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Sliding of outrunner blocks from submarine landslides
Author(s) -
De Blasio Fabio Vittorio,
Engvik Lars Enok,
Elverhøi Anders
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl025165
Subject(s) - geology , submarine landslide , landslide , submarine , block (permutation group theory) , lubrication , seabed , lift (data mining) , debris flow , flow (mathematics) , debris , geotechnical engineering , track (disk drive) , mechanics , seismology , geometry , computer science , physics , engineering , oceanography , mathematics , mechanical engineering , data mining
Outrunner blocks are nearly intact pieces of debris that detach from a slowing‐down submarine landslide and flow ahead of the front. Data gathered from different sliding areas highlight some properties of outrunner blocks and in particular their inordinate mobility reflected in runouts of up to 25 kilometres, even on very gentle slopes. Blocks may produce an erosion glide track on the sea floor few centimetres to several metres deep, which in some cases exhibits regularly spaced grooves along the flow direction. Understanding the dynamics of outrunner blocks may shed light on the flow and lubrication of submarine landslides. We develop a simple hydrodynamic model of a rigid block interacting with ambient water and subject to lubrication with the sea floor, and calculate numerically the equation of motion for the block. We find that as a consequence of lift forces and water lubrication, the block may reach long runouts, in agreement with data. When the block is moving at high speed, we find an oscillating solution to the equations of motion which could explain the creation of dashed grooves.