A detailed source study of the Orta (Cankiri) earthquake of June 6, 2000 (M-S=6.1): An intraplate earthquake in central Anatolia

Abstract

The devastating. Izmit and Duzce earthquakes were followed by the Orta intra-plate earthquake (M-S = 6.1) occurred in the central Anatolian block on June 6, 2000. The focal mechanism, aftershock distribution and the field studies (Emre et al., 2000) suggest a movement on a 21-km long Dodurga fault striking nearly N-S where the sense of motion is left-lateral strike-slip with considerable amount of normal component. We applied the constrained linear finite-fault inversion method of Hartzell and Heaton (1983) to the teleseismic P and SH waveforms to derive a coseismic slip distribution model for the earthquake. Time windows approach is applied allowing variable rise times and rupture velocities. The source-rise time function is discretized into consecutive time intervals that stand for slip contribution of individual subfaults. Although no clear surface ruptures were associated with the earthquake, the resulting slip model suggests coseismic slip in the order of several tens of centimetres. Our coseismic slip distribution model identifies two slip patches with the following maximum slip values: (1) the larger one (42 cm) is located to the south of the hypocenter at depth range of 4-8 km and (2) the smaller one (31 cm) is located just above and north of the hypocenter. The slip-model yield a seismic moment of 1.0 x 10(18) Nm, most of which is released from the rupture over the depth of 8 km.