2015年4月25日，Mw7.8尼泊尔地震发生在喜马拉雅造山带中段，造成了惨重的人员伤亡和财产损失。研究表明，这次地震的主要破裂发生在1934年Mw 8.1比哈-尼泊尔地震和1505年Mw 8.2木斯塘地震之间的空区东段 5-15 km深度的断层面上，而这一空区西段和浅部断层面上没有发现明显的断层破裂。震间研究结果显示这些未破裂区域在尼泊尔地震前同样处于较强的闭锁状态，积累了明显的应变。因此，这些未破裂断层区域的地震危险性引发了广泛关注。前人研究表明，震后余滑也是断层所积累弹性应变的一种重要释放形式，对地震危险性的客观评估有重要影响。本项目拟利用大地测量观测的形变资料为约束，研究2015年尼泊尔地震的震后过程，获取断层余滑时空分布和下地壳/上地幔的粘滞性结构，为喜马拉雅造山带中段的地震危险性评估及强震孕育机理提供依据。

On April 25, 2015 an earthquake of Mw 7.8 occurred on the central segment of the Himalayas, which has caused heavy casualties and property loss. Co-seismic investigations show that the main rupture of the earthquake locates at the deep portion (5-15 km) of the eastern segment within the previously identified seismic gap, between the 1934 Bihar Mw 8.1 earthquake and the 1505 Lo Mustang Mw 8.2 earthquake. However, no clear slip was found at the western segment and at the shallow portion of the eastern segment. Interseismic studies indicate that the seismic gap, including the unruptured areas, was highly locked to accumulate seismic strain before the event. Therefore, nearby seismic hazard in future has caused widespread concern. Aseismic afterslip following the main shock has found to be another important way to release the accumulated seismic strain, which may highly affect the assessment of regional seismic hazard. The purpose of this project is to study postseismic deformation following the 2015 Nepal earthquake with incorporation of modern geodetic techniques, InSAR and GPS. Furthermore, we will investigate the related postseismic process, including the time-dependent afterslip and viscoelastic relaxation of the lower crust and upper mantle. The study will also enlighten regional seismic hazard assessment and seismogenic mechanisms of large earthquakes on the central segment of the Himalayas.