Fig. 4

a The suggested scenario of the mass flow dynamics, an expanded version of Schnellmann (2004). The overall horizontal length is around 200 m. A: The material of the slide is considered as a liquid, scouring semi-pelagic sediments at the impact zone and continues to flow on the lake–bottom, producing contortites or gets partly homogenized as 1996 in Lake Brienz. A small part of the mass is ejected into suspension. The horizontal pressure causes the seabed to bulge. B: In the final phase, the eroded depression is filled or partly filled. b “Scour hole in plunge pool due to dynamic impact of trajectory jet” (from Hager, 1995, p. 143). The shown energy dissipater illustrates the forces of an internal hydraulic jump of a slide, which disintegrates its own structure and also the structure of the precedingly deposited slide material. A mudclast–conglomerate (debrite) results and large parts of the material are injected into suspension