Investigation of Microearthquakes in Kinki District -Seismicity and mechanism of their occurrence-

Abstract

Observation of microearthquakes in the western part of Kinki District has been carried out at 5 stations attached to the Tottori Microearthquake Observatory. Epicenters of about 200 earthquakes for ten months since Angust, 1964 were determined, giving a particular pattern of distribution. The areas in which the earthquakes occur frequently are separated in a complicated but nevertheless sharp manner from the areas where earthquakes seldom occur. Magnitude of these earthquakes was distributed from -1 up to more than 4. The distribution of direction of the first P motion shows a definite pattern for almost all earthquakes. This pattern coincides well with that of earthquakes with larger magnitude in this district.