DETERMINATION OF PALEOEARTHQUAKE TIMING AND MAGNITUDES ON THE SOUTHERN SEGMENT OF THE EAST CACHE FAULT, UTAHUSGS NEHRP Grant 07HQGR0079, Final Technical Report (2012)
AbstractWe investigated the late Quaternary rupture history of the southern East Cache Fault zone [ECFZ], northern Utah with geologic mapping, paleoseismic logging of fault trenches, ground-penetrating radar, and optically stimulated luminescence dating. McCalpin (1989) indicated that the southern segment of the ECFZ consisted of three strands. We excavated four trenches across these strands, and evaluate the stratigraphy and structure of the sites. We conclude that the western fault strand of the ECFZ has had no late Quaternary displacement or does not exist; the central strand has not had any late Quaternary movement and may be a drape fold; and the eastern (range-front) strand has had one movement younger than 59-63 ka but older than the Bonneville lake cycle. The results of this study indicate that the late Quaternary slip rate on the southern segment has been significantly lower than that of the central segment. On the southern segment the elapsed time since the MRE is at least 26 ka (30 ka if connected to the James Peak MRE rupture), and may be as much 46 ka, which is much longer than the elapsed time (4 ka) and recurrence interval (9-11 ka) of the central segment.
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Citation InformationJames P. McCalpin. "DETERMINATION OF PALEOEARTHQUAKE TIMING AND MAGNITUDES ON THE SOUTHERN SEGMENT OF THE EAST CACHE FAULT, UTAH" USGS NEHRP Grant 07HQGR0079, Final Technical Report (2012)
Available at: http://works.bepress.com/james_mccalpin/11/