismograph network in order to in vestigate the seismotectonics of the northeastern Mediterranean region. The mainshock is found to have a pure left lateral strike-slip mechanism (stri ke=50(0), dip=85(0), rake=10(0), M-0=3.63x10(18) Nm). The inferred strike d irection of 50(0) N closely aligns with the surface trend of the Goksun Fau lt Zone (GFZ). The depth and size of the mainshock and the distribution of the aftershocks indicate that the rupture nucleated within the lower crust, and did not extend to shallower zones. This seismicity pattern indicates t hat these events are associated with actively interacting African and Anato lian lithospheres in a strike-slip manner at depth. Thus, we propose that t he southern segment of the GFZ belongs to the diffuse Africa-Anatolia plate boundary and plays a major role in the plate kinematics of the northeaster n Mediterranean.