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FORWARD LANDFILL NON-WATER CORRECTIVE ACTION PLAN 4.0 REASONABLY FORESEEABLE NON-WATER IMPACTS This section of the NWCAP describes the potential non-water impacts to the Forward Landfill that are associated with known or reasonably foreseeable site-damaging scenarios. These scenarios have been developed in accordance with CalRecycle's BMPs for Preparing Site- Specific Non-Water Quality Corrective Action Plans. 4.1 SEISMICALLY-INDUCED IMPACTS Seismically-induced impacts are those that result from a large earthquake that occurs within a distance of engineering significance to the site, and could include one or a combination of the following: ground rupture, slope failure, dynamic settlement, liquefaction, or seiche or tsunami. In order to determine which, if any, of these seismically-induced phenomena could affect the Forward Landfill, a site-specific seismic hazard assessment was conducted to identify faults within a 100-kilometer radius of the site and to estimate the peak ground acceleration associated with the Maximum Credible Earthquake (MCE). The seismic hazard assessment was completed in 2008 as part of the geotechnical investigation to support landfill expansion (GLA, 2008), and concluded that although there are no active faults that cross the site, several faults lie within a distance of engineering significance to the site. Of these, the Great Valley 7 fault, which is located within 20 miles of the site, has the potential to produce the largest ground motions at the site. Using established, conservative ground motion attenuation relationships, a Peak Horizontal Ground Acceleration(PGA) of 0.15g was calculated for an MCE of magnitude 6.7 along this fault. The results of the seismic hazard analysis and risk assessment were used to determine the potential for seismically-induced impacts. 4.1.1 Impacts from Ground Rupture Seismically-induced ground rupture occurs when a fault moves during an earthquake. No active faults have been identified at or trending toward the site. As a result, there is no reasonable expectation that ground rupture could occur at the site. 4.1.2 Impacts from Seiches A seiche is a seismically-induced wave on a restricted water body such as a bay, harbor, lagoon, or lake. The nearest sizable surface water body is Woodward Reservoir, located approximately 17 miles east-southeast of the site. The large distance between the landfill and this reservoir suggests that an impact from a seiche is extremely unlikely, and outside the definition of a "reasonably foreseeable" impact. M:\2011-0128\NWFA REPORT.DOC% 9 Geo-Logic Associates