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

在气候变化之后，人们越来越需要在传统的物理危害评估模型中引入社会经济（SE）和关键基础设施（CI）的观点。高山灾害影响着全球一些最脆弱社区的生活。灾害的暴露程度和发生频率都有所增加，最严重的灾害是在山区普遍存在的山体滑坡和级联灾害。我们的目标是开发一个跨学科的分析框架，以识别和评估滑坡和级联冰川灾害对社区和生态系统的风险。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、旅游和宗教意义闻名的巴吉拉蒂和比兰加纳山谷实施和测试它。设计的工作流程融合了尖端的地球科学和社会科学研究，以开发新的见解，从而改善危害风险。针对目前喜马拉雅地区滑坡时空分布研究的空白，我们将在两个空间尺度上进行研究：(1)绘制、分析和理解滑坡的直接危险影响，(2)模拟冰川滑坡的间接但层叠的危险影响。除了对事件进行绘图和建模外，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一个多时间的滑坡清单，但我们也将使用树木地貌学方法将该清单扩展到过去~100年的时间尺度，推断出与极端天气、基础设施发展和气候变化相关的滑坡模式。此外，岩石特征/组成与滑坡破坏机制之间的关系还有待进一步研究。这种涵盖上述所有方面的高山流域滑坡整体和跨学科框架尚未被采用，可以为其他高山地区的类似研究树立一个基准。主要目标是：(1)利用地球观测（EO）数据和基于树木年轮的重建，建立一个时间上详尽的滑坡清单，并了解它们在极端天气事件和CI项目中的演变；(2)通过空间和人口分析评估滑坡对CI和居住的直接危害影响；(3)在确定的地点模拟冰川滑坡的级联危害潜力的影响。(4)进行岩土分析，以了解该地区边坡破坏与边坡物质组成和特征之间的关系；(5)了解社区对危害的感知（关于土地利用和迁移模式、贸易和迁移路线、亲属关系和联盟分布）；(6)设计基于社区和社会可接受的缓解准则。预期的结果将有利于高山社区，通过备灾和提高认识朝着减轻灾害的方向迈出一步。多时间滑坡清单将有助于评估当前和未来的灾害易发地区。社区对灾害的认识将进一步为决策者提供信息，以便在实施减灾措施时采取相应行动。基于树轮的过去频率序列重建将为基于过程的滑坡级联模拟模型的定标和精度评价提供良好的依据。对该地区边坡破坏机制与边坡物质组成及特征关系的进一步认识，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.