5:15 PM - 6:30 PM
[MIS34-P78] Attenuation Structure around Kumamoto Region.
Keywords:attenuation structure, Q
The seismic attenuation implies inelasticity or scattering of the structure. In this study, we estimate the 3-D attenuation structure beneath the Japanese islands by tomographic method. And we show the Kumamoto Region.
Data and Method
Vertical amplitude data of the JMA Catalog from January 1994 to December 2014. The data is represented by the indices Qp and Qs, which are dependent on the frequencies of ground motion. We estimate each earthquake mechanism, and the effect of the radiation pattern is also applied. The study area of the inversion is whole Japanese island, a grid with interval of 0.25 degree in horizontal is applied to this region at depth of every 5km to 50 km, and then 10km to 100km.
The target area of the Kumamoto Earthquake region, is shallow, so the resolution of the checker board test is almost good. Most of earthquakes are occurred in the high-Q region. Between Kuju region to Yufu, the low-Q area is laid, and earthquakes don’t occur in this series of the earthquakes.
The earthquake catalog used in this study is produced by the Japan Meteorological Agency, in cooperation with the Ministry of Education, Culture, Sports, Science and Technology. The catalog is based on seismic data provided by the National Research Institute for Earth Science and Disaster Prevention, the Japan Meteorological Agency, Hokkaido University, Hirosaki University, Tohoku University, the University of Tokyo, Nagoya University, Kyoto University, Kochi University, Kyushu University, Kagoshima University, the National Institute of Advanced Industrial Science and Technology, the Geographical Survey Institute, Tokyo Metropolis, Shizuoka Prefecture, Hot Springs Research Institute of Kanagawa Prefecture.
S.Sekine (2005): Tomographic Inversion of Ground Motion Amplitudes for the 3-D Attenuation Structure beneath the Japanese Islands, Report of the National Research Institute for Earth Science and Disaster Prevention, 68, 137-174