GIS Analysis of Earthquake Damage Ratio Based on the Distance from Active Faults: Building and Buried Pipe Damage in Nishinomiya City in the Hyogoken-Nanbu Earthquake

There are three reasons for the generation for a seismic disaster zone by the Hyogoken-Nanbu earthquake: (1) the focusing effect of strong earthquake motion based on underground irregular structural models; (2) the edge effect of strong ground motion by three-dimensional deep irregular geological structures; (3) the directivity effect of strong ground motion based on moving active faults underground. The directivity effect means the distribution of peak ground velocities along a line perpendicular to the structure for the finite moving sources. In this study we analyzed the damage ratios for buildings and buried pipes in Nishinomiya city based on distance from the estimated active fault lines moving underground using GIS categories. The building damage ratio is very high level in a narrow zone about 2km from active fault lines as measured by the directivity effect.