【摘要】 讨论了1965年以来云南地区强震孕育过程中地震类型的动态变化,发现:云南地区发生6.7级以上强震前数月至数年,云南省内均有2次以上5级双震或群震型地震发生;部分强震前数月至数年,至少有3次以上前主震型地震密集发生.强震发生在这些前主震、双震、群震型地震150 km以外地区.典型地区地震类型的追踪研究也表明:宁蒗地区发生5级双震、前主震型地震以及腾冲地区发生6级群震型地震,云南地区均发生6.5级和7级以上强震,但地点远在宁蒗、腾冲200 km以外地区.实验中,随着载荷的增大,岩样的破裂类型经历了主余破、孤立破→群破→前主破→破裂类型多元化的过程.震例和实验研究结果的对照显示:地震的类型不仅与发震地区地质构造有关,也与地壳介质所处的应力状态有关.更多还原

【Abstract】 The dynamic changes of earthquake types during strong earthquake preparation processes since 1965 in Yunnan were discussed.It was found that more than two M5.0 double earthquakes or swarm earthquakes occurred several months or years before M≥6.0 strong earthquakes.Part of strong earthquakes at least three preceding main shocks densely happened several months or years ago.All strong earthquakes occurred 150?km outside the areas where the preceding main shocks,double or swarm earthquakes located.The trace studies of earthquake kinds ever the typical areas indicated that M6.5 and M≥7 earthquakes always happened after M5.0 double and preceding main earthquakes occurred in Ninglang area and M6.0 swarm earthquakes occurred in Tengchong area.How ever the earthquakes located at areas which were more than 200?km far from the Ninglang and Tengchong areas.In rock rupture-type experiment,the rock samples experienced poly-rupture process orderly including the main and after crack,lone crack,swarm crack and preceding crack with load increasing.The experimental results and earthquake examples suggested that the seismic styles were relantive to both the geological structure in the seismic region and the stress conditions of in crust materials.更多还原