Earthquake- induced Geomorphology: A Neotectonic Study at the Front of the Alps (Lake Thun & Aare Valley, Switzerland)

We present a multi-disciplinary two-step approach to assess the potential for seismic hazard of the Aare valley and perialpine Lake Thun (Switzerland). High-resolution seismic images and multibeam-bathymetric data, complemented by field observations represent the tools to identify potentially active seismogenic fault structures. Several second-order earthquake effects such as subaqueous mass movements, seismites and liquefaction structures have been observed in Lake Thun and ultimately document the seismic activity of the study area. A first investigation of possibly first-order active structures is presented in the scope of this study. Recently acquired bathymetric data in Lake Thun reveal significant morphologic depressions aligning with an observed lineament on land. Furthermore, high-resolution seismic images indicate potential fault structures in Lake Thun. However, their continuation with depth has to be verified with a multichannel seismic campaign, scheduled for March 2015.