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本文叙述了在中国,特别是在华北地区观测到的一些地震活动性图象。高震级(M≥7.5)地震具有特定的间隔距离。华北近年7级地震分布成条块。强震前的临震地震活动具有相似性。特定地区的地震具有明显的相关性,分析其特征,表明这种相关现象不是一种传播过程;不能用“相关地震间具有直接的断层联系”来解释;而可能是大范围地层同时受力的结果。观测到大震前总有中小地震为其作前奏,并且大小地震间遵循一定的比例关系。以上这些活动性图象,可用地层受力屈曲的机理给以解释。根据这种观点,可推算出一般地震的b值将取0.75,火山地震、水库地震以及某些震群的b值将取1.5,而沿断层分布的地震的b值将为0.5.这些数值与实际情况比较符合,因而本文叙述的现象与分析结果,可能具有普遍意义。
This paper describes some seismicity images observed in China, especially in North China. High-magnitude (M ≥ 7.5) earthquakes have a specific separation distance. In recent years, the magnitude 7 earthquake in North China is distributed as a block. Earthquakes before the strong earthquakes have similarities. Earthquakes in a particular area have obvious correlations and their characteristics are analyzed to show that this related phenomenon is not a propagation process; it can not be explained by “a direct fault association between related earthquakes”; it may be that a large area of strata is simultaneously stressed result. It is observed that there are always small and medium-sized earthquakes before its occurrence as prelude to earthquakes and the magnitude of earthquakes follows a certain proportion. These above-mentioned active images can be explained by the mechanism of formation buckling. From this point of view, it can be deduced that the b value of a general earthquake will be 0.75, the b value of a volcanic earthquake, a reservoir earthquake and some swarms will be 1.5, and the b value of an earthquake distributed along a fault will be 0.5. The actual situation is more consistent, so the phenomenon described in this article and the results of the analysis may have universal significance.