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

华盛顿州人口稠密的普吉特湾地区发现了数千处史前山体滑坡沉积物，2014年，那里发生的SR530山体滑坡导致43人死亡。该地区还经历了其他灾害，如地震和冬季暴雨，很可能引发了许多史前山体滑坡。该项目将全面绘制和估计过去山体滑坡的年龄，以确定哪些山体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险估计。计划与负责在太平洋西北地区编制滑坡危险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西雅图断层上可能由史前地震引发的山体滑坡与那场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性模型，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，并对照强迫机制的独立记录来评估这种模式。为了确定实现这一目标所需的数千个滑坡的日期，研究人员将定义一个滑坡年龄的经验模型，该模型可以利用机载激光雷达数据进行有效的远程测量，并受已知基准滑坡年龄的约束。从一套模拟的西雅图断层地震场景中模拟的地面运动将与最近的史前破裂可能引发的山体滑坡进行比较，以提供未来的危险估计和约束破裂参数。基于遥感的滑坡测年和3D地震模拟的新颖组合将促进对景观如何演变和产生危险的科学理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.