2015年尼泊尔Gorkha M_W7.9地震与Kodari M_W7.3地震InSAR数据反演及其应力触发分析

发布时间：2018-05-12 20:57

本文选题：尼泊尔Gorkha + MW.地震　；参考：《地震地质》2017年01期

【摘要】：根据喜马拉雅断裂系的构造形态,采用缓倾角反铲型断层模型模拟MHT上地震破裂部分的坡坪式发震构造。利用Alos-2及Sentinel-1获取的InSAR数据,反演获得了2015年尼泊尔Gorkha地震及其最大余震Kodari地震的同震滑动分布模型。与单独利用Alos-2或Sentinel-1 InSAR数据的反演结果相比,利用Alos-2和Sentinel-1 InSAR数据联合反演能够提供Gorkha地震破裂的更多细节信息,尤其对深部信息的约束更加明显。联合反演得到的破裂深度最大可达24km,穿过了该区域的闭锁线,到达了闭锁和蠕滑的转换区域。反演的断层模型倾角在3°~10°之间,最大滑动量出现在地下17km处,约4.5m。Gorkha地震和Kodari地震发震性质相似,都是发生在MHT断层上的低角度逆冲型地震,其中Gorkha地震略带右旋分量。反演结果还显示,Gorkha地震与Kodari地震的破裂滑动在空间上存在互补性,Kodari地震就发生在Gorkha地震的破裂空区内。通过计算Gorkha地震对Kodari地震发震断层的库仑破裂应力加载,发现Kodari地震震中恰位于库伦破裂应力正负交界区域,库仑破裂应力加载达0.4MPa,表明Kodari地震可能受到了Gorkha地震的触发。
[Abstract]:According to the structural form of the Himalayan fault system, the slope flat type seismogenic structure of the earthquake rupture part on MHT is simulated by using the slowly dip back-shovel fault model. Based on the InSAR data obtained by Alos-2 and Sentinel-1, the coseismic sliding distribution model of the 2015 Nepal Gorkha earthquake and its largest aftershock Kodari earthquake is obtained by inversion. Compared with the inversion results using Alos-2 or Sentinel-1 InSAR data alone, the joint inversion of Alos-2 and Sentinel-1 InSAR data can provide more detailed information of the Gorkha earthquake rupture, especially the constraint on the deep information is more obvious. The maximum fracture depth obtained by the joint inversion is up to 24km, which passes through the locking line of the region and reaches the conversion area of the latching and creeping. The inverse fault model has a dip angle between 3 掳and 10 掳, and the maximum slip occurs in the underground 17km. The 4.5m.Gorkha earthquake and the Kodari earthquake have similar seismogenic properties. They are both low-angle thrust earthquakes occurring on the MHT fault, in which the Gorkha earthquake belt is slightly right-handed. The inversion results also show that the rupture slip between the Gorkha earthquake and the Kodari earthquake is complementary to that of the Gorkha earthquake in the rupture gap zone. By calculating the Coulomb rupture stress loading of the Kodari seismogenic fault by the Gorkha earthquake, it is found that the Kodari earthquake epicenter is located at the positive and negative junction of the Coulomb rupture stress, and the Coulomb rupture stress loading reaches 0.4 MPa, indicating that the Kodari earthquake may be triggered by the Gorkha earthquake.
【作者单位】：中国石油大学(华东)地球科学与技术学院;中国地震局地质研究所地震动力学国家重点实验室;新疆维吾尔自治区地震局;
【基金】：中国地震局地质研究所基本科研业务专项(LED2014A01) 国家自然科学基金(41541031,41474013,4141101073,41340008)共同资助
【分类号】：P315.727

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