Evidence of Catastrophic Geology: Case 8

"Lake Tsunamis"

Tidal waves (tsunamis) do not only occur in oceans,  Catastrophic events can occur in lakes as well that cause large wave action.  Any lake within notable topography is typically at risk of experiencing a tsunami.  Lake Geneva in Switzerland has been studied impressively and geologic evidence indicates several tsunamis have occurred during the lake's existence.

As reported in Nature Geoscience, Dr. Kremer has performed notable study of the lake and theorizes that the recorded tsunami of 563 AD which devastated the city of Geneva (several historical accounts are available that describe the event) was caused by a landslide of massive rock debris into one side of the lake, destabilizing tall underwater canyons of soft deltaic sediment (where Rhone river feeds into lake).  The huge underwater global slope stability failures created the wave action that produced 0 to 14 meter tall waves (that is 46 feet max) that devastated many of the communities along the lake shores.

An image reported in the Economist magazine is presented below.

Beds (layers) of turbidite (alluvial deposits of high velocity water) in the lake help support the theory.  4 apparent beds totaling 20 feet thick may have been formed in just 4 single day events.  20 feet of wide-scale sedimentary deposit in 4 days, not millions of years.  

The layers are roughly 10km long (6 miles long) and 5km wide.  Organic material present in the first layer was carbon dated and closely matches the 563 AD age.  The sediment at the river delta also obviously accumulates very rapidly to form the dangerous underwater canyons.  Since the lake is suspected to have formed after THE ice age, the frequency of the tidal waves is a cause for concern.  When is the next one?