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' <br /> c) At approximately 80,000 years ago (pre-Pinedsle) <br />' a single fault rupture of 1.2 m occurred. <br /> d) At approximately 10,000 to 14,000 years ago a single <br />' fault rupture of 1.4 m occurred. <br />i <br />th <br />M <br />C <br />l <br />i <br />i <br />l f <br />Vi11 <br /> n est <br />c <br />a <br />p <br />mates a recurrence <br />nterva <br />or <br />e <br />a <br /> Grove fault to be from 60,000 to 100,000 years. Assuming a <br />' 10 km fault length, a 12 km down dip rupture and a shear <br /> modulus of 3.3X1011 dyne.cm-2, an earthquake of approximately <br /> ML= 6.4 is capable of occurring on the Vi11a Grove fault. <br /> Sangre de Cristo Fault Zone <br /> McCalpin divided the Sangre de Cristo fault zone into <br />' three segments based on overall fault zone strike. He further <br /> subdivided the zone based on tectonic considerations. It seems <br /> reasonable for the purposes of this study to segment the Sangre <br /> de Cristo fault into characteristic single event rupture lengths. <br /> Such a subdivision results in two major segments for the <br /> Sangre de Cristo fault north of Tobin Creek. <br /> The northern segment corresponds to McCalpin's n~rth- <br /> west-trending segment north of Major Creek. This segment is <br /> approximately 42 km long and is characterized by relatively <br /> low uplift rates, although Holocene scarps are documented at <br /> three locations along this segment. In addition to the obser- <br /> vation of lower uplift rates for this northern segmen=, <br /> McCalpin indicates that displacements of Holocene, Pinedale <br />' and Bull Lake deposits decrease significantly in the ~~icinity <br /> of Cotton Creek. McCalpin did not attempt to further :study <br /> fault segmentation north of Cotton Creek, so it will be <br /> assumed that the entire 42 km zone is likely to rupture <br /> during a single event. <br /> The southern segment corresponds to McCalpin's n~>rth- <br /> west and north-trending zones (the east-trending zone is <br /> not considered significant). This zone extends 48 km :=rom <br /> Major Creek on the north to Blanca Creek on the south and <br />' has experienced high uplift rates. It is possible that: this <br /> <br />5 <br /> <br />