水的渗透作用及新丰江水库地震的特点和机制

据具有孔隙的岩石中水的渗透作用及Mogi的地震分类原则,提出水的渗透过程形成了库区有效应力分布的非稳定的不均匀状态,水库地震的序列特点与其密切相关;讨论了水的渗透对引起主震的作用,得出水库区的渗透率约为10~(-4)达西,认为在蓄水前库区的构造应力场未达到临界状态,库水与地下水形成新水系,后在此基础上进一步渗透,孔隙压力增加,构造应力进一步集中,激发主震;根据库仑准则讨论了应力场的转换,提出主震后应力场的转换是造成前震和余震的震源应力场方向不同的原因

THE EFFECT OF INFILTRATING OF WATER AND MECHANISM AND CHARACTERISTICS OF EARTHQUAKES IN XINFENGJIANG RESERVOIR

According to the effect of water infiltrating in porous rocks and the generalized classification of earthquake by Bell and Nur and Mogi, it is suggested that the process of infiltrating of water may be responsible for the unstable and inhomogeneous distribu-tioneh of the effective stress over the reservoir area. The characteristics of the earthquake sequence in the reservoir are related to this kind of stress distribution. The effect of infiltrating water on the main shock is discussed. The permeability can be found to be 10-4 darcy. It is suggested that the tectonic stress in the reservoir area is not in the critical state; water in the reservoir area collected along with underground water to form a new water system; and then water widely infiltrated into deeper parts with the pore pressure increasing and the tectonic stress concentrating to cause the main shock. On the basis of the Coulomb criterion, the transformation of the stress field is studied. The transformation of the stress field after the main shock may account for different stress state of earthquake sources between the foreshock and the aftershock