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- 15 - <br />Lineations visible on aerial photography indicate that the slide <br />mass is cut by a series of discontinuous linear escarpments which <br />range from a few feet up to several tens of feet high. The trends of <br />many of the photograph lineations show good correlation with known <br />fault zones. The approximate surface location of the northeastern <br />mine fault in the vicinity of the leaching plant site is shown on" <br />Fig. 2. The location of this fault at the surface is based on <br />photograph lineations and surface topography. <br />SEISMOLOGY <br />The southwestern Colorado region is in an area of relatively low <br />seismic activity. Eighty earthquakes have been recorded within <br />200 miles of the site between 1893 and 1978, see Fig. 7. The majority <br />of the earthquakes were small and resulted in no damage even near <br />their epicenter. Damage was reported from 17 earthquakes within the <br />region. A list of damaging earthquakes is shown on Table I. Modified <br />Mercalli intensities of the damaging earthquakes range from V to VIII. <br />All earthquakes with large epicenter intensities are associated with <br />the Wasatch Mountain Front in Utah and are located over 175 miles to <br />the west of the site. In addition to these large earthquakes, several <br />moderate sized earthquakes have been reported to the east of the site <br />in the vicinity of Buena Vista, Colorado; Montrose, Colorado and <br />Dulce, New Mexico. Epicenters for the 1901 Buena Vista and 1966 Dulce <br />earthquakes were over 120 miles from the site. The epicenter for the <br />1960 Montrose earthquake is located about 60 miles east of the site. <br />This is the closest earthquake to the lease which had reported damage. <br />