Laserfiche WebLink
34 <br /> identified at the site of the proposed facility. Consequently, the possibility <br /> of ground surface fault rupture onsite is very small. However, seismic ground- <br /> shaking from offsite earthquake activity is expected to affect the site over the <br /> life of the facility. <br /> Faulting through central California is dominated by the northwest-trending <br /> San Andreas, Hayward, and Calaveras fault systems. As shown on the Fault Map of <br /> California (Jennings, 1975) , these faults, and a small fault near Antioch com- <br /> prise the faults having documented historical displacement near the site. As <br /> shown on the California fault map, the nearest active or potentially active fault <br /> to the site is a small fault near Midway, about 17 miles west of the site (Jen- <br /> nings, 1975) . However, the San Joaquin County Seismic Safety Element (1978) <br /> considers several faults in the county, nearer to the site, as active and poten- <br /> tially active. <br /> As described in the San Joaquin County Seismic Safety Element (1978) , the <br /> following faults are of concern to development of the site. <br /> o San Joaquin Fault Zone - a fault which extends from Tracy to Los Banos, <br /> paralleling Interstate 5. Geologic studies suggest activity along this <br /> fault during the Quaternary. The precise location of this fault, <br /> maximum earthquakes expected along it, or its activity are not dis- <br /> cussed in the seismic element. For this study, it is considered as <br /> potentially active. <br /> o Tracy-Stockton Fault - This fault, passing directly beneath Stockton, <br /> is known only from oil well log data. This fault is not exposed at the <br /> ground surface. Subsurface data indicate that the fault has been <br /> inactive for the last 5 million years. However, the seismic element <br /> discusses an 1881 earthquake which they say might be associated with <br /> this fault. Based on the correlations, we concur with the county <br /> seismic activity element and will consider the Tracy-Stockton fault as <br /> potentially active. <br /> o Midland Fault - Buried under Quaternary alluvium, the activity of this <br /> fault is poorly known. The seismic element credits this fault for an <br /> earthquake near Vacaville in 1892. The seismic element lists the <br /> maximum probable event for this fault at 7.0. <br /> The location of the project site with respect to local and regional faults is <br /> shown on Plate 46. <br /> 1144A/CC-34 <br /> [?—'!'McClelland <br />