Abstract:Based on the crust structure in China and its vicinity areas, especially background of deep crust structure where some large earthquakes took place in recent years, this paper discusses the possible structure model for the occurrence of earthquakes.
The results show that all modern seismicity occurred in the places where the thickness of crust changed rapidly or the structure twisted; Moreover, in these areas shocks would exist on the slopes or fringes of lifting parts of top upper mantle and other lifting areas nearly. In these spots the stress easily accumulates and breaks take place frequently.
This is the deep structure background of occurrence of earthquakes Furthermore, the areas where deep earthquakes take place are closely related to the high gradient variation of gravity field, magnetic field, and to low resistance layers, low and high velocity layers.
This kind of relation between earthquakes and deep geological structure as well as features of geophysical fields must be envisaged in the earthquakes prediction and in searching for their origin.
