An interdisciplinary analytical framework for high-mountain landslides and cascading hazards: implications for communities and infrastructure

在气候变化之后，越来越需要将社会经济(SE)和关键基础设施(CI)视角纳入传统的物理危害评估模型。高山灾害影响到全球一些最脆弱社区的生活。山体滑坡和层叠灾害等灾害的风险暴露和发生频率有所增加，在山区最为普遍。我们的目标是建立一个跨学科的分析框架，以确定和评估山体滑坡和级联冰川灾害对社区和CI造成的风险。虽然该框架将适用于任何高山地区，但我们将在以水文、水电、旅游和宗教意义而闻名的Bhagirathi和BHilangana Vallees实施和测试它。设计的工作流程融合了前沿的地球科学和社会科学研究，以开发新的见解，从而能够改善灾害风险。针对喜马拉雅地区滑坡时空传播的现有研究空白，我们的研究将在两个空间尺度上进行：(1)绘制、分析和了解滑坡的直接危险影响，以及(2)模拟冰川滑坡的间接但连锁的危险影响。除了绘制事件图和建立事件模型外，该项目还在评估和缓解计划中纳入了SE和CI因素以及社区的看法。虽然我们将使用过去20年的高分辨率卫星数据集来生成多时相滑坡清单，但我们也将使用树状地貌学方法将该清单扩展到过去约100年的时间尺度，推断与极端天气、基础设施发展和气候变化有关的滑坡模式。此外，岩石特征/成分与滑坡破坏机制的关系还有待进一步研究。这种涵盖高山集水区滑坡所有上述方面的整体和跨学科框架尚未被采用，并可为其他高山地区的类似研究设定基准。主要目标是：(1)利用地球观测(EO)数据和基于树轮的重建开发一份时间上详尽的滑坡清单，并了解其相对于极端天气事件和CI项目的演变；(2)通过空间和人口分析评估滑坡对CI和居住的直接危险影响；(3)对已确定地点的冰川滑坡的级联危险潜力的影响进行建模，(4)进行岩土分析，以了解斜坡崩塌与该地区斜坡材料组成和特征之间的关系；(5)了解社区对灾害的认知(关于土地利用和交通运输模式、贸易和迁徙路线、亲属和联盟分布)；以及(6)设计基于社区和社会可接受的缓解准则。预期结果将有利于高山社区，通过备灾和提高认识向缓解迈出一步。多期滑坡调查将有助于评估当前和未来的灾害易发地区。社区对危险的感知将进一步告知政策制定者在实施缓解措施时采取相应行动。基于树轮的历史频率序列重建将为基于过程的滑坡梯级模拟模型的标定和精度评估奠定良好的基础。作为未来岩土工程勘察的一个展望，加深对该地区边坡破坏机理与坡体物质组成和特性关系的认识，将有助于建立可靠的滑坡预测岩土模型。

In the wake of climate change, there is an ever-increasing need to bring socioeconomic (SE) and critical infrastructure (CI) perspectives within conventional physical hazard assessment models. High-mountain hazards impact lives of some of the most vulnerable communities globally. The exposure to and the frequency of hazards have increased and are highest for events such as landslides and cascading hazards, prevalent in mountains. We aim at developing an interdisciplinary analytical framework for identifying and assessing the risks to communities and CI from landslides and cascading glacial hazards. While the framework will be applicable to any high-mountain region, we will implement and test it for Bhagirathi and Bhilangana Valleys, known for their hydrological, hydropower, touristic, and religious significance. The designed workflow blends cutting-edge geoscience and social science research to develop new insights enabling the amelioration of the hazard risks.Targeting the existing research gap on spatiotemporal spread of landslides in Himalaya, our research will be performed at two spatial scales: (1) mapping, analysing, and understanding the direct hazardous impacts of landslides, and (2) modelling the indirect but cascading hazardous impacts of glacial landslides. In addition to mapping and modelling the events, the project also incorporates SE and CI factors, and community perceptions within the assessment and mitigation plans. While we will use high-resolution satellite datasets of past ~20 years to generate a multi-temporal landslide inventory, we will also use dendrogeomorphology methods to extend this inventory to past ~100 years of timescale, deducing the landslide patterns with respect to extreme weather, infrastructure development, and climate shifts. Furthermore, the relationship between rock characteristics/composition and the landslide failure mechanism needs more investigations. Such holistic and interdisciplinary framework covering all the aforementioned aspects on landslides for a high-mountain catchment is yet to be adopted and can set a benchmark for similar research in other high-mountain regions.The main objectives are: (1) to develop a temporally exhaustive landslide inventory using Earth Observation (EO) data and tree ring-based reconstructions, and understand their evolution with respect to extreme weather events and CI projects, (2) to assess the direct hazard impact of landslides on CI and habitation through spatial and demographic analyses, (3) to model the impacts of cascade hazard potential of glacial landslides at the identified sites, (4) to perform geotechnical analysis to understand the relationship between slope failure and slope material compositions and characteristics in this region, (5) to understand the community perception of hazards (with respect to land use and transhumance patterns, trade and migration routes, and kinship and alliance distributions), and (6) To design community-based and socially acceptable mitigation guidelines.The anticipated outcomes will be beneficial to high-mountain communities, taking a step towards mitigation through preparedness and increased awareness. The multi-temporal landslide inventory will help assess the hazard-prone regions for present and future CI. The community perception of hazards will further inform policy makers on acting accordingly while implementing the mitigation measures. The tree-ring-based reconstruction of past frequency series will serve as an excellent basis for the calibration and accuracy assessment of process-based landslide cascade simulation models. As a future prospect of the geotechnical investigations, the improved understanding on the relationship between slope failure mechanism and slope material compositions and characteristics in this region, will help develop reliable geotechnical models on landslide prediction.