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Hacienda Mixed Use Rezoning Initial Study Business Park before its development' to analyze whether the project sites are located in areas of seismic activity. The three sites are located in the vicinity of the known Mt. Diablo Fault, although they are not in any landslide zone or in an Alquist Priolo Special Study Zone (Figures 5 -1, 5 -2, and 5 -5 of the Public Safety Element). The sites axe in an area designated as "Severe to Violent" for relative intensity of ground shaking by the California Geological Survey and are listed in a liquefaction zone in the California Geological Survey Seismic Hazards Zonation Program (Figures 5 -3 and 5 -4 of the Public Safety Element of the General Plan). Regarding expansive soils, the three sites have the potential to contain such soils. Significance Criteria The impact questions above constitute the significance criteria for this environmental topic. Discussion of Checklist Items Less- than Significant Impacts. The project vicinity has a relatively high susceptibility to seismic shaking. The greatest seismic risks for the area are from a large earthquake on the Calaveras fault on the Pleasanton Ridge flank, and to a slightly lesser extent, large magnitude earthquakes on the more distant Calaveras fault segments, as well as on the Calaveras, Concord, Greenville, Hayward, or San Andreas faults. Such events could cause extensive damage to structures and infrastructure. Because the site vicinity is located in an area susceptible to liquefaction and expansive soils, the potential exists for development due to the proposed zoning change to be subject to these hazards. Thus the project sponsor of development of the site would have to submit geotechnical or soils studies at the time development is proposed on any of the three project sites, if required to update the existing analysis conducted in 1981. The City of Pleasanton requires all development projects to conform to the most current California Building Code as amended by Pkasanton Municipal Code Chapter 20.08: Building Code. Thus the project sponsor would be required to design and build all structures to withstand predicted peak accelerations of a maximum credible earthquake. Development of the three project sites due to the proposed zone change would require an NPDES permit as the proposed grading would involve more than 1 acre of ground disturbance. Implementation of the required NPDES permit would reduce this impact to a less than- significant level for soil erosion issues. No Impact. The Alquist -Priolo map for the project vicinity shows no fault trace or Alquist -Priolo special studies zone on or adjacent to any of the three project sites. The project area is located about 1 /2 mile south of the Mount Diablo Fault and approximately 2 miles east of the Calaveras Fault. Therefore fault rupture would not be expected to impact the project. The sites are generally level with no hills located nearby. Therefore, landsliding in the project vicinity would be unlikely. Sanitary sewers would serve the project vicinity and development resulting from the proposed zoning change would not involve continued or proposed used of septic systems. r Wahler Associates, Geotechnical Engineer, `Preliminary Geotechnical Investigation, Hacienda Business Park, Pleasanton, California," June 1981. Draft, Subject to Revision 14 8/31/2009