Ground liquefaction is a phenomenon that can cause major damage to buildings when it occurs during earthquakes where water-saturated soil loses its strength and stiffness, causing it to behave like a liquid. The key points are:
Soil liquefaction occurs when earthquake shaking disrupts the soil structure, causing the water pressure between soil particles to rise dramatically. This reduces the effective stress (shear strength) of the soil, allowing the particles to move freely and the soil to flow like a liquid.
The effects of soil liquefaction can be extremely damaging. Buildings and infrastructure can experience sudden loss of support, leading to drastic and irregular settlement, structural damage, and failure of underground utilities. Sloping ground and areas near water bodies may experience lateral spreading and sliding on the liquefied soil layer.