关键词: 地震构造, 孕震模式, 壳内多震层

Abstract: The structural media,internal and external environments of intracrustal seismogenic layer are the important factors which constrain the generation and occurrence of earthquakes,especially strong ones in this layer. Till now,the main advances of studies on the earthquake generating environments of seismogenic layer are as follows: Seismogenic layer is located at the lower part of upper crust to mid crust with the assemblage of amphibolite facies (greenschist facies at upper part of this layer) metamorphic and granitic rocks. It is a medium layer with the relatively high seismic velocity,high density and high resistivity and its lower part corresponds to the transition zone of brittle ductile deformation and high shear stress zone. Intracrustal low velocity high conductivity layers exist below this zone or strong seismic sources. The stress field in this layer is characterized by regional variation and the cut off temperatures for intracrustal seismicity range 300℃～400℃. Seismic source faults are characterized by regional variation and may have different earthquake generating mechanisms for different region. To a certain extent,the strong body earthquake generating model may be useful for the efforts of earthquake prediction.

Key words: Earthquak structure, Earthquake-generating model, Intracrustal seismogenic layer