1995年奄美大島近海地震の断層パラメターと津波の発生 Fault Parameters and Tsunami Generation of the 1995 Amami-Oshima-Kinkai Earthquake
We estimated the fault parameters of the 1995 Amami-Oshima-Kinkai Earthquake, which occurred along the Ryukyu trench with a normal fault mechanism. The earthquake generated larger tsunamis than expected from its magnitude (<I>M</I><SUB>JMA</SUB> 6.7), about 3 m on nearby Kikai-jima Island. Among six fault models we considered, the low angle fault dipping to the east (model LA) best explains the observed data such as the aftershock distribution and the horizontal coseismic movement of Amami-Oshima Island inferred from GPS measurements. The fault is 60 km long, 30 km wide, 10-20km deep and the average slip on the fault is 1 m. Tsunami numerical computations indicate that the tsunami amplitudes, particularly at far-field, are insensitive to the fault parameters, suggesting that the large tsunami was not due to unusual source process. Numerical computations also show that the bathymetry between the source and Kikai-jima Island is responsible to the large tsunamis observed on the island.
地學雜誌 106(4), 546-556, 1997-08-25
Tokyo Geographical Society