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San Joaquin County Environmental Checklist seismic sources in the project vicinity(International Conference of Building Officials 1997). The landfill property is located in UBC Seismic Hazard Zone 3. The Zone 3 designation indicates that earthquakes in the region have the potential to make standing difficult and cause stucco and some masonry walls to fall. Structures must be designed to meet the regulations and standards associated with Zone 3 hazards. One pre-Quaternary fault is located within an approximately 20-mile radius. The Stockton fault runs east to west,south of the landfill property;however,this fault is concealed by younger rocks and its continuation or existence is not certain (Walker,et al. 1994). This fault is not located within Alquist-Priolo Special Studies Zones(Hart and Bryant 1997). The nearest active faults are the Green Valley,Concord,Clayton,Marsh Creek, and Greenville Faults, approximately 50-60 miles to the west(Walker et al. 1994). The Bear Mountains fault zone, one of several fault zones in the Foothills fault system,is approximately 20 miles east. The Bear Mountains fault zone is a pre-Quaternary fault zone,as are almost all the faults associated with the Foothills fault system. Based on a probabilistic seismic hazard map that depicts the peak horizontal ground acceleration values exceeded at a 10%probability in 50 years(California Geological Survey 2003;Cao et al. 2003),the probabilistic peak horizontal ground acceleration value for the area is 0.1 to 0.2 g. This indicates that the ground-shaking hazard in the area is low. Poorly consolidated,water-saturated fine sands and silts located within 50 feet of the surface are typically considered to be the most susceptible to liquefaction. Soils and sediments that are not water saturated and consist of coarser or finer materials are generally less susceptible to liquefaction(California Division of Mines and Geology 1997). Depth to groundwater in the project vicinity is greater than 6 feet,and the area is partially underlain by sandy loam(see below). However,because the ground-shaking hazard in the area is low,the susceptibility of soils and sediments to liquefaction is also low. The soil map units as described by the Soil Survey of San Joaquin County are Montpellier-Cometa complex, 5-8%slopes; Valdez silt loam, deep; Rocklin sandy loam, 2-5% slopes; and San Joaquin sandy loam, 2-5% slopes (McElhiney 1992). These soil map units are characterized by sandy loam,a relatively low depth to the seasonal high water table, very slow to moderate permeability, slight to moderate erosion hazard, slow to medium runoff, and generally low to moderate shrink-swell potential. However, most of the project area is an operational landfill, and native soils have been disturbed. Artificial fill, most likely resting on top of the native soils,is widespread. Therefore,no firm conclusions can be drawn about severity of erosion hazard or shrink-swell potential. Geologic material in the area is dominated by the sand,silt,and gravel of the Quaternary Turlock Lake Formation(Wagner et al. 1987). Also present is the Quaternary Riverbank Formation,which consists of alluvium(Wagner et al. 1987). However,because this area has been disturbed,local geologic maps do not fully depict in situ conditions. Imported artificial fill,most likely resting on top of the described units,is present throughout the area. Notice of Preparation for the June 2006 North County Recycling Center and Sanitary Landfill 2-39 Permit Revision J8S 06307.06