[S07-2] Hazard and risk assessment I

[S07-2-04] Seismic Hazard Assessment of the 1995 Kobe Earthquake: Before and After

^○Hiroe Miyake (The University of Tokyo, Tokyo, Japan)

The 1995 Kobe earthquake was a turning point for the seismic hazard assessment in Japan. Since then, the Headquarter of Earthquake Research Promotion has been established at the government. Crustal and subduction earthquake potentials are evaluated, and the national seismic hazard map was released in 2005. The ground motion prediction technique for broadband time histories is validated for recent crustal earthquakes (e.g., 2000 Tottori and 2005 Fukuoka) and past subduction earthquakes (e.g, 1944 Tonankai, 1946 Nankai, 1968 Hyuga-nada, 1978 Miyagi-oki, and 2003 Tokachi-oki). However, there are no validation of crustal earthquakes before the 1995 Kobe earthquake. From this motivation, we estimate ground motions for the 1995 Kobe earthquake using the prediction technique and information before and after the earthquake. The first approach is based on the ground motion prediction equation (GMPE). Fukushima and Tanaka (1990) is used as the pre-Kobe GMPE with site amplification factors released before 1995. As for the post-Kobe GMPE, Si and Midorikawa (1999) is used with latest site amplification factors. The comparison is performed at each mesh following the procedure of Ishikawa et al. (2011). The second approach is based on the empirical Green's function method with source modeling. We compare a homogeneous source model that follows the scaling laws of Matsuda (1975) and Takemura (1998) as the pre-Kobe source model, and a characterized source model from Kamae and Irikura (1998) and the recipe of Irikura and Miyake (2001, 2011) as the post-Kobe source model. In addition to the above fault models, various source models are recently proposed by kinematic, pseudo-dynamic, and dynamic approaches. Since the comparison technique is valid for these approaches at each period, it is useful to judge ground motion pulses that enhance response spectra.