Question

When does liquefaction occur?

Answer 1

When the combination of pressure and temperature are high enough to change the physical state from solid to liquid.

Explanation:

Chemically, all substances have phases (solid, liquid and vapor) that are determined by the temperature and pressure of their surroundings. Geologically, this means that rock liquefaction will occur when the pressure and temperature are high enough to change it from a solid to a liquid phase. This normally occurs primarily due to pressures at depths below the earth's surface, which also may contribute to the heating processes.