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A model for earthquakes near Palisades Reservoir, southeast Idaho

Journal of Research of the U.S. Geological Survey
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Abstract

The Palisades Reservoir seems to be triggering earthquakes: epicenters are concentrated near the reservoir, and quakes are concentrated in spring, when the reservoir level is highest or is rising most rapidly, and in fall, when the level is lowest. Both spring and fall quakes appear to be triggered by minor local stresses superposed on regional tectonic stresses; faulting is postulated to occur when the effective normal stress across a fault is decreased by a local increase in pore-fluid pressure. The spring quakes tend to occur when the reservoir level suddenly rises: increased pore pressure pushes apart the walls of the graben flooded by the reservoir, thus decreasing the effective normal stress across faults in the graben. The fall quakes tend to occur when the reservoir level is lowest: water that gradually infiltrated poorly permeable (fault-gouge?) zones during high reservoir stands is then under anomalously high pressure, which decreases the effective normal stress across faults in the poorly permeable zones.

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Publication type Article
Publication Subtype Journal Article
Title A model for earthquakes near Palisades Reservoir, southeast Idaho
Series title Journal of Research of the U.S. Geological Survey
Volume 3
Issue 4
Year Published 1975
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Earthquake Science Center
Description 8 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Research of the U.S. Geological Survey
First page 393
Last page 400
Country United States
State Idaho
Other Geospatial Palisades Reservoir
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