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Show 52 Daniela Anguita college of mines & earth sciences The North-South trending Wasatch Fault Zone (WFZ) extends for ~370 km from southern Idaho into central Utah, and is subdivided into ten seismogenically independent segments possessing unique paleoearthquake chronologies. The Salt Lake City fault segment extends for ~35 km along the eastern margin of the city with a large step-over directly west of Neffs Canyon. Two faults running perpendicular to the Wasatch Fault has been previously mapped in Neffs Canyon and identified as the Mount Raymond transverse zone (MRTZ), yet no relationship has been established between the two fault zones. Detailed mapping of this intersection shows a complicated structural zone with an unconformity omitting a minimum of 100 My. Bedding has been tilted to the North by ~65°, with a series of beds folding in what might be recent reactivation of the MRTZ fault surface through Wasatch Fault movement. The mechanism controlling recent movement on the faults perpendicular to the Wasatch Fault may greatly affect the ge-ometry and behavior of the Wasatch Fault itself and possibly explain the step-over. Evidence of the MRTZ faults includes faceted hill slopes, pervasive occurrence of brecciated rocks, apparent offsets of rock forma-tions, and an adjacent East-West trending gravity anomaly in the Salt Lake Valley. Smaller normal faults that terminate against the MRTZ are a good indication that the larger Wasatch Fault may do the same. The suggested model explains WFZ trace migration as a result of unfavorable seismic energy dissipation by the MRTZ. Dee Foundation UROP Scholar 2011-2012 REEVALUATION OF FAULT SEGMENTATION AND EARTHQUAKE GEOLOGY IN NEFFS CANYON, SALT LAKE CITY, UTAH Daniela Anguita (Ronald L. Bruhn) Department of Geology and Geophysics University of Utah UNDERGRADUATE RESEARCH ABSTRACTS Ronald L. Bruhn |
