Mass movements and delta collapses are significant sources of tsunamis in lacustrine environments, impacting human societies enormously. Palaeotsunamis play an essential role in understanding historical events and their consequences along with their return periods. Here, we focus on a palaeo event that occurred during the Younger Dryas to Early Holocene climatic transition, ca., 12,000 years ago in the Lake Aiguebelette (NW Alps, France). Based on highresolution seismic and bathymetric surveys and sedimentological, geochemical, and magnetic analyses, a seismically induced large mass transport deposit with an initial volume of 767172 m3 was identified, dated and mapped. To investigate whether this underwater mass transport produced a palaeotsunami in the Lake Aiguebelette, this research combines sedimentary records and numerical models. Numerical simulations of tsunamis are performed using a viscoplastic landslide model for tsunami source generation and two-dimensional depth-averaged nonlinear shallow water equations for tsunami wave propagation and inundation modelling. Our simulations conclude that this sublacustrine landslide produced a tsunami wave with a maximum amplitude of approximately 2 m and run-up heights of up to 3.6 m. The modelled sediment thickness resulting from this mass transport corroborates well with the event deposits mapped in the lake. Based on our results, we suggest that this sublacustrine mass transport generated a significant tsunami wave that has not been reported previously to the best of our knowledge.

翻译：质量运动和三角洲坍塌是湖泊环境中海啸的重要来源，对社会产生巨大影响。古海啸在理解历史事件及其后果以及重现周期方面至关重要。本文聚焦于新仙女木期至早全新世气候转型期间（约12,000年前）发生在法国阿尔卑斯山西北部艾格贝莱特湖的一次古事件。基于高分辨率地震和测深调查，结合沉积学、地球化学和磁性分析，我们识别、定年和绘制了一处地震诱发的大型质量运输沉积物，其初始体积为767,172立方米。为探究这一水下质量运输是否在艾格贝莱特湖中引发了古海啸，本研究将沉积记录与数值模型相结合。采用黏塑性滑坡模型生成海啸源，并利用二维深度平均非线性浅水方程进行海啸波传播和淹没模拟。数值模拟结果表明，此次湖底滑坡产生的海啸波最大振幅约2米，爬高可达3.6米。由质量运输模拟得出的沉积厚度与湖中绘制的沉积事件吻合良好。基于我们的结果，我们认为此次湖底质量运输产生了一次显著的海啸波，据我们所知，此前尚未有相关报道。