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603284-001 <br />Many lessons learned about the response of certain types of structures to <br />a seismic event from the 1933 earthquake resulted in the formulation of <br />building codes and the regulation of building practices (Barrows, 1974). <br />Recorded seismicity is shown in relation to the project site on Figure 7, <br />Historical Seismicity Map. <br />3.1.3 Seismicitv <br />The site is located within a seismically active region, as is all of Southern <br />California. We have performed a site-specific evaluation of the peak <br />ground accelerations associated with the event having a 2 percent <br />probability of being exceeded in 50 years and the maximum magnitude <br />event on the controlling fault system.For these probabilistic and <br />deterministic analyses, we utilized the earthquake ground motion <br />estimation software developed by RISK Engineering (EZ-FRISK 7.23). <br />Next Generation Attenuation (NGA) relationships of Boore-Atkinson <br />(2008), Campbell-Bozorgnia (2007), and Chiou-Youngs (2007) were <br />considered in the analysis along with an average shear wave velocity for <br />the upper 100 feet (Vs30) of 250 m/s and a depth to rock with a shear <br />wave velocity of 2,500 m/s (Z2.5) of 3 km. Based on our site-specific <br />ground motion evaluation, the results of the analyses suggest that the site- <br />specific design Peak Horizontal Ground Acceleration (PHGA) is <br />approximately 0.38g based on the site-specific Maximum Considered <br />Earthquake (MCE) PHGA of 0.57g. The ground motions were determined <br />using the site-specific criteria per the 2010 CBC. Details and results of <br />our analysis are included in Appendix D. <br />3.2 Secondarv Seismic Hazards <br />In general, secondary seismic hazards for sites in the region could include soil <br />liquefaction, seismically-induced settlement, lateral spreading, landsliding, <br />seiches and tsunamis.These potential secondary seismic hazards are <br />discussed below. <br />3.2.1 Liquefaction <br />Liquefaction and dynamic settlement of soils can be caused by strong <br />ground motion due to earthquakes. Research and historical data indicate <br />that loose, saturated granular soils are most susceptible to liquefaction. <br />-12- <br />Leighton