SHALLOW SUBSURFACE MODEL AT FURUKAWA DISTRICT BASED ON VERY DENSE SEISMIC ARRAY OBSERVATIONS

Abstract

 During 2011 Tohoku-oki earthquake, strong ground motion caused serious damage to residences at Furukawa area in Miyagi Prefecture, north eastern part of Japan. Based on the damage distribution, severe damages were concentrated in southern part of Furukawa district. The variation of damage distribution implies that the ground motion characteristics were not uniform in Furukawa district. In this study, we started to install the very dense seismic-array and observe ground motion. We assumed one-dimentional horizontally-layered structure just under the staions and estimated ground structure by using the records based on the observation. Then, we calculated velocity waveforms of the earthquake on January 1^st 2012, by using the model. However, the waveforms do not agree well for the following phases, and this implies that one-dimentional horizontally-layered structure is not enough assumption to simulate the ground motion in Furukawa district.