What type of soil is most susceptible to liquefaction during an earthquake?

Sandy soils are the most susceptible to liquefaction during an earthquake due to their physical characteristics and the way they respond to seismic forces. Liquefaction occurs when saturated, loose, granular material, such as sand, temporarily loses its strength and stiffness in response to applied stress, like that from seismic shaking.

When an earthquake strikes, the shaking can cause the water pressure within the spaces between sand grains to increase. In sandy soils, this can lead to a situation where the grains of sand lose their contact with one another, effectively behaving more like a liquid than a solid. This phenomenon is particularly pronounced in loose, unconsolidated sands that are saturated with water.

Other types of soils, such as clay or rocky soils, do not exhibit the same propensity for liquefaction. Clay soils, with their fine particles and cohesive nature, tend to hold together better under stress, while rocky soils typically have a greater density and strength, making them more stable during seismic activity. Loamy soils, being a mixture of sand, silt, and clay, also do not typically experience liquefaction to the same extent as sandy soils.