In geology, liquefaction refers primarily to soil liquefaction.
Physics and chemistry
In physics and chemistry, Liquefaction, sometimes liquification, refers to any process which either generates a liquid from a solid or a gas, or generates a non-liquid phase which behaves in accordance with fluid dynamics. 
It can refer to:
In biology, liquefaction refers to a liquid state of decomposed tissue.
- Liquefactive necrosis, this condition in a living organism.
- Putrefaction, a stage in decomposition where liquefaction happens.