Rock slope behaviour and rock avalanches in glacial environments of NW North America

这项研究将调查岩石雪崩的发生、行为和地貌影响，这些雪崩起源于冰川附近的岩石斜坡（冰缘岩石斜坡），它们的全部或部分行程都在冰川表面上。这次调查的重点是北美西北部科迪勒拉山脉西部（包括华盛顿西部、不列颠哥伦比亚省西部、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，在三个冰川地形/地质环境中，该地区至少发生了55次体积为1M m3或更大的岩石雪崩，即第四纪火山中心（例如，喀斯喀特火山带（BC和华盛顿）），不列颠哥伦比亚省的海岸山脉和阿拉斯加南部山脉，育空地区西南部和BC西北部（例如，圣埃利亚斯山脉）。我们将建立1945年至2012年该地区三种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和地貌学（包括地形控制和冰川表面下降的作用），通过SAR干涉测量检测和测量冰周岩石边坡运动，表征岩石雪崩及其沉积物的几何形状和行为。评估岩石雪崩对冰缘岩石斜坡剥蚀的贡献，并测量地震和气候强迫对冰缘岩石斜坡体积岩石损失的相对贡献。有三个问题特别令人感兴趣：(1)在岩崩的时空发生中是否存在气候变化信号，正如最近的许多文献所表明的那样？Ii)地震强迫在多大程度上放大或抵消了这种影响？iii)与岩石雪崩相关的岩石坡面剥蚀对该地区高冰川侵蚀率和所谓的“冰川电锯”效应（即常年雪线或平衡线高度（ELA）以上的地形破坏）的确切贡献是什么？这个为期5年的研究项目通过培养4名博士和2名硕士学生，解决了加拿大在滑坡研究领域高素质人才的严重短缺问题。

The study 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 (including western Washington, western British Columbia (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, viz. Quaternary Volcanic Centres (e.g., the Cascade Volcanic Belt (BC and Washington)), the Coast Mountains of British Columbia and the mountains of southern Alaska, southwest Yukon, and NW BC (e.g., St Elias Mountains). We will establish a complete inventory of rock avalanches in the three glacier environments of the region from 1945 to 2012, determine its spatio-temporal signature, analyse the geomechanics and geomorphometrics of initial failure (including topographic controls and the role of glacier surface lowering), detect and measure periglacial rock slope movements by SAR interferometry, 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. Three questions are of particular 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" effect (i.e., relief destruction above the perennial snowline or equilibrium line altitude (ELA). The 5-year research programme addresses Canada's critical shortage of highly-qualified personnel in the field of landslide research through the multi-skill training of 4 PhD and 2 MSc students.