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Non-Water Release Corrective Action Plan North County Recycling Center and Sanitary Landfill ® For purposes of this evaluation, seismic impacts to the landfill will use a PGA of 0.158 to be conservative and to exceed the largest predicted MCE at the site. The results of the seismic analysis are presented in Appendix A. 4.1.1 Impacts from Ground Rupture Seismically-induced ground rupture occurs when a fault moves during an earthquake. The nearest active fault is approximately 30 miles from the site. Accordingly,there is no reasonable expectation that ground rupture could occur at the landfill site because of the distance to the nearest active fault. Therefore, this is not a reasonably foreseeable impact at this 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 site is within 9.6 miles of the Camanche Reservoir, 16.3 miles from New Hogan Lake, and 18.9 miles from the Salt Spring Valley Reservoir and not within the drainages from either source of water. Accordingly, at these distances and locations, an impact from a seiche is extremely unlikely, and outside the definition of a reasonably foreseeable impact. 4.1.3 Impacts from Tsunamis A tsunami is an oceanic wave or series of waves produced by an undersea or near-shore earthquake, landslide, or volcanic eruption. The NCRCSL is located approximately 65 miles from the Pacific Ocean (San Francisco Bay) at an elevation of 110 feet above mean sea level. As a result, impact from a tsunami is considered extremely unlikely, and outside the definition of a reasonably foreseeable impact. 4.1.4 Impacts from Liquefaction and Associated Dynamic Settlement Liquefaction and dynamic settlement of soils can be caused by strong vibratory motions that occur during an earthquake resulting in a total loss of shear strength in the affected soil layer, thereby causing the soil to flow as a liquid, sometimes causing excessive settlement and sand boils at the ground surface. Both research and historical data indicate that loose, saturated, granular soils are susceptible to liquefaction and dynamic settlement, while the structure of silty clays and clays is not adversely affected by vibratory motion. Boring log data from EMCON (1987) and Kleinfelder (1986) were reviewed to evaluate subsurface conditions at the site. The majority of the foundation soils of the landfill are composed of dense, silty sand and very stiff to hard silts and clays. The SPT blowcounts as reported on the boring logs were generally greater than 30 blows per foot. The depth to the water table below the base of the landfill ranges from 100 to 120 feet. In accordance with the State of California (SCEC, 1999), if the groundwater table is not within 2013.A135 I N:\San Joaquin\North County\Non-Water Release CAP\Final Report\North County_NWCAP_Report_Final.docx July 2014,Rev.0 6