Rock slopes and rock avalanches in glacial environments of NW North America

北美西北部冰川环境中的岩石斜坡和岩石雪崩

• 批准号: RGPIN-2014-04631
• 负责人: Evans, Stephen
• 金额: $ 2.19万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=650349
• 关键词: Rock; slopes; rock; avalanches; glacial

As events in the mountains of British Columbia (BC) in 2010 and Alaska in 2012 have indicated, rock slopes in glacial environments are particularly prone to catastrophic failure. The research proposed here will investigate the occurrence, behaviour and geomorphic impacts of rock avalanches originating in rock slopes adjacent to glaciers (periglacial rock slopes) and which run for all or part of their travel on the glacier surface itself. The investigation focuses on rock slopes and rock avalanches in the glacial environment of the western part of the Cordillera of NW North America (western Washington, western BC, southwestern Yukon, and southern Alaska). Our data indicates that at least 55 rock avalanches of 1M m3 or greater in volume have occurred in the region since 1945 in three glacierised topographic/geologic settings (Quaternary Volcanic Centres, the BC Coast Mountains and the mountains of southern Alaska, SW Yukon, and NW BC). We note that the study area has an extensive glacier cover that has undergone dramatic climate-change-related ice loss since ca. 1900; our analysis will assume that the regionally-coherent glacier ice loss is an appropriate proxy for climate change. The research will utilise a novel integration of GPS-assisted field investigation, cutting-edge remote sensing and satellite technology, and advanced analytical software to establish a complete inventory of rock avalanches in the three glacier environments of the region from 1945 to 2013, determine its spatio-temporal signature, analyse the geomechanics of initial failure (including topographic controls and the role of glacier surface lowering), detect and measure periglacial rock slope deformation by satellite Synthetic Aperture Radar interferometry (InSAR), characterise the geometry and behaviour of rock avalanches and their deposits, evaluate the contribution of rock avalanches to periglacial rock slope denudation and to measure the relative contribution of seismic and climate forcing to volumetric rock loss from periglacial rock slopes. Five questions are of particular current interest; i) does a climate change signal exist in rock avalanche spatio-temporal occurrence as suggested by much recent literature? ii) to what extent is this amplified or offset by seismic forcing? iii) what is the precise contribution of rock avalanche-related rock slope denudation to high rates of glacial erosion in the region and to the so-called "glacial buzzsaw" denudation mechanism (i.e., relief destruction above the perennial snowline), iv) what is the spatial and hypsometric distribution of non-catastrophic periglacial rock slope movements and, v) what proportion (and under what conditions) of these deforming periglacial slopes experience catastrophic failure? Building on the successes of landslide and remote sensing research at Waterloo, the 5-year research programme addresses Canada's critical shortage of highly-qualified people in the fields of landslide research, engineering geomorphology, quantitative earth observation, and analytical remote sensing through the multi-skill training of 4 PhD and 2 MSc students by March 31, 2019. In this training, each student will address a working objective (or group of objectives) identified in the research proposal, participate in at least one major geoscience conference during their research, and make key co-author contributions to scientific papers submitted to peer-reviewed journals. The resultant infusion of expertise will help position Canada to utilise the flood of earth observation data on its mountain environments generated by increased accessibility to existing satellite products and the data stream from near-future satellite launches (ESA's Sentinel 1 (2014) and Canada's RADARSAT Constellation Mission (RCM) (2018)).

正如2010年不列颠哥伦比亚省和2012年阿拉斯加山区发生的事件所表明的那样，冰川环境中的岩石边坡特别容易发生灾难性的破坏。这里提议的研究将调查起源于冰川附近岩石斜坡（冰缘岩石斜坡）的岩石雪崩的发生、行为和地貌影响，这些岩石雪崩的全部或部分行程都在冰川表面上进行。调查的重点是北美西北部科迪勒拉山脉西部（华盛顿西部、公元前西部、育空地区西南部和阿拉斯加南部）冰川环境中的岩石斜坡和岩石雪崩。我们的数据表明，自1945年以来，在三个冰川化的地形/地质环境（第四纪火山中心、不列颠哥伦比亚海岸山脉和阿拉斯加南部、西南育空地区和西北不列颠哥伦比亚山脉）中，该地区至少发生了55次体积为100万立方米或更大的岩石雪崩。我们注意到，研究区域有一个广泛的冰川覆盖，经历了戏剧性的气候变化相关的冰损失，因为约。1900年;我们的分析将假设区域一致的冰川冰损失是气候变化的适当代理。该研究将利用GPS辅助实地调查，尖端遥感和卫星技术以及先进的分析软件的新颖集成，建立该地区1945年至2013年三个冰川环境中岩石雪崩的完整清单，确定其时空特征，分析初始破坏的地质力学（包括地形控制和冰川表面下降的作用），利用卫星合成孔径雷达干涉测量技术（干涉合成孔径雷达）探测冰缘岩质边坡变形，研究岩崩及其堆积物的几何形态和行为，评估岩石崩塌对冰缘岩坡剥蚀的贡献，并测量地震和气候强迫对冰缘岩坡岩石体积损失的相对贡献。五个问题是特别当前感兴趣的，i）气候变化信号存在于岩石雪崩的时空发生的建议，最近的文献？ ii）地震作用力在多大程度上放大或抵消了这种影响？iii）与岩石雪崩有关的岩石斜坡剥蚀对该地区高速率的冰川侵蚀和所谓的“冰川电锯”剥蚀机制（即，常年雪线以上的地形破坏），iv）非灾难性冰缘岩坡运动的空间和高程分布是什么，v）这些变形的冰缘岩坡经历灾难性破坏的比例（以及在什么条件下）？在滑铁卢滑坡和遥感研究的成功基础上，为期5年的研究计划通过2019年3月31日之前对4名博士和2名硕士学生进行多技能培训，解决了加拿大在滑坡研究，工程地貌学，定量地球观测和分析遥感领域严重缺乏高素质人才的问题。在这项培训中，每个学生将解决研究提案中确定的工作目标（或一组目标），在研究期间参加至少一次主要的地球科学会议，并为提交给同行评审期刊的科学论文做出关键的共同作者贡献。由此产生的专业知识的注入将有助于加拿大利用现有卫星产品的可访问性增加所产生的大量山区环境地球观测数据和不久的将来卫星发射的数据流（欧空局的哨兵1号（2014年）和加拿大的雷达卫星星座使命（RCM）（2018年））。