ABSTRACT

The Izu Peninsula is a resort area located about one hundred kilometers southwest of Tokyo, Japan. In the last twenty years, a number of earthquake swarms have occurred in succession off the east coast of the Izu Peninsula. Since these earthquakes occurred under the sea, this seismic area was affected by cyclic tidal loading. Although there are many reports about the relation between seismic activity and the oceanic tide, the relation is not clear in many cases. However, I found a noticeable example of the tidal effect in the case of the 1980 earthquake swarm off the east coast of the Izu Peninsula.