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Comparison of geodetic and geologic data from the Wasatch region, Utah, and implications for the spectral character of Earth deformation at periods of 10 to 10 million years

Friedrich, Anke M. and Wernicke, Brian P. and Niemi, Nathan A. and Bennett, Richard A. and Davis, James L. (2003) Comparison of geodetic and geologic data from the Wasatch region, Utah, and implications for the spectral character of Earth deformation at periods of 10 to 10 million years. Journal of Geophysical Research B, 108 (B4). Art. No. 2199. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20140721-123455534

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Abstract

The Wasatch fault and adjacent fault zones provide an opportunity to compare present-day deformation rate estimates obtained from space geodesy with geologic displacement rates over at least four temporal windows, ranging from the last millennium up to 10 Myr. The three easternmost GPS sites of the Basin and Range Geodetic Network (BARGEN) at this latitude define a ∼130-km-wide region spanning three major normal faults extending east-west at a total rate of 2.7 ± 0.4 mm/yr, with an average regional strain rate estimated to be 21 ± 4 nstrain/yr, about twice the Basin and Range average. On the Wasatch fault, the vertical component of the geologic displacement rate is 1.7 ± 0.5 mm/yr since 6 ka, <0.6 mm/yr since 130 ka, and 0.5–0.7 mm/yr since 10 Ma. However, it appears likely that at the longest timescale, rates slowed over time, from 1.0 to 1.4 mm/yr between 10 and 6 Ma to 0.2 to 0.3 mm/yr since 6 Ma. The cumulative vertical displacement record across all three faults also shows time-variable strain release ranging from 2 to 4 mm/yr since 10 ka to <1 mm/yr averaged over the past 130 kyr. Conventional earthquake recurrence models (“Reid-type” behavior) would require an accordingly large variation in strain accumulation or loading rate on a 10-kyr timescale, for which there appears to be no obvious geophysical explanation. Alternatively, seismic strain release, given a wide range of plausible constitutive behaviors for frictional sliding, may be clustered on the 10-kyr timescale, resulting in the high Holocene rates, with comparatively low, uniform strain accumulation rates on the 100-kyr timescale (“Wallace-type” behavior). The latter alternative, combined with observations at the million-year timescale and the likelihood of a significant contribution of postseismic transients, implies maxima of spectral amplitude in the velocity field at periods of ∼10 Myr (variations in tectonic loading), ∼10 kyr (clustered strain release), and of 100 years (postseismic transients). If so, measurements of strain accumulation and strain release may be strongly timescale-dependent for any given fault system.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2001JB000682DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/2001JB000682/abstractPublisherArticle
ORCID:
AuthorORCID
Wernicke, Brian P.0000-0002-7659-8358
Additional Information:© 2003 The American Geophysical Union. Received 22 June 2001; Revised 2 June 2002; Accepted 21 November 2002; Published 15 April 2003. This research was supported by National Science Foundation grants EAR-97-25766 and 99-03366 awarded to B. Wernicke and NASA grant NAG5-8226 and USGS 99HQGR0212 awarded to R. Bennett. We thank F. Albarede, W. Thatcher, S. Wesnousky and an anonymous reviewer for constructive comments that greatly improved the presentation. We thank J. Bartley, D. Currey, K. Haller, M. Machette, K. Hanson, E. Lips, A. Mattson, S. Olig, J. Pechman, M. Simons, and R. B. Smith for useful discussions on the geophysics and Quaternary history of the Wasatch region. Special thanks to D. Dinter and J. Pechmann for permission to discuss unpublished data on the seismic history of the East Great Salt Lake fault and to E. Lips for permission to discuss unpublished data on the late Quaternary history of the Little Cottonwood area.
Funders:
Funding AgencyGrant Number
NSFEAR-97-25766
NSFEAR-99-03366
NASANAG5-8226
USGS99HQGR0212
Subject Keywords:geodetic, geologic, fault slip rate, normal fault, timescale, earthquake cycle
Issue or Number:B4
Record Number:CaltechAUTHORS:20140721-123455534
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140721-123455534
Official Citation:Friedrich, A. M., Wernicke, B. P., Niemi, N. A., Bennett, R. A., & Davis, J. L. (2003). Comparison of geodetic and geologic data from the Wasatch region, Utah, and implications for the spectral character of Earth deformation at periods of 10 to 10 million years. Journal of Geophysical Research: Solid Earth, 108(B4), 2199. doi: 10.1029/2001jb000682
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47366
Collection:CaltechAUTHORS
Deposited By: Joanne McCole
Deposited On:21 Jul 2014 20:48
Last Modified:03 Oct 2019 06:53

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