利用GPS数据估算川滇南部地震(M_S≥6.5)平均复发间隔  

Quantitative estimation of recurrence intervals of the M_S≥6.5 earthquakes in southern Sichuan-Yunnan region using GPS observations

作　　者：张效亮[1,2] 谢富仁[1] 史保平[3] 

机构地区：[1]中国地震局地壳应力研究所,中国北京100085 [2]中国地震灾害防御中心,中国北京100029 [3]中国科学院研究生院地球科学学院,中国北京100049

出　　处：《地震学报》2010年第1期23-32,共10页Acta Seismologica Sinica

基　　金：国家科技支撑项目专题(2006BAC13B01-03)<大震复发周期与年平均发生率评价技术>;中国区划图编制项目(2007)资助

摘　　要：利用川滇南部GPS站点速度资料,采用Kriging插值和有限单元中形函数(拉格朗日差值函数)求导原则,计算了川滇南部主应变速率.在此基础上,引入Kostrov地震矩率计算方法,由主应变速率求得了研究区的地震矩率,进而借助于Ward地震平均复发间隔公式计算了研究区地震(MS≥6.5)平均复发间隔.计算结果表明,川滇南部不同震级档地震复发间隔空间分布总体上与区内主要活动断裂展布基本吻合;地震复发间隔低值区主要分布在地震活动水平和滑动速率较高的安宁河—则木河—小江断裂带、丽江—小金河断裂西南段、红河断裂西北段.所得的结果与利用历史地震资料获得的结果基本一致.该方法对于历史地震资料缺乏或不完整地区和活动断层定量研究程度较低的地区有着潜在的应用价值.With a combination of the Kriging interpolation and shape function’s derivative （Lagrange interpolation function） used in finite element analysis,we have derived the elastic strain rate field in southern Sichuan-Yunnan region,China,based on the regional GPS velocity observations. Furthermore,the derived strain rate is directly converted into the seismic moment rate according to the Kostrov’s moment rate formula. By means of the Ward’s recurrence interval formula the recurrence intervals of MS≥6.5 earthquakes in southern Sichuan-Yunnan region are obtained numerically. The result shows that the contours of earthquake recurrence intervals generally coinside with the major fault zones. The low interval values are on the Anninghe-Zemuhe-Xiaojiang fault,the southwestern Lijiang-Xiaojinhe fault and the northwestern Red River fault,where the level of fault slip rate and earthquake activity is high. In general,the average earthquake recurrence intervals estimated in this paper are comparable with the intervals obtained from historical earthquake investigations. It should be pointed out that the methodology described in this paper has potential of application in modern seismic hazard assessment,especially for the regions being lack of instrumental and historical records.

关 键 词：GPS 地震复发间隔 应变率 地震矩率 川滇地区 

分 类 号：P315.727[天文地球—地震学]