東海地域の長期的スロースリップイベントおよび地震サイクルの再現の試み

Abstract

Long-term slow slip events with the recurrence period of about 10-30 years have been observed beneath Lake Hamana in the Tokai district where historically great interplate earthquakes occurred repeatedly. We intend to simulate the recurrent slow slip events before the occurrence of cyclic great earthquakes using a three-dimensional earthquake cycle model based on the rate- and state-dependent friction law with heterogeneous friction parameters on the plate interface. In our model we can simulate recurring slow slip events with the period of about 30-40 years near beneath Lake Hamana, by applying small negative values to frictional parameter (a-b)and small values to characteristic distance L for the western region of the Tokai district, and large values to L for the regions off Tokai district where seismic structure surveys reveal the existence of a subducting ridge.