RT Journal Article
SR Electronic
T1 Morphology and spatio-temporal distribution of lacustrine mass-transport deposits in Wörthersee, Eastern Alps, Austria
JF Geological Society, London, Special Publications
JO Geological Society, London, Special Publications
FD Geological Society of London
SP 235
OP 254
DO 10.1144/SP500-2019-179
VO 500
IS 1
A1 Daxer, Christoph
A1 Sammartini, Maddalena
A1 Molenaar, Ariana
A1 Piechl, Thomas
A1 Strasser, Michael
A1 Moernaut, Jasper
YR 2020
UL http://sp.lyellcollection.org/content/500/1/235.abstract
AB In lakes, landslides can be studied in high resolution due to their accessibility and limited size. Here, we investigate mass-transport deposits in glacigenic Wörthersee (Eastern European Alps) by integration of seismic, sediment core and multibeam bathymetric data. Two outstanding landslide events were revealed: the first occurred in the Late Glacial, leading to multiple deposits of up to 15 m thickness; they consist of sandy turbidites and mudclast conglomerates, which are overlain by a 2.5 m thick megaturbidite. The extensive, likely earthquake-triggered failure linked to this event was preconditioned by rapid sedimentation of fine-grained glaciolacustrine sediments and associated build-up of excess pore pressure. The second event was presumably triggered by a major earthquake (Mw≈7) in AD 1348 and comprises a mass-transport complex and several landslides, which led to a c. 30 cm thick turbidite. In total, 62 landslides are imaged in the multibeam map, 6 of which are most likely human-induced. Some of these show horseshoe-type compressional ridges and frontal breaching, whereas others exhibit an extensive zone of rafted blocks. We attribute these morphological differences to four main factors: (1) slope gradient and changes therein; (2) preconditioning of the impacted zone; (3) volume of remobilized sediment; and (4) type of impactor.