LAKE FORMATION AND CATASTROPHIC DAM BURST DURING THE LATE PLEISTOCENELAACHER SEE ERUPTION (GERMANY)

Instantaneous overloading of the Rhine River with tephra during the er uption of Laacher See Volcano c. 12900 aBP led to the formation of a m ajor dam at the bottleneck oulet of the morphological Neuwied Basin. A temporary lake formed upstream between Andernach and Koblenz, extendi ng for some 140 km(2) and rising more than 15 m above the pre-eruptive land surface. Collapse of the unstable dam prior to the final phase o f the eruption resulted in sudden drainage of the lake. Deposits laid down by the catastrophic floodwaves occur at least as far north as Bon n, more than 50 km downstream from Andernach.