The term liquefaction has actually been used to describe a number of related phenomena. Because the phenomena can have similar effects, it can be difficult to distinguish between them. The mechanisms causing them, however, are different. Flow Liquefaction Flow liquefaction is a phenomenon in which the static equilibrium is destroyed by static or dynamic loads in a soil deposit with low residual strength.
Residual strength is the strength of a liquefied soil.
Static loading, for example, can be applied by new buildings on a slope that exert additional forces on the soil beneath the foundations. Earthquakes, blasting, and pile driving are all example of dynamic loads that could trigger flow liquefaction. Once triggered, the strength of a soil susceptible to flow liquefaction is no longer sufficient to withstand the static stresses that were acting on the soil before the disturbance. An analogy can be seen in the picture above, where the static stability of a ski jumper in the starting gate is disturbed when the jumper pushes himself from the start seat. After this relatively small disturbance, the static driving force caused by gravity, being greater than the frictional resisting force between the ski and snow, causes the skier to accelerate down the ramp.