2018 Volume 18 Issue 4 Pages 4_38-4_54
In the ‘Recipe’ for predicting strong ground motions from crustal earthquakes proposed by the Headquarters for Earthquake Research Promotion, Japan (2016), the seismic moment is evaluated from the seismic fault area, excluding the fault area located in the surface layer, even when the fault rupture reaches the surface, and this leads to the underestimation of the seismic moment. Hence, in this paper, we examined the effects of two different ways of counting fault areas, that are the seismic fault area and the entire ruptured fault area, on the evaluated fault parameters. Then, we presented three fault models with the fault length of 30 km, 50 km, and 200 km, and we predicted strong ground motions by the stochastic Green's function method. We found that the effects of the different ways of counting fault areas on the strong ground motions from the faults 30 km and 50 km long were small for peak ground accelerations and comparatively large for peak ground velocities and response spectra in the longer period range. On the other hand, the effects on the strong ground motions from the fault 200 km long were little for peak ground accelerations and peak ground velocities while the effects were a little for response spectra in the period longer than 3 seconds.
