阿蘇カルデラ周辺の地震について東部外輪山地域の地震活動

Abstract

A seismic observation was carried out from the late of January to the beginning of March, 1970, in order to investigate the seismic activity in the eastern area of the Volcano Aso. In this periodtwo temporal stations were set at the eastern and the southeastern plateau of the Aso caldera. Inanalyses, the data obtained from the seismic stations of the Volcanological Laboratory of KyotoUniversity were also used. The results are as follows: (1) the seismic activity of the eastern plateauseems to be very low in contrast to that of the northwestern plateau, (2) the small earthquakes ofwhich focal depth is 120 km are detected and their foci distribute in the zone of deep earthquakesin Kyusyu District.