SEGJ Technical Conference

Validation of S-wave velocity structure model around Fujikawa-kako fault zone using array microtremor exploration and seismic interferometry

Abstract In order to upgrade the subsurface structure model for strong motion prediction around the Fujikawa-kako fault zone, we perform array microtremor exploration and we also apply seismic interferometry to the microtremor record continuously observed at the temporary ground motion station network to validate the S-wave velocity structure model. The vertical array microtremor record was used for SPAC analysis to estimate phase velocity dispersion curve of Rayleigh-wave. The crosscorrelation function between the station pair was calculated using several months of records observed at the temporary stations. Multiple filter analysis was used to observe group velocity dispersion curve of Rayleigh- and Love-wave. We performed tomographic analysis to obtain the spatial distribution of group velocity around the fault zone. We then compared the dispersion curve estimated from the tomography with theoretical curve that can be calculated from the subsurface structure model at each cell.