使用因子分析方法研究九江5.7级地震前的地震活动异常

Research on anomalous seismicity before Jiujiang Earth quake with M_S5.7 by using factor analysis method

使用2005年11月26日江西九江5.7级地震前震中附近地区的地震资料,选择反映地震活动时、空、强特征的地震频次N(ML≥3.0)、b值、η值、A(b)值、Mf值、Ac值、C值和D值参量进行因子分析。这些参量之间具有一定的相关性,各参量在不同时段的变化各有所异,预报效果并不理想。但是根据因子分析可以得到反映地震活动时、空、强特征的综合指标Wfa值,该指标在九江5.7级地震前出现明显的异常变化。表明综合指标Wfa值可以较好地反映地震活动的异常特征。文中还对与因子分析结果的有关问题进行了讨论。

Based on the earthquake data around the epicenter before the Jiujiang earthquake with MsS. 7 occurred on Nov. 26, 2005 in Jiangxi province, the factor analysis method is applied to select the seismicity parameters of earthquake frequency N（ML≥3.0）, b-value, revalue, A（b）-value, Mf-value, Ac-value, C-value and D-value that reflect seismicity characteristics of time, space and magnitude in this paper. There is a certain correlation among these parameters. The variation of these parameters is different, and the anomaly of many parameters is not obvious before Jiujiang earthquake. The synthetic parameter Wfavalue reflected the seismicity characteristics of time, space and magnitude shows obvious anomaly. It shows that the synthetic parameter Wfa-value can reflect anomaly characteristics of seismicity. The other problems of the factor analysis method and conclusion are discussed in this paper.