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Seismically-triggered seafloor landslides are common in areas of weak geologic materials such as rapidly deposited sediment or fractured rock.Seafloor slopes are subject o the same type of mass failures as are found on land.Submarine liquefaction failures can occur on nearly-flat continental shelves,whereas coherent seismic-slope failures tend to occur on the shelf-break and continental slopes of active-margins.Some slope failures can involve enormous amounts of material and can move great distances.Displacement of the seafloor can occur across a broad spectrum of environmental and geotechnical conditions.When the high-strain dynamic yield strength of the seafloor material exceeds the slope gravitational shear stress,failure only occurs during inertial loading.If the downslope component of shear stress exceeds the yield strength of the ocean floor,movement along one or several sliding surfaces will occur until stability can be re-established.Stability is returned when excess pore-water pressures dissipate,the landslide mass thins,the slope becomes less steep,or the material yield strength rises,again,above the slope gravitational shear stress.The potential for seafloor slopes to transform from coherent masses into disintegrative landslides that flow long distances is related to the disequilibrium between seafloor high strain-shear strength and the slope-induced stresses.Under these conditions,a coherent mass can completely disintegrate into a flow of low or high speed,destroying the internal structure of the sliding mass.