Lake - Tsunamis

In several lakes, subaquatic delta collapses represent a major cause for tsunamis (e.g. Rhone delta in 563 AD in Lake Geneva; Muota delta in 1687 in Lake Lucerne; Aare Delta in 1996 AD in Lake Brienz). Although from the sediment record, these tsunamigenic delta collapses occur at recurrence rates of >1000 years, similar small-scale non-tsunamigenic delta failures are documented in several recent studies (Talling et al., 2015, and references therein). Using repeated multibeam bathymetry surveys of deltas and sediment cores, we address the following questions:

• How often do these delta collapses occur?
• Can external triggers be associated to these collapses?
• Can we distinguish the deposits of these collapses from other turbidites (floods)?

University of Berne, Departement of Quaternary Geology and Paleoclimatology

Flavio Anselmetti

Katrina Kremer