Estimation of vibration characteristics of Kuzuryu River bank and subsurface structures based on microtremor observations

Abstract

The Fukui Earthquake wreaked havoc on the Kuzuryu River levee. In this study, we carried out microtremor observations densely on the Kuzuryu River bank. An extended SPAC analysis was applied to the collected array observation data to estimate Rayleigh wave phase velocities. Transfer functions between the top and toe of the dike and H/V spectra of the levee crowns were calculated to determine the predominant periods of the embankment-ground systems. S-wave velocity structures were back-analyzed based on the H/V spectra. It was confirmed that the earthquake damages on the embankment were harmonized with the back-analyzed structures.