Microearthquake Activity in Central Honshu, Japan (Part 1): Seismicity of Microearthquakes in the Vicinity of the Neo Valley Fault@@@根尾谷断層周辺の微小地震活動

In order to study the seismic activity of microearthquakes in the southern part of the Neo Valley fault, an observation was carried out in 1968 from September 27 to November 2. Seven observing stations were set near the four stations of Inuyama Seismological Observatory.About 400 microearthquakes were recorded during this observation, but about 50 epicenters could be determined. Their magnitudes were less than 2.Microearthquakes occurred most frequently in the southwestern side of the fault, especially in the area upheaved by the Nobi earthquake of 1891. On the contrary, very few earthquakes occurred in the northeastern side. The focal depths of these shocks were very shallow.