Additional mapping is subject to the availability of state and federal funding. Second, vegetative cover is not incorporated into the following tables because very little research has been conducted quantifying its effect. When the ground liquefies, sandy materials which are saturated with water can behave like a liquid, instead of like solid ground. In essence, the sand grains momentarily behave like a liquid. The ground needs to be shaken strongly for liquefaction to occur, and this shaking can occur as a result of an earthquake.
Liquefaction can cause ground displacement and ground failure.
In areas farther from the earthquake fault source, a material that has high liquefaction susceptibility may liquefy, but an adjacent material of moderate susceptibility may not. Liquefaction in areas shaken less than MMI VII, or in areas mapped as having a low to very low liquefaction susceptibility, is a statistical possibility, but it is not likely. The following maps show liquefaction hazard in various earthquake scenarios in three simplified categories, graphically shown below. As part of that effort, additional data on the shaking required for liquefaction to take place was collected. Click here for more information on liquefaction.