2014年云南地区GNSS面应变时空演化与M≥6.0地震关系

Relationship between Spatiotemporal Evolution of GNSS Surface Strain and Earthquakes of M≥6.0 in Yunnan Area in 2014

摘要:

通过对2014年云南地区43个GNSS连续跟踪站的站点时间序列原始数据进行深加工处理，获取区域面应变参数。固定2014年1月1日为起始时间，以4天为窗长进行滑动求解，获取不同时间节点的区域面应变变化特征。以盈江6.1级、鲁甸6.5级和景谷6.6级地震为样本，对GNSS面应变时空演化与M≥6.0地震的关系进行深入分析。结果表明，盈江6.1级、鲁甸6.5级和景谷6.6级地震与GNSS面应变收缩区的动态变化对应关系明显，3次强震发生前，在震中区周边出现了明显的面收缩增强现象，且存在较大范围的压性活动增强区域。震前应变场大幅调整，部分区域变化显著，可能是M≥6.0地震发生前的重要特征。从震中分布来看，3次地震均发生在面收缩增强区，推测面应变挤压增强可能更有利于强震的诱发。

Abstract:

In this paper,the point surface displacement data of 43 GNSS continuous tracking stations in Yunnan region in 2014 were deeply processed in order to obtain the regional surface strain parameters. By taking the starting date of January 1,2014 and ending the sliding time with a window length of 4 days,the regional surface strain change characteristics at different time nodes were obtained. Based on the Yingjiang M_S6.1,Ludian M_S6.5,and Jinggu M_S6.6 earthquakes as samples,the relationship between the spatiotemporal evolution of GNSS surface strain and M ≥ 6.0 earthquakes was analyzed. The results show that the Yingjiang M_S6.1,Ludian M_S6.5,and Jinggu M_S6.6 earthquakes are strongly related with the dynamic changes of the GNSS plane strain shrinkage area. Before these three strong earthquakes,a large area of contraction and enhancement appeared around the epicentral area,and there was a large area of enhanced compressive activity. The pre-earthquake strain field was greatly adjusted,and significant regional changes may be important features before M ≥ 6.0. From the perspective of epicenter distribution,all three earthquakes occurred in the area of enhanced surface contraction,and the enhancement of surface strain compression may be more conducive to the induction of strong earthquakes.