Seismicity, subduction zone

Abstract

Recent investigations have significantly developed our understanding of generation mechanism for earthquakes in subduction zones. Asperity model seems to be applicable to interplate earthquakes. This gives us a theoretical background for long-term earthquake forecast: Place and magnitude of future earthquakes can be estimated from information on locations and sizes of asperities on the plate boundary. Dehydration embrittlement model seems to work as the generation mechanism for intraslab intermediate-depth earthquakes, particularly for earthquakes in the slab crust. Aqueous fluids expelled by the dehydration reaction in the subducted plate migrate upward, finally reaching the arc crust. Recent investigations have shown that the fluids thus supplied originally from the subducting plate play an important role in generating shallow inland intraplate earthquakes. Generation mechanism for deep earthquakes is still an open question. More systematic and intensified studies are expected to resolve it.