Microearthquake Activity in Central Honshu, Japan (Part 2).

In the first paper under the same title, the seismic activity of microearthquakes in the vicinity of the Neo Valley fault was studied and the seismicity of this region was elucidated. However, in the region to the sourth of Inuyama seismological observatory few information had been obtained. In order to study the seismicity of this region, the observation of microearthquakes in Mikawa district was carried out in 1969 for 75 days from June 25 to August 31. Four temporary observation stations which were installed in this region, and all the stations of Inuyama seismological observatory were used in this study, During this observation, about 600 earthquakes were recorded and about 120 hypocenters could be determined. The magnitudes of these earthquakes were less than 2.One of the results deduced from this observation was that microearthquakes occurred frequently at depths between 30km and 35km, and shallow earthquakes were very few in this region.