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2.0 GEOTECHNICAL CONDITIONS <br />2.1 Regional and Local Geology <br />The subject site is located in Santa Ana within the Peninsular Ranges geomorphic province of <br />southern California which is characterized by northwest trending elongated mountain ranges and <br />valleys that are truncated by the Transverse Ranges Geomorphic Province to the north and extend <br />south into Baja California. The site lies within a valley area near the western flank of the Santa Ana <br />Mountains and is underlain by flat -lying basin sediments and Holocene or modern fluvial deposits. <br />The site lies on quaternary younger alluvium which consist of silty sand, sand and clays. <br />2.2 Site -Specific Geology <br />The subject site is composed of existing fills placed as a part of the previous site development underlain <br />by quaternary younger alluvium. A detailed description is as follows: <br />Z Z I Quaternary Alluvium (Oal) <br />Quaternary alluvium consisted of reddish -brown sandy clays, clayey sands, sandy silts and <br />silty clays and were found to be damp and were soft to stiff and/or loose to dense to the <br />maximum explored depth of approximately 51.5 feet. <br />2.3 Geologic Structure <br />The site is composed of flat -lying quaternary younger alluvium. The quaternary younger alluvium is <br />interpreted as generally massive with some poorly defined, gradational, lithologic changes between <br />soil types. <br />2.4 Landslides <br />There are no slopes within the vicinity of the site; therefore, there is no landslide hazard. <br />2.5 Groundwater <br />No groundwater was encountered in our geotechnical borings to a depth of 51.5 feet, or the previous <br />geotechnical borings by others to depths of 26 feet. Historic high groundwater is considered at a depth <br />greater than 40 feet below the existing site grades per the Seismic Hazard Zone Report for the Tustin <br />Quadrangle (SHZR 012, 1998). As such, groundwater is not anticipated to pose problems during site <br />development. <br />Project i y ouncil 18 — 819 1 3 , 2021 <br />