2002 Volume 54 Issue 4 Pages 557-573
In order to evaluate the fault activity associated with the 2000 Tottori-ken Seibu earthquake, we carried out aerial photograph interpretations of fault landforms, geological investigation and trenching study in the epicentral area.
As the results of the aerial photograph interpretation, we found some northwest-southeast trending lineaments with sinistral offsets of valleys and ridges in the epicentral area. Above lineaments are sub-parallel and the total length of the lineaments is about 23km. The fracture zones with fault gouge and horizontal striations on sharp fault planes were found along the lineaments, the fact also suggests that the lineaments coincide with the active faults. According to the outcrop exposure of the fault and trench excavation at Kusumi, we found the evidence of the recent surface-ruptured event that had occurred sometime between 770-1, 260 A.D. Hence there is possibility to estimate the magnitude 7 class earthquake before the 2000 Tottori-ken Seibu earthquake by the lineament length of about 23km.
