鳥取一島根県境付近の地震活動

Abstract

Since the occurrence of 27 October, 1989 earthquake (M 5.3), the seismic activity on the border of Tottori-Shimane prefecture have become remarkably high.On the west side of Tottori prefecture, five earthquakes (M ・.1) occurred along a line from southeast to northwest direction.This line with a length about 10 km may be an earthquake fault system in this area.To obtain the accurate earthquake foci, portable seismic observation systems were temporally settled at six stations on the border of two prefectures.We found that the lower limit of earthquake distribution were about 12km depth.The conspicuous "X" phases were found between P and S arrive on the seismogram for three stations. This phase may be a reflected wave from a liquid layer.