Liquefaction

When soil behaves like a liquid it can lose its ability to support structures. The soil can even flow down very gentle slopes, and erupt to the ground surface to form sand boils (“sand volcanoes”). Many of these phenomena are accompanied by settlement of the ground surface, appearing as surface cracks, vertical settlement of the surface, and lateral spreads (blocks of surface material that move centimeters to meters downslope). These surface changes usually occur in uneven patterns that damage buildings, roads, and pipelines.