Investigation of rupture history of the May 1, 2003 Bingöl earthquake obtained from the finite-fault inversion of the teleseismic P and SH wavefroms

Teleseismicaly recorded P and SH velocity waveforms of the 1 May 2003 Bingöl earthquake are inverted to obtain finite-fault slip distribution model. A linear finite-fault inversion technique developed by Hartzell and Heaton (1983) is employed. A model fault plane with dimensions 30 km x 18 km is used to represent faulting during the earthquake. The model fault-plane is divided into 60 subfaults for spatial distribution of slip to be found in the inversion. Initial trials have revealed that a hypocentral depth of 10 km, a rupture velocity of 2,7 km/s, a fixed rake angle of -178o and unilateral rupture toward SE explain the data best. Variable rake ange inversion trial with rake angle varying between -90o and -180o has indicated that the faulting almost pure right-lateral. Therefore, fixed rake angle is preferred in the modeling. The final slip model suggests that the rupture of the earthquake was controlled by a large asperity that is located 13 km southeast and 5 km up-dip of the hpocentre with peak displacement of 85 cm. The main rupture is unilaterally propagated to the SE and covers a fault area of 20 x15 km2 with slip shallower than 10 km. Nevertheless, there is also a slip area at depth of 15 km with peak slip amplitude of 25 cm. The rupture lasted 10 s and the main seismic moment release occurred in the time range of 3-8 s. A seismic moment of 4,1x1019 Ntm (Mw6,4) is estimated for the preferred slip model. Keywords: 1 May 2003 Bingöl earthquake, finite-fault inversion, spatial distribution, rake angle