Deep-reaching liquefaction potential of marine slope sediments as a prerequisite for gravity mass flows? (results from the DSDP)

Author(s): Einsele, Gerhard
Author Affiliation(s): Primary:
Univ. Tübingen, Geol. Inst., Tubingen, Federal Republic of Germany
Volume Title: Marine Geology
Source: Marine Geology, 91(4), p.267-279. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 56 refs.; illus. incl. 1 table
Summary: Plots of water content (ω) and Atterberg liquid limits (ωL) versus depth, coupled with measurements from young submarine mass flows, support the concept that many fine-grained, but low-cohesive slope sediments are susceptible to liquefaction and can, as a result of dynamic loading (earthquakes and storm waves), be transformed into mud flows without the uptake of additional water. The in-situ water content ω can be higher or approximately equal to ωL (boundary) between the plastic and liquid state of a soil) usually in the uppermost few meters, but frequently also tens or even some hundreds of meters below the sea floor. Such a substantial liquefaction potential is particularly common in sediments rich in silt-size biogenic particles and in regions of high sedimentation rates, causing underconsolidation. The average "field liquid limit" of the total mass flow can be even lower than ωL) of small, only fine-grained homogenized samples, if part of the dislocated material is carried unchanged as lumps of mud by a liquefied matrix, ω and ωL often decrease in a similar way versus depth in sediments rich in microfossils due to the onset of slight chemical diagenesis with increasing burial depth. In spite of compaction, a high liquefaction potential may be maintained, until finally substantial lithification reduces ω to values lower than the plastic limit, ωp, and completely alters all the mass physical properties. Modified journal abstract.
Year of Publication: 1990
Research Program: DSDP Deep Sea Drilling Project
Key Words: 07 Marine Geology and Oceanography; 30 Engineering Geology; Atterberg limits; Deep Sea Drilling Project; Earthquakes; Geologic hazards; Liquefaction; Liquefaction potential; Marine environment; Marine sediments; Mass movements; Mechanical properties; Plasticity; Pore water; Sedimentation; Sediments; Slope environment; Soil mechanics; Storms; Submarine environment; Transport
Record ID: 1990034912
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.

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