摘要
从已诱发地震的水库来寻求水库诱发地震的机理是现实的。据此,本文分析了目前国内外已有的近百个水库震例,结果发现:a、水库诱发地震的最大震级M:与坝高H(或库水位)并未有明显的正相关性,单纯的荷载观是片面的;b、诱发地震区与库水荷载,尤其是与可渗透的断层应力型式,如正断层型或走滑型及二者的复合型式有关;c、水库诱震震源的深度及强度在某种程度上取决于不同工程地质岩组的性质;d、重力变形破坏现象发育,形成强烈对比性地貌的岸陡谷深的狭长库段,诱震库段的长宽比一般大于10:1;e。
It is natural to explore the mechanism of reservoirinduced earthquake from known earthquake—inducing reservoirs. For this reason, the author has analysed nearly one hundred cases of reservoir—induced earthquakes reported at home and abroad. The results show that: a)There is no abvious plus corretation between maximum magnitude(Ms)and dam height(H) or water level. The exclusive concern about loading theory is wrong. b) Induced earthquakes have something to do with the loading of a reservoir, especially with such permeable fault stress trpes as normal faults or slipping faults and their composite type. c)The depth of focus ofa reservoirinduced earthquake and the strength depand to come degree on the nature of lithological suits of engineering geology. d)Induced earthquakes may occur in a long and narrow sector on the banks of a reservoir. In the sector steep banks with deep vallays are usually well developed because of gravitational deformation. The ratio of length/width of a sector is more than 10. e)Reservoir—induced earthquakes are characterized by higher b values. The relationship of b and ( stands for a mean magnityde in a certain period)in foreshocks, mainshocks or aftershocks is different and being different from that of a natural earthquake in the same area. Thus, the concept of inducement degree is introduced. f)An active fault in an induced earthquake area has a special permeating effect. Finally the paper has discussed the relationship between magnitude and impounding time, compared the relationship of magnitudes and intensities of reservoir—induced earthquakes in China with that of Chinese shallow earthquakes, and concluded that the energy of reservoir—induced earthquakes is finite, only having a trifling effect on a strongly active earthquake zone or a region with high stress field.
