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<br />Landslides <br /> <br />Landslides visited in the Bear Creek area have caused cracking <br />and settlement near their heads and bulging near their toes that <br />may pose a much greater threat to people and animals traversing <br />the area than do subsidence cracks. Cracks were observed in the <br />landslide areas that were as much as 2 ft wide, many feet deep, <br />and offset the ground surface as much as 10 ft. <br />The landslide area south of Somerset was visited on Sept. 10. <br />Numerous slides and flows were observed in surficial material and <br />shallow bedrock above, below, and within the massive sandstones <br />that are located about 1000 ft above the North Fork of the <br />Gunnison River. These sandstones mark the stratigraphic boundary <br />between the Coal Bearing Member and the Barren Member of the <br />Mesaverde Formation. Most of the landslide activity has occurred <br />since 1980, and probably occurred during the very wet years of <br />1984 and 1985. <br />After extensive examination, no evidence was found to indicate <br />that the massive sandstones were moving in a deep-seated manner. <br />Only slabbing and toppling failure along joints near the surface <br />were observed. The apparent cracks that I observed in 1982 <br />either have filled in and now look like trails or were caused by <br />slabbing. Considerably more slides, flows, slabbing, and topples <br />probably will occur in currently impacted areas and other nearby <br />areas during extended wet periods, because of increased <br />permeability and instability caused by the existing landslide <br />activity. <br />Sincerely yours, <br />C. Richard Dunrud <br />Engineering Geologist <br />24568 Giant Gulch Road <br />Evergreen, CO 80439 <br />