Final answer:
Soil and loose sediment are most prone to liquefaction, particularly when saturated and unconsolidated. This process typically happens during seismic events and can lead to significant damage to structures founded on such materials.
Step-by-step explanation:
The type of geologic material most prone to liquefaction is soil and loose sediment. Liquefaction occurs when the strength and stiffness of soil is reduced by an event like an earthquake or other sudden change in stress condition. The phenomenon mainly affects unconsolidated, saturated soils, and it happens because the water pressure in the pores of the soil increases, which causes particles to lose contact with each other, behaving more like a liquid than a solid.
Sedimentary rocks like sandstone may also be prone to liquefaction, especially when they are poorly cemented. In comparison, igneous rocks such as granite, and metamorphic rocks are generally more resistant to liquefaction due to their crystalline structure, strong interlocking of minerals, and typically lower porosity and water content.
Liquefaction can cause significant damage during seismic events, as it may lead to buildings or other structures sinking, tilting, or collapsing if they are founded on or contain materials susceptible to this process.