Collaborative Research: Tying deep-seated landslides to base level, earthquakes, and a changing climate in the Pacific Northwest

在华盛顿州人口稠密的普吉特海湾地区发现了数千个史前滑坡沉积物，2014年SR530“Oso”滑坡造成43人死亡。该地区还经历了其他灾害，如地震和冬季暴雨，这些灾害可能引发了许多史前的山体滑坡。该项目将全面绘制和估计过去滑坡的年龄，以确定哪些滑坡可能是由独立已知的地震和气候事件引发的，从而改进对未来事件的危害估计。计划与负责在太平洋西北地区制作滑坡灾害地图的国家机构进行协调，以确保广泛传播项目成果。一个重要的焦点将是将可能由西雅图断层的史前地震引发的山体滑坡与地震引起的地面震动的基于物理的计算机模拟联系起来。该项目将测试长期存在的概念模型，以确定山体滑坡发生的时间和地点，以响应三种主要的强迫机制：地震、气候和基准面。主要的技术目标是量化滑坡在空间和时间上的模式，并根据强迫机制的独立记录对这种模式进行评价。迄今为止，实现这一目标所需的数千次滑坡，研究人员将定义一个滑坡年龄的经验模型，该模型可以通过机载激光雷达数据有效地远程测量，并受已知基准滑坡年龄的限制。模拟西雅图断层地震情景的地面运动将与最近一次史前破裂可能引发的滑坡进行比较，以告知未来的危害估计和约束破裂参数。基于遥感的滑坡测年和三维地震模拟的新组合将促进对景观如何演变和产生危害的科学理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Thousands of prehistoric landslide deposits are found throughout the heavily populated Puget Sound region in Washington State, where the SR530 “Oso” Landslide killed 43 people in 2014. The region also experiences other hazards, such as earthquakes and heavy winter rain storms, that likely triggered many of those prehistoric landslides. This project will comprehensively map and estimate the ages of past landslides to determine which ones were likely triggered by independently known earthquakes and climatic events, thereby improving hazard estimates for future events. Coordination with state agencies responsible for creating landslide hazard maps in the Pacific Northwest is planned to ensure broad dissemination of project results. An important focus will be connecting landslides that may have been triggered by a prehistoric earthquake on the Seattle Fault to physics-based computer simulations of ground shaking caused by that earthquake.The project will test long-standing conceptual models for when and where landslides occur within the landscape in response to three main forcing mechanisms: earthquakes, climate, and base level. The main technical goal is to quantify the pattern of landslides in space and time and evaluate that pattern against independent records of forcing mechanisms. To date the thousands of landslides required to accomplish this goal, the researchers will define an empirical model for landslide age that can be efficiently measured remotely with airborne lidar data and constrained by known ages of benchmark landslides. Simulated ground motions from a suite of modeled Seattle Fault earthquake scenarios will be compared to landslides likely triggered by its most recent prehistoric rupture to inform future hazard estimates and constrain rupture parameters. The novel combination of remote sensing-based landslide dating and 3D earthquake simulations will advance scientific understanding of how landscapes evolve and generate hazards.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.