Imaging the Spatial and Temporal Evolution of Frictional Asperities Along the Failure Surface of Creeping Landslides to Illuminate the Mechanics of landslide Friction

对蠕动滑坡破坏面摩擦粗糙度的时空演化进行成像，以阐明滑坡摩擦力学

• 批准号: 2222149
• 负责人: Noah Finnegan
• 金额: $ 63.62万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2222149&HistoricalAwards=false
• 关键词: Imaging; Spatial; Temporal; Evolution; Frictional

Some landslides creep steadily for years or decades. In others, the creep appears similar, then abruptly transitions to catastrophic failure. Distinguishing these two scenarios is crucial for landslide hazard mitigation. However, the mechanistic origins of landslide friction remain unclear, which limits our understanding of how, when, and why landslides sometimes accelerate catastrophically, whereas others creep for decades. This project will advance understanding of landslide friction by combining deformation measurements and seismology at two distinct sites that most likely represent the two scenarios above. One is a well-studied slow landslide (Oak Ridge earthflow in California), while the other is a newly identified slow landslide near Columbia Glacier in Alaska. Whereas Oak Ridge earthflow has exhibited slow sliding for nearly a century, the Columbia Instability is in a setting where the investigators expect that glacier debuttressing of the slope will lead to acceleration and possibly catastrophic failure. The project has implications for natural hazard assessment and mitigation. The team will produce a short science documentary, create a public map of Prince William sound, coordinate among state and federal agencies, and train one PhD student.This project aims to advance understanding of why frictional asperities in landslides sometimes coalesce catastrophically, whereas others remain distinct, permitting creep for decades despite velocity-weakening friction. Currently there is very little monitoring of landslides over the temporal and spatial scales that would be required to more clearly illuminate the mechanics of landslide friction. This project will aim to bridge this gap by combining deformation monitoring and seismology at a well-studied and well-instrumented slow landslide (Oak Ridge earthflow in California) and an incipient bedrock failure near Columbia Glacier in Alaska. Whereas Oak Ridge earthflow has exhibited stable creep for nearly a century, the Columbia glacier site is in a setting where the slope will likely undergo acceleration due to glacial debuttressing, and this acceleration may lead to catastrophic failure. Field deployments will focus on imaging the spatial and temporal evolution of slip and micro-seismicity in two settings in order to 1) test at Oak Ridge between two different models for how frictional creep associated with stick-slip motion is possible in landslides, and 2) understand at Columbia glacier how velocity weakening asperities grow as creep accelerates due to glacial debuttressing - a process that sometimes culminates in catastrophic failure.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.

一些山体滑坡会持续数年或数十年。在其他情况下，蠕变看起来类似，然后突然过渡到灾难性的故障。区分这两种情况是至关重要的滑坡灾害减灾。 然而，滑坡摩擦的机械起源仍然不清楚，这限制了我们对滑坡如何，何时以及为什么有时会灾难性地加速，而另一些则会持续数十年的理解。 该项目将通过结合两个不同地点的变形测量和地震学来促进对滑坡摩擦的理解，这两个地点最有可能代表上述两种情况。一个是经过充分研究的缓慢滑坡（加州的橡树岭泥石流），另一个是最近发现的阿拉斯加哥伦比亚冰川附近的缓慢滑坡。尽管橡树岭的泥石流已经缓慢滑动了近世纪，但哥伦比亚的不稳定性是在一个环境中，调查人员预计冰川对斜坡的去支撑将导致加速和可能的灾难性失败。该项目对自然灾害评估和减灾具有影响。该团队将制作一个简短的科学纪录片，创建一个威廉王子湾的公共地图，协调州和联邦机构，并培训一名博士生。该项目旨在促进理解为什么滑坡中的摩擦粗糙体有时会灾难性地合并，而其他人仍然不同，尽管速度减弱摩擦，但仍允许蠕变数十年。 目前，在时间和空间尺度上对滑坡的监测很少，而这是更清楚地阐明滑坡摩擦力学所必需的。该项目旨在通过结合变形监测和地震学，在一个经过充分研究和仪器完善的缓慢滑坡（加州的橡树岭泥石流）和阿拉斯加哥伦比亚冰川附近的初期基岩破坏中弥补这一差距。而橡树岭泥石流已表现出稳定的蠕变近世纪，哥伦比亚冰川网站是在一个设置的斜坡可能会经历加速由于冰川去支撑，这种加速可能会导致灾难性的故障。现场部署将侧重于对两种情况下的滑动和微震活动的时空演变进行成像，以便：1）在橡树岭测试两种不同模型之间的摩擦蠕变如何与滑坡中的粘滑运动相关，2）了解哥伦比亚冰川的速度减弱粗糙体如何随着冰川去支撑作用导致的蠕变加速而增长-这个奖项反映了NSF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。