経験的グリーン関数法による1993年釧路沖地震の強震動波形の合成

Abstract

We made the simulation of strong ground motions from the Jan. 15, 1993 Kushiro-Oki earthquake (MJMA = 7.8) using the empirical Green's function method.We adopted the largest aftershock (Feb. 4, 1993, MJMA=4.9) as an empirical Green's function event. Synthetic waveforms were calculated using the formulas which take into consideration the difference of the average stress drop between the large and small events.We compared the envelopes of the observed and synthetic waveforms for the 2-10Hz bandpass-filtered acceleration seismograms and estimated the size of the area generating high frequency waves by forward modeling. High frequency waves between 2 and 10Hz were estimated to have been radiated from the area of 34km × 49km.