摘要
2019年11月11日的Mw 4.9 Le Teil地震是法国东南部罗纳河谷地区历史上破坏性最大的地震。基于哨兵1号卫星数据,利用GAMMA软件提取了该地震同震形变场。根据同震形变场,采用贝叶斯算法和最速下降法分别反演了断层几何参数和断层滑动分布。利用2000年和2006—2011年的两期数字高程模型数据估算了断层附近采石场开采量,并根据三维均匀弹性半空间的Boussinesq解求得由采石活动所造成的断层面上的库仑应力变化。结果表明,升降轨卫星视线向最大垂直位移分别为14.9 cm和8.6 cm。Le Teil地震是倾角72°、走向54°、平均滑动角约108°的高角度逆冲型地震;地震破裂到地表,破裂面积约3 413 m×1 358 m,最大破裂深度约为1.472 km;断层最大滑动量0.2 m,主滑动量(> 0.15 m)集中于0~0.75 km深度范围内;反演得到的矩震级为Mw 4.79。断层面上的库仑应力变化显示库仑应力在2000年以后的6~11年内增加了0.024 MPa。Le Teil采石场在1833—2019年被持续开采,且2007年以来,采石速率迅速增大。若考虑整个采石周期,则库仑应力变化可达0.1 MPa,远大于该地区的构造加载速率,表明2019年Le Teil地震与采石活动密切相关。
Objectives:The Mw 4.9 Le Teil earthquake that occurred on November 1l,2019 is the most destructive earthquake recorded in the Rhone River Valley of France.Methods:We first used Sentinel-1 data to calculate the coseismic displacement field of the Le Teil earthquake with the GAMMA software package.We then obtained fault geometric parameters and coseismic displacement fields based on Bayesian inversion and the steepest descent method(SDM).We last quantified the effects of quarry extraction activi-ty on fault by using the digital elevation model(DEM)data acquired in 2000 and 2006-2011.We calculated the extraction volume and the Coulomb stress change on the fault plane based on the Boussinesq solution of three dimension homogeneous and elastic half-space.Results:The coseismic displacement field show that the largest displacements in the line of sight of the ascending and descending orbits are 14.9 cm and 8.6 cm,respectively.We find that the seismogenic fault has a southeast dip angle of 72°,a strike of 54°and an average rake of 108°;the earthquake rupture reached the surface,with a rupture area of about 3413 mX1358 m,and a depth of about 1.472 km.The slip is over 0.15 m and is concentrated at a depth of 0-0.75 km with a peak slip of 0.2 m.We calculated the geodetic magnitude to be Mw 4.79.The Coulomb stress change on the fault plane is 0.024 MPa in 6-11 years after 2000.Conclusions:The rock extraction of the Le Teil quarry had been active during 1833-2019,and the extraction is even more intense after 2007.The Coulomb stress change on the fault plane could reach up to O.1 MPa,which is much larger than the local tectonic loading rate,suggesting that the Le Teil earthquake is strongly related to rock extraction activities.
作者
马升龙
周宇
沈旭章
MA Shenglong;ZHOU Yu;SHEN Xuzhang(Guangdong Provincial Key Laboratory of Geodynamics and Geohazards,School of Earth Sciences and Engineering,Sun Yat-Sen University,Zhuhai 519000,China)
出处
《武汉大学学报（信息科学版）》
EI
CAS
CSCD
北大核心
2024年第7期1190-1200,共11页
Geomatics and Information Science of Wuhan University
基金
第二次青藏高原综合科学考察研究(2019QZKK0901)
国家自然科学基金(41874020)
广东省引进人才创新创业团队(2016ZT06N331)。
关键词
Le
Teil地震
哨兵1号
滑动分布反演
采石活动
库仑应力变化
地震触发
Le Teil earthquake
Sentinel-l
slip distribution inversion
rock extraction activity
coulomb stress change
earthquake triggering
