Source Model Of 1999 November 12 Duzce, Turkey Earthquake Using Empirical Green's Function Method

On 12 November 1999, an earthquake of moment magnitude 7.1, Io=X (MSK) occurred on Duzce Fault, in the eastern part of the Marmara Region just 3 months after Kocaeli (Mw:7.4) Earthquake. The strong motion networks deployed by several national and international institutes supplied us remarkable data to form the source model of this particular event. We examined the source model of Duzce event using 3 strong motion data, taken place in eastern and western side of the fault rupture within the radius of 65 km. We performed the simulation by the method of Irikura (1986) which essentially uses the small events as empirical Green's function and sums them up to follow the omega-squared scaling law. The best source model was decided by fitting synthetic acceleration, velocity and displacement traces to observed waveforms. Since there is no information about the mechanism of the element event used as green's function, for initial model, it is assumed that the source mechanism of the main and element events are the same. Even though the length of rupture area was calculated as approximately 20km by 40 km based on surface rupture observation as well as aftershock distribution, the strong motion generation area might be relatively smaller compared to the previous estimations. The size of the asperity was calculated as about 8km by 13km. The rupture started at the western bottom of the asperity and propagated radially from the hypocenter. Regarding the S-P time calculation of the Bolu (BLU) Station data, the possibility of existence of super shear velocity in eastern side of the fault were suggested by Bouchon et.al. (2001). We also take into consideration of this phenomenon during the simulation.