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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />This fault has not been designated as potentially active in the publication "Earthquake <br />Potential in Colorado", 1981 by Kirkham and Rodgers, In this publication, the closest <br />potentially active fault to the project area is the north-south trending Laramie River <br />Forest, located approximately 12 miles to the west, This fault is reported to have a <br />length of 43 miles. to have offset late Tertiary age rocks, and to be overlain by <br />Quaternary age sediments. A second unnamed fault is located a similar distance north <br />of the site, This fault is east-west trending In the vicinity of E1khorn Creek and Lone <br />Pine Creek. This fault has a reported length of 6 miles, to have offset Tertiary age <br />rocks, and to be overlain by Holocene age sediments. <br /> <br />5.3.1.3 Overburden <br /> <br />The above mentioned geologic map indicates the valley in which the reservoir is located <br />contains glacial deposits of the Pinedale and Bull Lake Glaciations. The thicknesses of <br />these deposits are not known, Based on geomorphic evidence, it is estimated that the <br />thickness of overburden deposits may be on the order to 150 to 200 feet. These <br />deposits consist of glacial outwash, which includes interbedded sand, gravel, and <br />occasional cobbles with beds of fine sand, silt, and clay, Based on exposures near the <br />dam outlet works and the material encountered in the borings, the upper approximately <br />40 feet of outwash is primarily sand and gravel with occasional cobbles, In exposures <br />near the Inlet to the reservoir, this upper outwash is stratified in 1 to 4-foot-thick beds; <br />some contain cross-bedding indicative of braided channel fills and bars. Below this <br />level, the outwash Is generally finer grained. An interbedded layer of silt and fine sand <br />about 10 feet thick was observed In the outwash near the dam outlet works, <br /> <br />Ground and lateral moraines mande most of the bedrock on the valley slope along the <br />south side of the reservoir. The type of moraine is distinguished by the method of <br />deposition. The lateral moraine Is deposited along the edge of the Ice sheet which the <br />typically thinner ground moraine is deposited beneath the ice sheet. The moraines <br />generally consist of poorly sorted silt to boulder-sized material. Boulders range up to <br />10 feet in size, Several relatively small outcrops of precambrian rock were observed in <br />the moraine, <br /> <br />5-8 <br />