Subsurface Geology and Active Faults under the Sedimentary Basin in Kobe City and Its Surrounding Area

摘要

Seismic reflection surveys and deep drilling have been carried out for the clarification of subsurface geology and concealed faults under the Kobe-Hanshin area by Hyogo Prefecture, Kobe City, and the Geological Survey of Japan, since the 1995 Hyogoken-Nanbu earthquake. As a result, it has become clear that the Kobe-Hanshin alluvial plain is underlain by Pliocene-Pleistocene sediments, which consists of mainly Osaka Group members, range from hundreds to 1,500 meters in thickness and con- ceal active faults a short distance from well- known active faults such as Suwayama fault and Gosukebashi fault.