Features starting earthquakes in the areas of subduction

Abstract

Subduction is the phenomenon of movement of one lithospheric plate under another, arising in connection with the heterogeneity of both geometrical and physical parameters of the lithospheric plates approaching each other. Such phenomena can occur in land, ocean and coastal areas. Active boundaries of the plates are divided into two types – subduction and collision ones. Collision processes are peculiar to the interaction of continental lithospheric plates and lead mainly to the twisting and generation of new mountains, while the subduction ones tend to cause earthquakes. By subduction, a part of the ocean floor sinks beneath the land plate. At great depth this part melts and due to the spreading it spreads and forms new crust both under the land and under the ocean. Subduction zones were discovered and described by the seismologist Benioff. Earthquakes occur most frequently in these zones. Benioff called them seismic focal zones, now they are called Benioff zones. There are attempts to explain the reasons for such properties of the Benioff zones, but they are not based on rigorous mechanical and mathematical approaches and are not convincing. The starting earthquakes are studied in the sone of subduction.