SEGJ Technical Conference

Chain array analysis and seismic interferometry analysis on microtremors observed with a double linear seismometer array in Inzai City, Chiba Prefecture(part2)

Abstract In order to estimate 2-Dimensional S-wave velocities deeper than those obtained by Manya et al. (2018), we applied CCA analysis and 2-Dimensional Linear Array Microtremor Survey method to observed microtremors records. In CCA analysis, we obtained almost the same phase velocities as those obtained by normal SPAC analysis. However, phase velocities in the lower frequency range could not be obtained. In SPAC analysis, we calculated the Rayleigh wave phase velocities from microtremor records with distances of 7m, 14m, 21m and 28m. Then, we converted the Rayleigh wave phase velocities to 2D S wave velocity structures. Near the center of the survey line, it was found that the S wave velocity was about 350 m/s at a depth of about 50 m. It was found that the S-wave velocity was about 230 m/s at a depth of about 60 m at the survey line distances of about -70 m, 40 m, and 136.5 m. As a result, deeper 2-Dimensional S-wave velocities were deeper obtained than those obtained by ordinary SPAC analysis.