Towards a data-based and physics-based model of interseismic and seismic behavior of Main Himalayan Thrust

喜马拉雅山脉是中亚地震灾害的主要威胁，它使几个国家的人口稠密和经济面临危险。该项目将提供有关该地区地震活动的重要信息，更广泛地说，将推动在地震灾害研究中使用大地测量的方法。喜马拉雅地区最近和历史上的地震远远不能平衡目前喜马拉雅地区地震间应变的累积速度。因此，我们对瞬时地震如何释放震间应变，以及喜马拉雅主要逆冲断层上的非地震滑动可能是如何释放的看法是非常不完整的。该项目的长期目标是开发一个动态模型，并获取适当的数据，以验证和校准该模型，以评估喜马拉雅地区可能发生的各种地震情景及其发生的概率。为了实现这一目标，我们建议(1)继续监测和改进MHT上的地震间耦合模拟，(2)使用动态模拟来评估所需的断层摩擦特性，以解释观测到的地震间耦合模式，地震活动对长期和季节性应力的敏感性建立了(3)使用动力学模型来测试如何利用MHT锁定部分下倾边缘的应力聚集触发的小地震的统计数据来约束破坏整个锁定带的超大事件的统计数据(4)根据GRACE重力测量卫星任务测量的地表载荷变化引起的大地测量变形来约束地壳的粘性性质。

The Himalaya stands out as the major threat with respect to seismic hazard in central Asia where it puts at risk the dense population and economies of several countries. The project will contribute important information regarding seismic activity in that area and, more generally, will advance methods regarding the use of geodetic measurements in seismic hazard studies.Recent and historical earthquakes in the Himalaya fall way short of balancing the rate at which interseismic strain is currently accumulating in the Himalaya. Thus we have a very incomplete view of how interseismic strain is released by transient seismic, and possibly, aseismic slip on the Main Himalayan Thrust fault. The long term objective of this project is the development of a dynamic model and the acquisition of appropriate data to validate and calibrate the model that will allow assessing the full range of possible earthquake scenarios in the Himalaya and their probability of occurrence. To achieve that goal we propose (1) to keep on monitoring and improve the modeling of interseismic coupling on the MHT, (2) use dynamic modeling to evaluate the fault frictional properties needed to account for the observed pattern of interseismic coupling, the sensitivity of seismicity to secular and seasonal stress build up an (3) use dynamic models to test how the statistics of small earthquakes triggered by stress build up at downdip edge of the locked portion of the MHT can be used to constrain the statistics of the very large events rupturing the whole locked zone (4) constrain the viscous properties of the crust based on the geodetically measured deformation induced by surface load variations measured from the GRACE gravimetric satellite mission.