基于区域-时间-长度算法的区域地震活动与强震关系研究

Relationship between regional seismic activity and strong earthquake based on the region-time-length algorithm

基于区域-时间-长度(RTL)算法,本文以汶川M_S8.0、于田M_S7.3、芦山M_S7.0、鲁甸M_S6.5及景谷M_S6.6地震为例,对强震前地震活动异常空间分布与发震地点的关系进行分析,并根据新提出的物理参数区域-时间-长度的面积分I_(RTL)探索区域地震活动水平与地震发生时间的关系.结果显示:3次M_S≥7.0强震前均检测到地震活动平静,2次M_S>6.0地震前均检测到地震活动增强,这些地震活动平静和增强异常主要分布在震中及其附近潜在发震断裂带及周边,异常范围和异常程度随时间由小到大再到小.M_S≥7.0强震前,地震活动平静主体区的I_(RTL)曲线在震前1—3年从零值下降至低谷后回升,低谷点与地震发生的时间间隔为9—18个月;鲁甸M_S6.5和景谷M_S6.6地震前,I_(RTL)曲线分别在震前1年和1.8年由低值开始上升,达到峰值后回落,峰值点与地震发生的时间间隔分别为3个月和9个月.本文结果表明,地震活动平静的I_(RTL)低谷点和地震活动增强的I_(RTL)峰值点对地震发生可能有一定的指示意义.

Taking Wenchuan Ms8.0, Yutian Ms7.3, Lushan Ms7.0, Ludian Ms6.5 and Jinggu Ms6.6 earthquakes as examples, the relationship between spatial anomaly distribution of seismic activities and earthquakes occurrence location was analyzed based on the region-time-length （RTL） algorithm. And the relationship between regional seismic activity and earthquake occurrence time based on the new physical parameter IRTL which was the surface integral in respect to region-time-length was explored. The results show that seismic quie- scence was detected prior to the three strong earthquakes with Ms≥7. 0, and an enhancement of seismic activity was detected before the two Ms〉6. 0 eartn- quakes. Spatial anomalies of the above seismic quiescence and enhancement were mainly distributed in the potential causative fault and its surrounding areas near the epicenters. The range and degree of anomalies chronologically changed from small to large, and then to small again. During 1-3 years prior to the earthquakes with Ms≥7, O, IRTL decreased from the zero value; and when fall- ing to the lowest value, it rebounded. The time length from the lowest point of Ip, TL curve to the earthquake occurrence was 9-18 months. Before the Ludian Ms6.5 and Jinggu Ms6. 6 earthquakes, IRTI. curve began to increase from the lowest point 1 year and 1.8 years separately, and then reduced after reaching the peak point. The time length from the peak points of IRTL curve to the earth-quakes occurrence were three and nine months for the Ludian and Jinggu earth-quakes, respectively. Therefore it is deduced that the lowest point of IRTL curve in the stage of seismic quiescence and the peak point of JRTL curve in the stage of enhanced activity may be indicators of earthquake occurrence.