SEGJ Technical Conference

Estimation of subsurface velocity structures and earthquake ground motions along the closed Takachiho railway

Abstract We observed earthquake ground motions at two embankment sites and an excavation site in the closed Takachiro railway. To estimate S-wave velocity structures along the railway, we performed array microtremor observations at two sites and single-station of microtremor observations at thirty sites along about 600m railway section. At first, we estimated the S-wave velocity structures at two embankment sites installed seismographs. Secondary, we estimated the S-wave velocity structures one by one along the railway based on the H/V spectral ratio, referring to the velocity structures at the seismic stations. Finally, we evaluated earthquake ground motions along the railway using the estimated S-wave velocity structures. As the results, we confirmed that the estimations were in good agreement with the observations.