The 2008 Mw 7.9 Wenchuan earthquake triggered plenty of coseismic giant landslides, which resulted in almost one third of total fatalities and economic losses during the event. Previous studies investigated the spatial relations between landslide distribution and topographic and seismic factors such as elevation, slope aspect, distance from rupture trace and seismic intensity. However, few studies are performed exploring the effects of coseismic surface deformation and Coulomb stress change on triggering landslides due to lack of adequate deformation observation data and stress calculation model for slope failure. In this study, we develop an envelope method to map an entire coseismic deformation field in both near- and far-field areas of seismic faults through the data fusion from InSAR and pixel offset-tracking (POT) techniques. The change in static Coulomb stress (SCS) acting on coseismic landsliding surface caused by the event is determined using the faulting model derived from the joint inversion of InSAR and GPS data, and also with the use of the elastic half-space dislocation theory and the generalized Hook’s law. The analysis suggests the spatial response pattern of seismic landslides to the coseismic ground motion and stress change, especially in the vicinity of fault rupture trace. The landslide density dramatically rises with the stress increase within the range from Yingxiu to Beichuan areas along the major surface rupture. Moving further and eastward along the fault strike, most of large landslides are triggered as the zone of positive SCS change narrows. Moreover, the high-magnitude surface displacements are possibly responsible for the giant landsliding events in the easternmost section. From the analysis of the stress transfer, the occurrence of landslides in the study area is largely controlled by the Yingxiu-Beichuan fault with overwhelming rupture length and fault slip, yet the Pengguan fault indeed shows dominance in the area between the two faults. The results show that coseismic surface deformation (derived from InSAR data in this study) and static Coulomb stress change can serve as two significant controlling factors on seismic landslide distribution and that the stress factor seems more significant in the vicinity of surface rupture.

2008年汶川7.9级地震引发了许多同震巨大的山体滑坡，造成了死亡人数和经济损失的近三分之一。先前的研究调查了滑坡分布与地形和地震因素之间的空间关系，例如海拔，坡度，距破裂轨迹的距离和地震烈度。然而，由于缺乏足够的变形观测数据和边坡破坏的应力计算模型，很少有研究探讨同震表面变形和库仑应力变化对触发滑坡的影响。在这项研究中，我们开发了一种包络法，通过InSAR和像素偏移跟踪（POT）技术的数据融合，在地震断层的近场和远场区域中绘制整个同震形变场的图。由事件引起的作用于同震滑坡表面的静态库仑应力（SCS）的变化是使用InSAR和GPS数据联合反演得出的断层模型，以及弹性半空间位错理论和广义的胡克定律 分析表明，地震滑坡对同震地面运动和应力变化的空间响应模式，尤其是在断层破裂迹线附近。沿主要地表破裂，在映秀至北川地区，随着应力的增加，滑坡密度急剧增加。沿断层走向进一步向东移动，随着SCS正变化带的变窄，大多数大型滑坡被触发。此外，高幅地表位移可能是最东段巨大的滑坡事件的原因。从应力传递的分析来看，研究区的滑坡发生主要由英秀—北川断裂带控制，其破裂长度和断层滑动都以压倒性优势存在，而鹏观断裂确实在这两个断裂带之间的区域中占主导地位。结果表明，同震表面变形（来自本研究的InSAR数据）和静态库仑应力变化可以作为影响地震滑坡分布的两个重要控制因素，应力因素在地表破裂附近似乎更为显着。该研究区的滑坡发生主要受映秀—北川断裂带控制，其断裂长度和断裂带具有压倒性优势，而澎关断裂带确实在这两个断裂带之间的区域中占主导地位。结果表明，同震表面变形（来自本研究的InSAR数据）和静态库仑应力变化可以作为影响地震滑坡分布的两个重要控制因素，应力因素在地表破裂附近似乎更为显着。该研究区的滑坡发生主要受映秀—北川断裂带控制，其断裂长度和断裂带具有压倒性优势，而澎关断裂带确实在这两个断裂带之间的区域中占主导地位。结果表明，同震表面变形（来自本研究的InSAR数据）和静态库仑应力变化可以作为影响地震滑坡分布的两个重要控制因素，应力因素在地表破裂附近似乎更为显着。