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West Salt Creek rock avalanche viewed from the air, May 2014. Photo credit: David Noe for the CGS

Top-Ten paper at GSA

2017-01-23 | Dr. John Hopkins

On May 25, 2014 the longest landslide in Colorado’s historical record occurred in west-central Colorado, six miles southeast of the small town of Collbran in Mesa County, taking the lives of three local men. The landslide was 2.8 miles long, covered almost a square mile of the West Salt Creek valley and the net volume displacement was 38 million yd3.  The fast-moving (40-85 MPH), high-mobility landslide was caused by an initial rotational slide of a half-mile-wide block of Eocene Green River Formation. The resultant rock failures, rockmass disaggregation, and mostly valley-constrained rock avalanche, dropped approximately 2,100 ft in elevation as a rapid series of cascading surges of chaotic rubble composed of fragments of pulverized rock, vegetation, topsoil, and mud. Local seismometers recorded a magnitude 2.8 earthquake from the event with a seismic wave train duration of approximately three minutes. The toe of the landslide came within 200 ft of active gas-production wellheads and loss of irrigation ditches and water impacted local ranches and residents.

The CGS’s Matt Morgan and Jon White were two of the co-authors on one of the top-ten Geological Society of America (GSA) 2016 book chapters and journal articles, this out of 600 papers. The article describes a comprehensive forensic analysis of the massive West Salt Creek rock avalanche that occurred in late May 2014 in western Colorado (USA). The analysis relied on large-scale (1:1000) structural mapping accomplished via high-resolution unmanned aircraft system imagery along with seismic data generated by more than twenty stations within approximately 500 miles (800 km) of the event. The avalanche was the largest mass-movement slope failure in the historical record of Colorado: it killed three people and narrowly avoided destroying a gas wellhead.

This paper was just one of the outcomes of CGS research into the causes of the West Salt Creek landslide. A comprehensive (and also award-winning) report, Bulletin 55 – The West Salt Creek Landslide: A Catastrophic Rockslide and Rock/Debris Avalanche in Mesa County details the entire scope of the geoscience work that the CGS and other agencies did on the catastrophic event.

West Salt Creek rock avalanche viewed from the air, May 2014. Photo credit: David Noe for the CGS

West Salt Creek rock avalanche viewed from the air, May 2014. Photo credit: David Noe for the CGS

Head scarp of the West Salt Creek rock avalanche, Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

Head scarp of the West Salt Creek rock avalanche, Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

Looking down the West Salt Creek rock avalanche from the head scarp. Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

Looking down the West Salt Creek rock avalanche from the head scarp. Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

The gas well pad near the terminus of the West Salt Creek rock avalanche (flow direction right to left), Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

The gas well pad near the terminus of the West Salt Creek rock avalanche (flow direction right to left), Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

Near vertical view of the initial end point of the West Salt Creek rock avalanche (flow direction from left to right), Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

Near vertical view of the initial end point of the West Salt Creek rock avalanche (flow direction from left to right), Mesa County, Colorado, May 2014. Photo credit: David Noe for the CGS.

Citations, Categories & Tags

Citations

Coe, Jeffrey A., Rex L. Baum, Kate E. Allstadt, Bernard F. Kochevar, Robert G. Schmitt, Matthew L. Morgan, Jonathan L. White, Benjamin T. Stratton, Timothy A. Hayashi, and Jason W. Kean. 2016. "Rock-Avalanche Dynamics Revealed by Large-Scale Field Mapping and Seismic Signals at a Highly Mobile Avalanche in the West Salt Creek Valley, Western Colorado." Geosphere 12 (2): 607–31. doi:10.1130/GES01265.1. White, Jonathan L., Matthew L. Morgan, and Karen A. Berry. “Bulletin 55 - The West Salt Creek Landslide: A Catastrophic Rockslide and Rock/Debris Avalanche in Mesa County.” Bulletin. Golden, CO: Colorado Geological Survey, 2015. Bulletin 55. https://coloradogeologicalsurvey.org/publications/west-salt-creek-landslide-catastrophic-rockslide-avalanche-mesa-colorado/.

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Hazards, Publications

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