ESTIMATION OF DEEP UNDERGROUND STRUCTURE IN SENDAI AREA BASED ON MICROTREMOR OBSERVATIONS AND STRONG-MOTION PREDICTON

Abstract

Microtremor observatios have been performed in Sendai Area. The relation between depth to bedrock and peak period of H/V spectral ratio has been shown. Underground structures in Sendai Area have been estimated comparing theoretical H/V ratio corresponding to particle orbit of fundamental-mode Rayleigh waves with observed H/V spectral ratio. The validity of the estimated structure has been verified by observed ground motions in the Near-Source Earthquake on September 15, 1998. The maximum acceleration distribution for the Nagamachi-Rifu fault has also been predicted by using the estimated structure.