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1997 U.B.C.DESCRIPTION FACTOR <br />Table 16-J Soil Profile Type So <br />Figure 16-2 Seismic Zone 4 <br />Table 16-I Seismic Zone Factor Z 0.40 <br />Table 16-Q Seismic Coefficient, Ca 0.49 <br />Table 16-R Seismic Coefficient, Cv 0.86 <br />Table 16-S Near Source Factor, Na 1.1 <br />Table 16-T Near Source Factor, Nv 1.3 <br />Table 16-U Seismic Source Type B <br />Nearest Fault San Joaquin Hills 3.9 Km <br />GROUNDWATER <br />The subject site is located on a portion of the California Division of Mines and Geology <br />(CDMG) 7.5 Minute Newport Beach Quadrangle Seismic Hazard Zones Map showing <br />potential for liquefaction. Groundwater was encountered at a depth of approximately 17.5 <br />to 21.5 feet below the existing ground surface. However, historic high groundwater <br />elevation was reported to be 5 feet below the existing surface. <br />LIQUEFACTION POTENTIAL <br />Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake- <br />induced ground motion, create excess pore pressures in relatively cohesionless soils. <br />These soils may thereby acquire a high degree of mobility, which can lead to lateral <br />movement, sliding, consolidation and settlement of loose sediments, sand boils and other <br />damaging deformations. This phenomenon occurs only below the water table; but after <br />liquefaction has developed, it can propagate upward into overlying non-saturated soil, as <br />excess pore water dissipates. <br />One of the primary factors controlling the potential for liquefaction is depth to groundwater. <br />Typically, liquefaction has a low potential where groundwater is greater than 40 feet deep <br />and is virtually unknown below 60 feet. <br />Liquefaction analyses were performed using the computer program "LIQUEFY 2" version <br />1.50 developed by Thomas F. Blake (see Appendix E). The program was written to <br />include the procedure recommended by the National Center for Earthquake Engineering <br />Research (NCEER, 1997). Liquefaction potential analysis and estimate of seismically <br />induced settlement were performed for the design earthquake events that have 10 percent <br />probability of exceedance in 50 years (475 years of return period), as per CDMG Chart <br />(Seismic Hazard Zone Report for the Anaheim & Newport Beach 7.5 Minute Quadrangles, <br />Pacific Development Group <br />1307 West Sunflower Avenue, Santa Ana <br />File:\server\andree\4900\4976al.foundshopctr GeoSoils, Inc. <br />W.O. 4976-Al-OC <br />November 2,2005 <br />Page 5