Look Up the Local Soil Type at Your Site Based on known velocites for rock units, we have assigned soil-types to the rocks in the Bay Area. You can zoom in on any local site in the San Francisco Bay Area and determine the soil type that has been assigned there. Before going to the regional index map, please bear in mind some caveats . Surface geology provides only a rough estimate of the site effect. Map boundaries are accurate only to within about 50 meters.
Soft soils tend to overlie stiffer soils and bedrock.
It has been assigned a soil-type of C, based on its average velocity.