利用InSAR确定2009年4月6日MW6.3拉奎拉(Italy)地震最优震源模型  

Optimal source parameters of the 6 April 2009 Mw 6.3 L'Aquila,Italy earthquake from InSAR observations

作　　者：冯万鹏[1,2] 李振洪 李春来[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]Department of Geographical and Earth Sciences, University of GLasgow, Glasgow G12 8QQ, United Kingdom

出　　处：《地球物理学进展》2010年第5期1550-1559,共10页Progress in Geophysics

基　　金：中国地震局地球物理研究所中央级公益性科研院所基本科研业务专项(018903)基金资助

摘　　要：2009年4月6日意大利拉奎拉城附近发生了M_W6.3地震,造成了巨大人员伤亡和经济损失.本文利用欧洲空间局共享的ENVISAT ASAR卫星资料,生成了3幅独立的同震位移图像.采用当前流行的均匀网格、四叉树以及基于数据分辨率3种采样算法分别提取了4个独立的数据集(其中均匀网格算法采用2个不同的采样间隔),比较分析了这些不同数据资料约束下的单一断层反演参数的异同.通过变倾角迭代的方式,分析了最优单一断层与全局最优模型之间的几何参数的关系,确定了全局最佳拟合的滑动模型.该模型显示,这是一次正断层地震,断层几何中心位于(13.451°E,42.358°N),走向141°,倾角50°,倾向西南.最大滑动位于地表以下6.1km深度位置,约为1.2m;断层滑动未出露地表,上边界埋深约为3.1km;释放地震矩约合3.65×10^(18)N·m.On 6th April 2009 a MW6.3 earthquake occurred in the L＇ Aquila region, central Italy, causing at least 297 fatalities and great economic losses. Using European Space Agency＇s ENVISAT ASAR data we generated three independent coseismic interferograms. Three popular downsampling techniques （uniform, quadtree and Resolution-based） were employed to create 4 different sets of datapoints, two of which were produced using the uniform approach with different sampling sizes. Uniform models with the 4 sets of datapoints show similar source parameters and residuals, indicating their impacts on uniform modeling are limited. However, their distributed slip models suggest that the resolution-based approach is preferred though similar slip patterns can be observed. Our optimal distributed slip model shows that this event is associated with a buried SW-dipping normal fault with the epicenter at （13.4506°,42.3580°）,a strike of 141.3°, and a dip of 50°. In addition, the maximum slip of 1.2 m is observed at a depth of 6.1 km, and the total seismic monent is ~3.65×1018N·m.

关 键 词：INSAR 拉奎拉地震 四叉树算法 基于空间分辨率采样 震源反演 

分 类 号：P315.73[天文地球—地震学]