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Soil Investigations for Data Collection in the Delta Initial Study/Proposed Mitigated Negative Declaration 147 seismic events. The extent of ground shaking associated with an earthquake depends on the magnitude and intensity of the earthquake, distance from the epicenter, and local geologic conditions. Major active faults in the region that could cause ground shaking at the Impact Areas include Antioch, Calaveras, Cleveland Hills, Concord, Greenville-Marsh Creek, Hayward, San Andreas, San Joaquin and Sierra Nevada Faults. The closest active fault is the Greenville-Marsh Creek Fault, which is located 9 miles southwest of the most southern Impact Area. The most recent seismic event occurred in January of 1980 when two earthquakes of Richter magnitude 5.5 and 5.8 occurred along this fault (McJunkin and Ragsdale 1980). The Impact Areas are small, work would be temporary, and not anticipated to cause enough ground disturbance to result in strong seismic shaking. While there would be a less than significant impact, implementation of Mitigation Measures MM AES-1 and AGR-1 would further avoid, minimize and/or reduce the potential for impacts.. iii) Seismic-related ground failure, including liquefaction? No Impact. Liquefaction is the transformation of saturated, loose, fine-grained sediment to a fluid-like state because of earthquake shaking or other rapid loading. Soils most susceptible to liquefaction are loose to medium dense, saturated sands, silty sands, sandy silts, non-plastic silts and gravels with poor drainage, or those capped by or containing seams of impermeable sediment. According to the USGS Susceptibility Map of the San Francisco Bay Area, the proposed activities are in regions designated as a low to moderate risk of liquefaction (ABAG 2018, CDC 2010b). However, due to recent earthquake activity in 1980 on the Greenville- Marsh Creek Fault which resulted in no liquefaction, and the limited footprint of each soil exploration, ground failure including liquefaction is not expected to occur. While there would be no impact, implementation of Mitigation Measures MM AES-1 and AGR-1 would further avoid, minimize and/or reduce the potential for impacts. iv) Landslides? No impact. Seismically induced landslides and other slope failures are common occurrences during or soon after earthquakes in areas with significant ground slopes. Geotechnical investigation record information did not identify landslides as a potential hazard in the Impact Areas. The Impact Areas are not located in areas susceptible to landslide risk and there are no mapped areas of landslide deposits larger than 200 feet (CDC 2015b). The criteria used to delineate the relative hazard areas included the nature of the geologic materials underlying the surface, the steepness of slopes, the presence or absence of visible slope failures, and the presence or absence of active forces that could cause failures. The Impact Areas are in relatively flat areas, which do not have a potential for landslide. Therefore, the Proposed Project would have no impact. b) Would the project result in substantial soil erosion or the loss of topsoil?