Liquefaction_Susceptibility_Map_Teton_County_Idaho

Liquefaction occurs during strong earthquake ground shaking when saturated, cohesionless earth materials lose strength due to high excess pore-water pressure. Liquefaction susceptibiliy was estimated by mapping deposits likely to contain cohesionless sediments such as loose sand, and by mapping areas subject to saturation by water. A standard methodology (ATE Classification) was used to relate deposit age, texture (grain size and sorting), and environment of deposition to liquefaction susceptibility. Average depth to the local water table was determined from soil maps and the static water level in shallow water wells. This analysis was performed at a scale of 1:50,000  in an area containing  the majority of county population and infrastructure, including the towns of Tetonia, Driggs, and Victor.  Outside of this area liquefaction susceptibility was not analyzed but is probably very low. Liquefaction susceptibility is highest adjacent to the Teton River on terraces, marshes, low gradient flood plains, and on the flood plains of some secondary streams.

Liquefaction susceptibility in Teton County, Idaho was mapped to help mitigate earthquake hazards in the area.

Liquefaction_Susceptibility_Map_Teton_County_Idaho.PDF -- digital map that can be viewed with Adobe Reader or printed.
README_Documentation_Liquefaction_Susceptibility_Map_Teton_County_Idaho.PDF -- describes methods used to prepare the map.
LQ_Teton_County_Detailed_Study_Area_SP27_Grid.txt -- text grid composed of susceptibility class, latitude, and longitude.

Polgyon positions showing liquefaction susceptibility classes are approximate and may not reflect true site conditions. This map is designed for use at 1:50,000 and is not suitable for engineering-scale work. The position of polygons was derived from soil maps, water table model constructed with well logs, and analysis of Age-Texture-Environment of deposits (see README Documentation for details).