Earth Planets Space, Vol. 58 (No. 1), pp. 99-104, 2006LETTER
Wataru Suzuki and Tomotaka Iwata
Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
(Received August 9, 2005; Revised November 17, 2005; Accepted November 21, 2005; Online published January 27, 2006)
We estimated strong motion generation area (SMGA) source model which is responsible for broadband (0.2, 0.3-10 Hz) strong motions of the 2005 west off Fukuoka prefecture earthquake and its largest aftershock using the empirical Green's function (EGF) method. The estimated SMGAs are almost corresponding to the large slip area deduced by kinematic waveform inversion. The SMGA rupture for the mainshock propagated mainly upward and toward the northwest with rupture velocity of 3.15 km/s. The size of the SMGA follows the self-similar empirical formula of the asperity size derived by Somerville et al. (1999). The stress drop of the mainshock SMGA is calculated to be 10.7 MPa, which is larger than those of the largest aftershock SMGA and the aftershocks used as EGF.
Key words: Empirical Green's function method, broadband strong motion, source model, stress drop.