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GEOSYNTEC CONsu.TAN-rs <br /> Dr. HariSharma, P.E., G.E. <br /> 22 January 2001 <br /> Page 6 <br /> to "fill" the envelope between the median and 84`h percentile response spectra in the <br /> period range from approximately 0.08 seconds to 2 seconds, all three accelerograms <br /> were scaled up. In particular, to represent the M,, 6.4 MPE, the accelerograms were <br /> scaled to a PHGA of 0.13 g rather than a median MPE PHGA of 0.09 g. To represent <br /> the MW 6.7 MCE, the accelerograms were scaled to a PHGA of 0.19 g rather than a <br /> median MCE PHGA of 0.13 g. The acceleration response spectra of the time histories <br /> selected to represent the MW 6.7 MCE event on the Great Valley blind thrust system are <br /> plotted in Figure 2. The acceleration response spectra of the time histories selected to <br /> represent the M,,6.4 MPE event on the Great Valley blind thrust system are plotted in <br /> Figure 3. <br /> The magnitude 8+ synthetic accelerogram was selected to represent the MW <br /> 7.9 MPE/MCE event on the San Andreas fault. To compensate for a duration <br /> deficiency and to "fill" the envelope between the median and 84`h percentile response <br /> spectra in the period range from approximately 0.08 seconds to 2 seconds, the <br /> Magnitude 8+ synthetic accelerogram was scaled to a PHGA of 0.10 g rather than the <br /> median MPE PHGA of 0.06 g. The acceleration response spectrum of the Magnitude 8+ <br /> synthetic accelerogram representing the MPE/MCE MW 7.9 event on the San Andreas <br /> fault system is plotted in Figure 4. <br /> CONCLUSIONS <br /> This letter report presents a seismic site exposure evaluation for the Forward <br /> Landfill in San Joaquin County, California. In performing this evaluation, seismic <br /> sources capable of generating strong ground motions at the site were evaluated based <br /> upon the best available information on regional seismicity and seismic geology. The <br /> Maximum Credible Earthquake (MCE) and Maximum Probable Earthquake (WE) <br /> moment magnitudes and site-to-source distance pairs for each of these seismic sources <br /> were established on the basis of published data. The Peak Horizontal Ground <br /> Acceleration (PHGA) and significant duration of strong ground shaking (DS) at a <br /> hypothetical bedrock outcrop at the geometric center of the site was established for each <br /> P IPRJIICA WPWOCALIF-WCIFORWARDIFOR-HAZ.DOC <br />