Annual to millennial landslide inventories and hillslope erosion in NW Argentine Andes

这项德国-阿根廷合作研究的重点是了解阿根廷西北部安第斯山脉的山体滑坡发生情况。该地区的特点是东西陡峭，北S环境梯度适中，气候和植被覆盖不断变化，此外，在地形和地形上也有明显的对比。该地区在构造上是活跃的，在过去6年中受到了两次地震(2010年6.3级和2015年5.8级)的影响，即在密集的光学和雷达遥感数据覆盖的时间框架内，因此有助于对影响滑坡的不同强迫因素进行严格分析。山坡过程，包括大型随机滑坡事件，对山脉的地貌演变至关重要，也是沉积物生成和运移到沉积盆地的关键。虽然构造性构造力是造山过程的原因，但物理过程(如地震的累积影响)和生物地球化学过程(如风化作用、生物群)强烈影响沉积物的生产和运输，并最终影响造山带的侵蚀衰变。作为罕见但往往规模巨大的事件，山体滑坡在这种组合过程中的作用还没有得到很好的理解。这是因为大型山体滑坡事件的频率往往超出了仪器记录。虽然以前的研究表明，滑坡在时间上的聚集可以由地震和/或降雨极端事件来解释，但其空间分布受到岩石破裂和剪切等预条件因素以及包括植被覆盖在内的环境因素的控制。在这里，我们开始检验假设和模型预测，即滑坡位置和质量传输率在很大程度上受植被覆盖和地质预适应因素的控制。虽然地震和降雨--极端事件及其潜在影响尚无法预测，但对滑坡发生地点的更全面了解将有助于评估高山地形不断变化的环境中的自然灾害。在第二步中，我们假设地球化学示踪剂可以对滑坡的发生进行更严格的评估。我们将使用地球化学示踪剂来测量景观不平衡，并调查现代对滑坡分布的观察是否可以延续到过去和地质档案中。为此，我们将使用原位和大气中的10-铍来量化千年侵蚀速率和景观不平衡。这将与遥感数据相结合，以生成过去15年(2001年至今)的滑坡和山坡不稳定时间序列，并最终阐明地震、气候和植被覆盖变化对滑坡事件的影响。

This collaborative German-Argentine study focuses on understanding the occurrence of landslides in the NW Argentine Andes. This region is characterized by a steep E-W and a moderate N-S environmental gradient of changing climate and vegetation cover, in addition to pronounced contrasts in topography and relief. This region is tectonically active and has been affected by two earthquakes in the past 6 years (M6.3 in 2010 and M5.8 in 2015), i.e. within a timeframe covered by dense optical and radar-remote sensing data, and thus lends itself to a rigorous analysis of different forcing factors that influence landsliding. Hillslope processes, including large stochastic landsliding events, are critical to the morphologic evolution of mountain ranges, and are key to the generation and transport of sediment into sedimentary basins. While constructive tectonic forces are responsible for mountain building processes, physical (e.g., the cumulative effect of earthquakes) and bio-geochemical (e.g., weathering, biota) processes strongly impact sediment production and transport, and ultimately, the erosional decay of orogens. The role of landslides in this combination of processes, as rare, but often voluminous events, is not well understood. This is because the frequency of large landsliding events is often beyond instrumental records. While previous studies suggest that the temporal clustering of landslides may be explained by earthquakes and/or rainfall-extreme events, their spatial distribution is controlled by preconditioning factors such as rock fracturing and shearing, and environmental factors, including vegetation cover. Here, we set out to test hypotheses and model predictions that landslide location and mass-transport rates are to a large degree controlled by vegetation cover and geologic preconditioning factors. While earthquake and rainfall-extreme events and their potential impacts cannot be predicted yet, a more holistic understanding of the locations of landsliding will aid in assessing natural hazards in the changing environments of high-mountain terrains. In a second step, we hypothesize that geochemical tracers allow a more rigorous assessment of landslide occurrences. We will use geochemical tracers to measure landscape disequilibrium and investigate if present-day observations of landslide distribution can be extended into the past and into geological archives. For this purpose we will quantify millennial erosion rates and landscape disequilibria using in-situ and meteoric 10-Beryllium. This will be combined with remote-sensing data, to generate a landslide and hillslope instability time series for the past 15 years (2001-present day) and to ultimately elucidate the impacts of earthquakes, climate, and vegetation-cover changes on landsliding events.