Strong ground motion simulation based on the empirical Green's function method
Speaker: Shih-Wei Yang
Abstract
The empirical Green's function method proposed by Irikura(1986) is one of the most powerful methods for predicting strong ground motions from large earthquakes. This method is based on a scaling law of fault parameters for large and small events (Kanamori and Anderson, 1975) and the omega-squared source spectra(Aki, 1967). The waveform for a large event is synthesized by summing the records of small events with corrections for the difference in the slip velocity time function. In Irikura's study(1986), the scaling parameters needed for this technique, N(interger value) and C, can be derived from the constant levels of the displacement and acceleration amplitude spectra of the large and small events. This method does not require knowledge of the explicit shape of the slip velocity time function for the small event. Kamae and Kawabe(2004) provided a preliminary source model for the 2003 Tokachi-oki earthquake estimated by the empirical Green's function method (Irikura, 1986). They assumed that ground motions are generated from several asperities, each of which has a uniform stress drop with a finite extent on the mainshock fault plane and obeys an ω^( -2) spectral sacling. Finally, they determined the source parameters for three asperities located on the fault plane from the comparisons between the synthesized broad-band strong ground motion and the observed ones.
Reference
Irikura, K. Prediction of strong ground motion using empirical Green's function. Proc. 7 th Japan Earthq.Eng. Symp.,151-156, 1986.
Kamae, K. and H. Kawabe. Source model composed of asperities for the 2003 Tokachi-oki, Japan, earthquake (M JMA =8.0) estimated by the empirical Green's function method. Earth Planets Space , 56 , 323-327,2004.