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1Nit, I[I 4: Ga•ove. crewel• Prcvjoc6: L[ou%�:P< r I lamp ! TJ NI(io Qus Qrajee.E• �ccmbzc: 1-PGu02.0:?. MaV ?A, 2007 Test hole logs show subsurface conditions at the date and location indicated and it is not warranted that they are representative of subsurface conditions at other locations and times. Groundwater was encountered in boring B1 at a depth of approximately 8 feet below the existing ground surface at the time the boring was drilled. The boring was not allowed to stay open for an extended period of time; consequently, the ground water depth should be considered approximate. Groundwater conditions in the future could change due to rainfall, construction activities, irrigation, or other factors. The evaluation of these factors is beyond the scope of this study. A detailed analysis of earthquake induced liquefaction for the proposed site was completed for the purpose of determining the potential of liquefaction and any associated induced settlement, Liquefaction is a loss of strength in soil when a cyclic stress, such as that caused by an earthquake, is subjected to typical soils, such as loose saturated sands and silts. A cyclic stress subjected to these soils may cause them to density which results in excessive pore pressures causing the soil to act as a liquid. Factors that /nayeffect the likelihood of liquefaction include the age and density of soils, recent- depths to subsurface water of 8 feet, as indicated, and the potential ground acceleration from a seismic event. Prior to providing specific recommendations for construction of the booster pump station, the susceptibility of the site to liquefaction needs to be addressed. The following describes the results of our liquefaction analysis for the site. The result s of the dynamic "blow count" Vesting performed during the drilling of a 41.5 foot deep boring have been used in our liquefaction analysis, Blow counts were Yaken approximately every 5 feet and a liquefaction analysis of each distinct stratum has been performed. Our analysis of the potential for liquefaction at the site was performed using two methods (both are based on blow count result values obtained during drilling activities). The first, and probably the most commonly used method, is that proposed by the National Center for Earthquake Engineering Research (NCEER)4, This method results in a calculated factor of safety against liquefaction. The second method is a newer method proposed by R. B. Seed and result in a calculated probability of liquefactions. 4 Youd Les/ie T., Idrlss, Izzat PA, Proceedings of the NCEE2 Workshop on Evaluation of / iqueFact/on Resistance of Soils, Technical Report NCEE2-97-0022, December 31, 1997 s Seed, R:B., RecenfAdvances in SoU Llc/uerMUU11 Fnglneering and Seismic 5/fe Resparse Eva/uatlon Proceedings of NEIL O. ANDERSON AND ASSOCIATES 902 Indust? to/ May • l.od7, CA 9s �,P �2007WI O. Anderson & Associates, roc.