Liquefaction Damage Prediction of Residential Land and Houses Using Geophysical Survey Results

Damages such as settlement and tilting of detached houses due to ground liquefaction have often been observed during recent earthquakes. Ground surveys are necessary to predict the damage due to ground liquefaction. In this study, we focused on the surface wave exploration and passive liner array, which are ones of the geophysical survey methods. The surface wave exploration can tell us the ground information over the wide range. The latter one can give the information from the ground surface down to the deep part. These survey techniques can give us the ground conditions more accurately, more extensively and more quickly than the conventional ones. First, we conducted these surveys in Christchurch, New Zealand damaged by the 2011 Christchurch earthquake. The risk of liquefaction was then evaluated based on surveyed results. The evaluation method using the F_L and P_L values was used for judging the liquefaction risk. As a result, it was confirmed that the observed damage distribution almost coincided with the high risk area calculated by the shear wave velocity structure.