甲楽城断層周辺での地震活動と地震波伝播特性

Abstract

Kaburaki Fault System is one of the biggest active faults in Fukui Prefecture. It showsclear vertical displacement along the Echizen coastal line. We set a temporary station forearthquake observation just on the Kaburaki fault. More than on hundred and fifty earth-quakes were observed for about one and half years.Some microearthquakes which could not be detected by the Hokuriku MicroearthquakeObservatory, Kyoto University, were considered to occur near SUJ station. But, the seismicactivity there is not so high.The dominant frequencies of the observed wave-forms differ azimuthally. The wave-forms of earthquakes which occur in southern area from our observation station are relativelylower than those of northern ones. The difference of dominant frequencies is supposed to becaused by the existence of the low Q mass just south of SUJ.