High-Resolution Studies of Mass Transport Deposits: Outcrop Perspective for Understanding Modern Submarine Slope Failure and Associated Natural Hazards
Micro- to meso-scale outcrop studies on selected field analogues allow direct calibration and testing of geophysical interpretations performed on mass transport deposits in modern continental margins, in terms of genetic processes and sliding dynamics. This comparative approach provides important information for forecasting and mitigating submarine landslide-related geohazards. The comparison of fieldwork studies (i.e., siliciclastic, carbonate and mixed, seismic-scale Eocene-Oligocene submarine mass transport deposits of the Northern Apennines in Italy, central Pyrenees in Spain and the north-western Dinarides in Italy/Slovenia) with multibeam bathymetric, seismic and drill core data from some modern analogues (i.e., offshore of New Zealand, Japan and Svalbard in Arctic Norway) is proposed in order to upscale the outcrop observations and downscale the geophysical features. Our results show that slide mass mobility is a function of the degree of internal liquefaction/fluidization, mainly achieved at the basal sliding interval and within the slide body. This is due to undrained shearing/loading-unloading of poorly-lithified sediments, and consequent development of fluid overpressure that is able to accommodate deformations at high strain rates. Structures related to these processes are observable at all scales, and represent diagnostic criteria to recognize potentially catastrophic mass transport events.
KeywordsExhumed mass transport deposits Geophysical analogues Shear-induced liquefaction
Norwegian Hydrographic Survey provided multibeam data from Svalbard. Joshu Mountjoy supported by NIWA under Coasts and Oceans Research Programme 1 (2013/14 SCI). This work is part of the MIUR-PRIN n. 2010AZR98L_002 program.
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