Shallow subsurface structure estimated from dense aftershock records and microtremor observations in Furukawa district, Miyagi, Japan

摘要: We conducted single-site and array observations of microtremors in order to revise the shallow subsurface structure Furukawa district, Miyagi, Japan, where severe residential damage was reported during Great Eastern Japan Earthquake 2011, off Pacific coast Tohoku. The phase velocities Rayleigh waves are estimated from at three sites, S-wave velocity models established. spatial distribution predominant periods is for surface layer, on basis spectral ratio horizontal vertical components (H/V) obtained observations. then compared ground motion records a dense seismometer network with results microtremor observations, revised model (~100 m) district. implies that slower near-surface deeper basement be found southern eastern areas. It structures concentrated an area average value transfer functions frequency range 2 4 Hz large.