A DISCUSSION OF THE SEISMO-TECTONIC AND THE CAUSE OF THE TANGSHAN EARTHQUAKE

According to the synthetical analysis of geological background,some characteris-tics of precursory anomaly,distribution of seismic fissures.focal mechanism, etc.it has been considered that Tangshan earthquake is the result of the combined effect of horizontal compressive-stress due to westward subduction of pacific-plate and the up-ward compressive-stress due to mantle uplift and magma-intrusion.It has led to the counter clockwise twist of Tangshan massif, which is confined by several faults.The Tangshan earthquake occurred under the control of deep and shallow geological tecto-ni cs, and activity of deep magma.In this paper a tectonicmagma-thermo-seismic model of Tangshan earthquake has been suggested.