Plots of water content (omega ) and Atterberg liquid limits (omega (sub L) ) 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 omega can be higher or approximately equal to omega (sub L) (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 omega (sub L) ) of small, only fine-grained homogenized samples, if part of the dislocated material is carried unchanged as lumps of mud by a liquefied matrix, omega and omega (sub L) 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 omega to values lower than the plastic limit, omega (sub p) , and completely alters all the mass physical properties.--Modified journal abstract.