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地震话动空间图象随时间的变化可能是强震发生的前兆信息。强震发生前,由于震源应力场主导作用的逐渐加强,它对周围地区地震话动的控制作用也日益明显。本文从韦布尔分布出发,求得表征地震间相互作用的参数,并分别求得华北地震区内的历史地震及现代中小地震话动的v值随时间的变化。结果表明,华北地震区的中强地震话动的300年左右周期与由v值得到的结果相一致;邢台地震前,v值呈现下降-上升的变化过程,表示地震活动的密集-平静过程,对不同震级下限的v值的计算结果表明,地震的随机性随着震级下限的增大而减弱,强震前地震话动的异常特征在一定震级水平的地震活动中才能显示出来。
The temporal variation of the spatial image of the earthquake may be a precursor of strong earthquakes. Prior to the strong earthquakes, because of the gradual strengthening of the dominant role of the source stress field, the controlling role of the earthquake on the surrounding areas became increasingly evident. Based on the Weibull distribution, we obtained the parameters that characterize the interaction between the earthquakes and obtained the changes over time of the v values of the historical earthquakes in North China and those of the modern small and medium earthquakes respectively. The results show that the period of about 300 years of moderate-strong earthquakes in North China earthquake area is consistent with the result obtained from the v-value. Before the Xingtai earthquake, the v-value shows a decreasing-rising process, indicating the intensive seismic activity, The results of calculating the v value of the lower limit of different magnitude show that the randomness of the earthquake weakens with the increase of the lower limit of the magnitude, and the anomalous features of the earthquake before the strong earthquake can be displayed in the earthquake activity of a certain magnitude level.