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How similar was the 1983 Mw 6.9 Borah Peak earthquake rupture to its surface-faulting predecessors along the northern Lost River fault zone (Idaho, USA)?

February 16, 2022

We excavated trenches at two paleoseismic sites bounding a trans-basin bedrock ridge (the Willow Creek Hills) along the northern Lost River fault zone to explore the uniqueness of the 1983 Mw 6.9 Borah Peak earthquake compared to its prehistoric predecessors. At the Sheep Creek site on the southernmost Warm Springs section, two earthquakes occurred at 9.8−14.0 ka (95% confidence) and 6.5−7.1 ka; each had ∼1.9 m of vertical displacement. About 4 km to the southeast, across the Willow Creek Hills, two ruptures at the Arentson Gulch site on the northernmost Thousand Springs section occurred at 9.0−14.7 ka and 6.1−7.5 ka with ∼1.9 m of vertical displacement each. We synthesize these and previous paleoseismic results into a model of five postglacial (

Publication Year 2022
Title How similar was the 1983 Mw 6.9 Borah Peak earthquake rupture to its surface-faulting predecessors along the northern Lost River fault zone (Idaho, USA)?
DOI 10.1130/B36144.1
Authors Christopher DuRoss, Richard W. Briggs, Ryan D. Gold, Alexandra Elise Hatem, Austin John Elliott, Jaime Delano, Ivan Medina-Cascales, Harrison J. Gray, Shannon A. Mahan, Sylvia Nicovich, Zachery Lifton, Emily J. Kleber, Greg N. McDonald, Adam Hiscock, Mike Bunds, Nadine G. Reitman
Publication Type Article
Publication Subtype Journal Article
Series Title Geological Society of America Bulletin
Index ID 70230642
Record Source USGS Publications Warehouse
USGS Organization Geologic Hazards Science Center
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