Liquefaction mapping with a geographic information system Monterey County, California

This thesis addresses the use of a Geographic Information System (GIS) for mapping potential liquefaction areas in Central Monterey County, California. Currently no large scale maps showing areas susceptible to liquefaction exist for this part of the county. This GIS study uses the existing digital database map of the Monterey County soils survey to combine soil units into Quaternary geologic units by geomorphic surface type then differentiates the geologic units by age to create maps of liquefaction susceptibility. The Quaternary geologic units are tabulated and the typical depth to ground water for each unit is estimated from existing ground-water maps. The units which can become water saturated are identified by liquefaction susceptibility criteria from very low to very high. These maps can be used to identify areas where liquefaction may occur. A GIS provides an effective use of existing data to produce these digital database maps.