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Active steady-state creep on a nontectonic normal fault in southeast Utah: Implications for strain release in a rapidly deforming salt system

Geophysical Research Letters
By: , , , and 
https://doi.org/10.1029/2020GL087081

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Abstract

Characterizing short-term temporal variations of fault creep provides insight into the evolution, mechanics, and strength of fault systems. Using spirit leveling and an extensome- ter, we measured surface displacement of a fault southwest of the Needles District, Canyon- lands National Park, Utah, where extension is driven by differential unloading of a subsur- face salt layer due to incision of the Colorado River. Results show continuous creep at max- imum rates of 0.7±0.2 mm/yr without large temporal variations typical of episodic creep events. Occasional, minor transient events in fault slip velocity coincided with water infil- tration; however, we found no significant relationship between precipitation and transient events. Detailed mapping of regionally widespread, fault-parallel sinkholes provide evidence for dilation of faults at shallow depth, a process that lowers fault strength. We propose con- tinuous slip is related to low fault strength and differential unloading, as opposed to other salt systems where dissolution has been linked to episodic slip.

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Publication type Article
Publication Subtype Journal Article
Title Active steady-state creep on a nontectonic normal fault in southeast Utah: Implications for strain release in a rapidly deforming salt system
Series title Geophysical Research Letters
DOI 10.1029/2020GL087081
Volume 47
Issue 11
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Pacific Coastal and Marine Science Center
Description e2020GL087081, 10 p.
Country United States
Other Geospatial Southeastern Utah
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