SEGJ Technical Conference

Subsurface condition at the station IWTH25 of KiK-net

Abstract The 2008 Iwate-Miyagi Nairiku earthquake produced relatively high-frequency ground motions, which resulted in the 4g acceleration at the KiK-net IWTH25 station. We conducted a seismic refraction survey, surface wave survey, and resistivity survey at the site around the station IWTH25 to understand the mechanism of the strong high-frequency ground motion. The result shows the velocity at the shallow subsurface layer is slower than PS logging data, Vp=400-500m/s, Vs=150-200m/s, and the depth of the layer can be estimated as 1-3m.