摘要
本文在地震的发生时间服从Poison过程,而地震震级服从GutenbergRichter关系的前提下,对不同定义的加卸载响应比Y值的随机分布进行了探讨。结果表明:当在计算窗口的地震发生的期望数目较大(>40)时,Y1~Y5值的分布基本稳定,出现高加卸载响应比的概率极低。然而当计算窗口的地震期望数目过小时,Y2~Y5值则变得不太稳定。也就是说,服从Poison过程的地震序列,在计算窗口的地震期望数目过小时,也可能产生Y值较高的结果。为了使利用加卸载响应比预测地震更加可靠,文中给出了Y1、Y3在Poison模型下的90%、95%和99%的置信区间,这对判别加卸载响应比异常是非常有用的。
The random distribution of the loading and unloading respo nse ratios (LURR) of different definitions ( Y 1~Y 5 ) has been discussed b y using of the assumption that the earthquakes occur according to Poisson process and their magnitudes ob ey the Gutenberg Richter law. The results show that: the Y 1~Y 5 are qu ite stable or concentrated when the occurrence rate in the calculation time wind ow are relatively large ( >40 ); but when this occurrence rate becomes quite small, Y 2~Y 5 become quite variable or unstable. That is to say, a high value of LURR can be produced not only from seismicity previous to a large eart hquake, but also from a random series of earthquakes which obeys a Poisson proce ss. To check the influence of random factors in the catalogue to the LURR, the r andom distribution of the LURR under Poisson models by simulation has been calcu lated. 90%,95% and 99% confidence bands of Y 1 and Y 3 are given in this pap er, which is helpful to quantify the random influence and to determine LURR prec ursory anomalies.
引文
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