抄録
Subsurface geological structure of the Fukui basin where the 1948 Fukui Earthquake (M7.1) occurred has been studied by P and S wave seismic reflection survey together with a trench excavation survey at the eastern edge of the basin. In the central part of the basin, no distinctive fault has been detected by the P wave seismic reflection survey. Also, at the eastern edge of the basin, no evidence of faulting associated with the 1948 event has been detected by S wave seismic reflection and trench excavation surveys. However, liquefaction of gravel layer has been revealed in a trench at the eastern edge of the basin and its date is estimated sometime between A. D. 1200. and A. D. 1400. These results suggest that the faulting of the 1948 Fukui Earthquake (M7.1) is dominant with strike slip component, and hence it is concluded that no earthquake fault appeared on the ground surface other than the intensive surface cracks reported as the evidence of earthquake fault.
