Abstract：The relationship between the tectonic environment of deep crust and earthquakes are investigated, and the seismogenesis of earthquakes are further discussed, using the Pwave tomography beneath the Three Gorges reservoir dam and adjacent regions and earthquakes occurred before the impoundment of the Three Gorges reservoir. The main results indicate: the earthquakes which took place in the Three Gorges area, are closely associated with the tectonic environment of deep crust, most of those events occurred in or around the velocity gradient belts, whose formation are influenced by various factors of deep tectonics, are mainly developed by the bordering on the highvelocity anomaly with low velocity anomaly. The aforementioned phenomenon shows that the velocity gradient belt, which is considered as one of the most active places where the deep plate motions exist, is similar to the characteristics of buried fault zones. The regional tectonic stress field, deformation, dilation and upwards perturbation field and tensile stress generated by the partially molten materials of upper mantle, and thermal stress, which jointly contribute to the Three Gorges area, then lead to the activities of the faulting zones and buried faults and possibly activate the new ruptures, finally trigger earthquakes.
Li Qiang ,Zhao Xu ,Cai Jin’an et al. STUDY ON TECTONIC ENVIRONMENT OF DEEP CRUSTAND SEISMOGENESIS OF EARTHQUAKES BENEATHMAIN THREE GORGES RESERVOIR AREA[J]. jgg, 2010, 30(5): 1-7.
