Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA.
Department of Geology, University of Maryland, College Park, MD, 20742, USA.
Sci Rep. 2019 Feb 7;9(1):1569. doi: 10.1038/s41598-018-38300-0.
The addition of water on or below the earth's surface generates changes in stress that can trigger both stable and unstable sliding of landslides and faults. While these sliding behaviours are well-described by commonly used mechanical models developed from laboratory testing (e.g., critical-state soil mechanics and rate-and-state friction), less is known about the field-scale environmental conditions or kinematic behaviours that occur during the transition from stable to unstable sliding. Here we use radar interferometry (InSAR) and a simple 1D hydrological model to characterize 8 years of stable sliding of the Mud Creek landslide, California, USA, prior to its rapid acceleration and catastrophic failure on May 20, 2017. Our results suggest a large increase in pore-fluid pressure occurred during a shift from historic drought to record rainfall that triggered a large increase in velocity and drove slip localization, overcoming the stabilizing mechanisms that had previously inhibited landslide acceleration. Given the predicted increase in precipitation extremes with a warming climate, we expect it to become more common for landslides to transition from stable to unstable motion, and therefore a better assessment of this destabilization process is required to prevent loss of life and infrastructure.
地表水的增加会导致地表应力发生变化，从而引发滑坡和断层的稳定和不稳定滑动。虽然这些滑动行为可以通过常用的机械模型来描述，这些模型是基于实验室测试开发的（例如，临界状态土壤力学和速率状态摩擦），但对于在从稳定滑动到不稳定滑动的转变过程中发生的现场尺度环境条件或运动行为，人们了解较少。在这里，我们使用雷达干涉测量（InSAR）和一个简单的一维水文学模型来描述 2017 年 5 月 20 日美国加利福尼亚州 Mud Creek 滑坡在快速加速和灾难性破坏之前 8 年的稳定滑动。我们的研究结果表明，在从历史干旱到创纪录降雨的转变过程中，孔隙流体压力大幅增加，这引发了速度的大幅增加，并导致滑动局部化，克服了此前抑制滑坡加速的稳定机制。考虑到气候变暖导致降水极值增加，我们预计滑坡从稳定到不稳定运动的转变将更为常见，因此需要更好地评估这种失稳过程，以防止生命和基础设施的损失。
