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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 109,
B11310,
19 PP., 2004
doi:10.1029/2004JB003159
Tomographic imaging of late Quaternary faulting, Oquirrh Mountains, Utah
Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, USA
Seismic tomography can be used to image colluvial material in the subsurface by inverting first arrival travel times for velocity. Colluvial material deposited at the base of a fault-scarp free face often appears as a low-velocity zone (LVZ) on a tomogram because it is generally less compacted and cemented than the surrounding alluvium. A tomogram generated from a forward model of a synthetic velocity structure successfully images two LVZs stacked in the hanging wall of a normal fault. The Mercur fan, Oquirrh Mountains, Utah, provides an opportunity to look for stacked LVZs in a distributed fault zone. Three tomographic images across fault scarps on an intermediate age alluvial fan can be used to identify two stacked low-velocity zones. Interpretation of a fourth tomogram is less conclusive. These two low-velocity zones are interpreted as colluvial packages separated by higher-velocity alluvial material and suggest that tectonic activity is interspersed with pulses of fan building.
Received 30 April 2004; accepted 22 September 2004; published 30 November 2004.
Citation: (2004), Tomographic imaging of late Quaternary faulting, Oquirrh Mountains, Utah, J. Geophys. Res., 109, B11310, doi:10.1029/2004JB003159.
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