关键词: 应力, 损伤, 耦合效应, 重力变化

Abstract: Early in the 60s-70s of the 20th century, Japanese and American scientists have successfully observed the variation of gravity associated with earthquake process. In China, many researchers have studied the gravity field of some typical earthquakes. The results showed that observable variations of gravity do exist during the development process of medium-strong earthquakes, and that different earthquakes have different features of gravity variation. It is considered that the density variation in the crust may be an important factor. In this paper a model of stress-failure coupling effect is proposed in the light of failure mechanism. In addition, the theoretical relation between the stress failure coupling effect and variation of gravity in the crust is derived according to strain equivalent hypothesis. Furthermore, the different features of gravity evolution during the development processes of the Tangshan earthquake (M_S7.8) in 1976 and the Kunlun earthquake (M_S8.1) in 2001 are simulated through rock mechanical test with various loading paths. The results are something in good agreement with the actual facts and show that the stress failure coupling effect may be a physical explanation of gravity change before earthquake.

Key words: stress-failure, coupling effect, gravity variation