EARTHQUAKE_LIQUEFACTION_POTENTIAL_MM81_IN is a polygon shapefile that shows highly generalized categories (low, moderate, and high) of liquefaction potential, based on soil classes of the National Earthquake Hazards Reduction Program (NEHRP). Low liquefaction potential includes NEHRP Soil Class B (consisting of rock: sandstone, limestone, shale). Moderate liquefaction potential includes NEHRP Soil Class C (hard or stiff soil, or gravel) and part of NEHRP Soil Class D (stiff soil, stiff clay, and some gravel). High liquefaction potential includes parts of NEHRP Soil Class D (stiff soil, stiff clay, and some gravel), and all of NEHRP Soil Class E (soft soil and soft to medium clay) and F (lake and river deposits of sand and mud). The following is excerpted from Indiana Geological Survey Miscellaneous Map 81: "Liquefaction is a common ground-failure hazard associated with earthquakes. It is defined as the sudden and temporary loss of strength of a water-saturated sediment. This could result in the structural failure of buildings, bridges, and other structures."