Kremer Katrina, Fabbri Stefano C, Evers Frederic M, Schweizer Nora, Wirth Stefanie B
Swiss Seismological Service, ETH Zürich, Sonneggstrasse 5, 8092 Zurich, Switzerland.
Insitute of Geological Sciences and Oeschger Centre for Climate Change Research, Baltzerstrasse 1+3, University of Bern, 3012 Bern, Switzerland.
Swiss J Geosci. 2022;115(1):13. doi: 10.1186/s00015-022-00405-0. Epub 2022 Apr 9.
Mass movements constitute major natural hazards in the Alpine realm. When triggered on slopes adjacent to lakes, these mass movements can generate tsunami-like waves that may cause additional damage along the shore. For hazard assessment, knowledge about the occurrence, the trigger and the geomechanical and hydrogeological mechanisms of these mass movements is necessary. For reconstructing mass movements that occurred in or adjacent to lakes, the lakes's sedimentary record can be used as an archive. Here, we present a prehistorical mass-movement event, of which the traces were found in an alpine lake, Lake Thun, in central Switzerland. The mass movement is identified by large blocks on the bathymetric map, a chaotic to transparent facies on the reflection seismic profiles, and by a mixture of deformed lake sediments and sandy organic-rich layers in the sediment-core record. The event is dated at 2642-2407 cal year BP. With an estimated volume of ~ 20 × 10 m it might have generated a wave with an initial amplitude of > 30 m. In addition to this prehistorical event, two younger deposits were identified in the sedimentary record. One could be dated at 1523-1361 cal year BP and thus can be potentially related to an event in 598/599 AD documented in historical reports. The youngest deposit is dated at 304-151 cal year BP (1646-1799 AD) and is interpreted to be related to the artificial Kander river deviation into Lake Thun (1714 AD).
The online version contains supplementary material available at 10.1186/s00015-022-00405-0.
大规模山体滑坡是阿尔卑斯地区的主要自然灾害。当在湖泊附近的斜坡上引发时，这些大规模山体滑坡会产生类似海啸的波浪，可能会对沿岸造成额外破坏。对于灾害评估而言，了解这些大规模山体滑坡的发生情况、触发因素以及地质力学和水文地质机制是必要的。为了重建发生在湖泊内或湖泊附近的大规模山体滑坡，湖泊的沉积记录可作为档案使用。在此，我们展示了一个史前大规模山体滑坡事件，其痕迹在瑞士中部的图恩湖这一高山湖泊中被发现。通过测深图上的大块物体、反射地震剖面的混沌至透明相，以及沉积岩芯记录中变形的湖泊沉积物和富含有机质的砂层混合物来识别该大规模山体滑坡。该事件的年代测定为公元前2642 - 2407年。估计体积约为20×10立方米，它可能产生了初始振幅大于30米的波浪。除了这个史前事件外，在沉积记录中还识别出了两个较年轻的沉积物。其中一个可追溯到公元前1523 - 1361年，因此可能与历史报告中记载的公元598/599年的一个事件有关。最年轻的沉积物年代测定为公元304 - 151年（公元1646 - 1799年），被解释为与1714年人工将坎德河改道引入图恩湖有关。
在线版本包含可在10.1186/s00015 - 022 - 00405 - 0获取的补充材料。
