Deformation of the Wasatch Front, Utah, from GPS measurements Abstract

abstract

  • We analyze 13 years of Wasatch fault GPS data, Utah, determining the magnitude and distribution of deformation. The Wasatch fault is a large normal fault that has been historically aseismic at the M3+ level. Yet GPS-derived extension rates of 2.4 ± 0.2 mm/yr exceed the predicted loading rates of 0.9-1.7 mm/yr obtained from paleoseismic studies. The strain rate field is interpolated to reveal that maximum Wasatch-related extension at ~40.5º is 0.055 x 10-6 ± 0.05 x 10-6 1/yr, corresponding to 3 ± 2 mm/yr westward motion across a 50-km baseline. The northern Utah segments have maximum strain rates of 0.001-0.002 x 10-6 ± 0.04 x 10-6 1/yr, corresponding to 0.05-0.1 ± 2 mm/yr. However, the strain rate field suggests that deformation in northern Utah may be distributed across not just the Wasatch fault, but also the East Cache fault and East Great Salt Lake fault. Profiles of velocity components show that that the cumulative deformation in northern Utah is comparable to that of the southern and central segments of the Wasatch fault. The northern profile has a cumulative westward motion of 3.1 ± 0.2 mm/yr, while the central profile attains 2.3 ± 0.3 mm/yr westward motion and southern profile reaches 2.4 ± 0.3 mm/yr cumulative motion. The profiles are compared with fault dislocation models in a preliminary analysis of potential subsurface fault geometries.

publication date

  • 2010

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