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<br /> Given the 1ac:c of historical earthquakes, the geJ10gLC record <br />1 must be relied upon to assess the seismic potential. <br />' SEISMIC POTENT L4L BASED OV FAULT SCARPS <br /> One of the major contributions by Kirkham and P.ogers is the <br /> attention paid to carefully mapping fault scarps in the San Luis <br />' Valley. Of main concern to the Battle Mountain Gold project is the <br /> series of faults between San Pedro Mesa and the Sangre de Cristo <br /> mountains. Were it not for the Holocene scarps at the base of the <br />' range, this mountain front (see Figure 10; Kirkham and Rogers) <br /> would be classified as a Class II mountain front (modE~rate to <br />' slightly active) according to Bu11 and McFadden (1977;. This <br /> classification considers the behavior of fluvial processes across <br />1 tectonically active mountain fronts. The degree of mocmtain front <br /> sinuosity, entrenchment of alluvial fans and width of flood <br /> plains in major streams all suggest a mountain front Y.aving low <br /> tectonic activity. Whether the relatively fresh scarp<_ at the <br />' base of the range signal renewed activity, or merely a continuation <br />f <br />h <br />i <br />i <br />i <br />ibl <br />i <br />hi <br />l <br />h <br /> t <br />e to ascerta <br />r at t <br />s <br />o <br />e s <br />ugg <br />s <br />tecton <br />cs <br />s not poss <br /> time. <br /> Four sources of data provide background for assessing the <br /> age and activity of faults along the base of the Sangre de Cristo <br /> range. These data are presented in Table I and Figure 1. From <br /> Figure 1 a range of background deformation rates can be calculated <br />' to be from 0.4 mm/yr to 0.1 mm/yr. <br /> Determining earthquake magnitudes responsible for faulting <br /> near San Luis is difficult given the sparse data. Information <br />' is lacking, for example, on precisely how scarp heights were <br /> measured by Kirkham and Rogers. Scarps having ages of hundreds <br />' to thousands of years appear larger than the original scarps <br /> due to erosion and spalling at the scarp top, and deposition which <br /> conceals the scarp toe. Hence, the "typical" fault dislocation <br /> used by Kirkham and Rogers may be too large. <br />1 <br /> <br /> <br />