Seismic Investigations in Residential Area Liquefied by the Mid Niigata Prefecture Earthquake in 2004

A surface-wave method and a seismic refraction method were applied to residential area liquefied by The Mid Niigata Prefecture Earthquake in 2004 in order to evaluate the applicability of seismic investigations to a liquefaction potential evaluation. The result of the analysis agreed with actual liquefaction damage. A liquefaction potential analysis by shear-wave velocity obtained from the surface-wave method was carried out. Groundwater level estimated by the seismic refraction method also agreed with that of monitoring wells. The shear-wave velocity and the groundwater level are important factors in the liquefaction potential evaluation. The result implies that the seismic investigations enable us to evaluate the liquefaction potential from the surface nondestructively.