Laserfiche WebLink
J. H. KLEINFELDER & ASSOCIATES <br />1� <br />File No. S-1008-35 <br />May 17, 1985 <br />Page 5 <br />SITE GEOLOGY <br />The site is underlain by consolidated alluvial deposits of the Laguna Formation <br />overlying the Mehrten Formation. The Laguna Formation consists of consolidated gravels, <br />sandstones, and siltstones . The slightly older Mehrten Formation generally consists of grey <br />to tan -brown sandstone and siltstone, with conglomerate layers and claystone or mudstone. <br />The formations are generally overlain by residual soil or recent alluvial deposits except <br />where exposed by the current landfill operations. <br />FAULTS AND SEISMICITY <br />The major faults which have historically produced earthquakes of greatest magnitude <br />in Central California are the Calaveras, Hayward and San Andreas faults in the Coast <br />Ranges; the Midland and Green Valley faults on the west side of the Great Valley; and the <br />Sierra Nevada and Owens Valley faults east of the Sierra crest. Local faults include <br />numerous small shear zones and two major fault zones, the Bear Mountains and Melones, <br />which make up the Foothills fault system. Plate IV of this report indicates the position of <br />the Foothill Landfill site in relation to the major fault zones of Central California. Also <br />shown on Plate IV are earthquake epicenters with recorded Richter magnitudes of 5.0 or <br />