关键词: 等震线, 震源参数, 应力降, 断层错距, 断层错动角

Abstract: The relationship between geometrical factors of seismic intensity distribution and hypocentral parameters of strike-slip earthquake is considered by means of a simplified elliptic model of hypocentre in which the effects of environmental stiffness of hypocentral region and nonuniform resistance along fault zone are taken into account, and a new method, so-called isoseisms method, is developed preliminarily for estimating stress drop and slip displacement of historical earthquake. Also, the relationship between axes ratio of hypocentral ellipse and orientation of maximum principal stress relative to fault zone is presented in this paper. The method has been examined by estimating the hypocentral parameters of Tangshan(1976), Tonghai (1970), Luhuo(1973) and Yongshan (1974) earthquakes and comparing them with those estimated by the traditional methods.

Key words: Isoseisms, Hypocentral parameter, Stress drop, Slip displacement Sliding angle