Seismological Research On The Structure Of Japan's Subduction Region

In the subduction zone,the crust of the earth is subducted into the deep mantle,which brings the crust material into the mantle and forms a downward flow in the mantle convection.This process is the key to the material circulation of the earth.Research on the structure of the subduction area can help us understand the mantle convection pattern and the process of Earth formation.The development of the subduction zone was accompanied by strong earthquakes and volcanic activity.Many subduction seismic belts and island arc volcanoes were formed,resulting in a large number of geological disasters.Therefore,study on subducting would help to understand the causes of earthquakes and the source of volcanic material and other geophysical phenomenon.The geological disasters caused by numerous earthquakes in the subduction region,but also provide us large amount of data to support the study on subducting structure.Based on the theoretical numerical simulation of the interface of the subduction zone in Japan,this paper reconstructs the reflection data from the interface between the Moho and the subduction zone.It is proved theoretically that the seismic interferometry can effectively detect the subduction zone structure.The author used the ScS multiple wave method to study the undulating structure of 410 km and 660 km discontinuities in the mantle transition zone caused by the subduction in Japan,and obtained the discontinuities structure of Japanese Sea,southern Okhotsk Sea,and the Philippine Sea by using Japanese Fnet data.The results of the study show that there are distinct uplifts and subsidences in 660-km discontinuous interfaces in different regions,and the interfacial undulations in the 410-km section are more complex.