Hazards March 13, 2013 The Science of Sinkholes This video, from the U.S. Geological Survey, explores the geological factors behind sinkholes and the related science. Narrated by Randall Orndorff, the Director of the USGS Eastern Geology and Paleoclimate Science Center.
Earthquake damage: to interior adobe walls of residence Geology, Hazards August 23, 2011 Case Study: The Trinidad, Colorado Earthquakes [ED: Originally published in 2011 by Vincent Matthews, former State Geologist at the CGS.] Around midnight on August 22, 2011, Colorado experienced its largest earthquake in half a century. The earthquake was quickly relegated to obscurity by the 5.8 earthquake that occurred about 12 hours…
Hazards June 16, 2011 Mine Subsidence Hazards in Colorado This video, produced by the CGS in 2011, examines the significant geo-hazards related to the long history of underground coal mining in Colorado.
Hazards February 10, 2011 Hazardous Soils in Colorado This educational video, produced in 2011, explores the various problems that arise from hazardous soil conditions — expansive, collapsible/compressible, hydrocompactive, dispersive, swelling/expansible — across the state. These geologic hazards combined cause more infrastructure damage in Colorado than any others. The video also covers the types of damage, methods for prevention…
A close-up showing the scale of one of the blocks of Castle Rock Conglomerate that is already displaced Hazards July 10, 2009 Case Study: Rockfall – St. Francis of Assisi, Castle Rock The CGS studied the site of St. Francis of Assisi Church in Castle Rock extensively after a block detached from the upper cliff face in January 1981. The block presented a risk to homes at the base of the slope south of the church, and was subsequently broken up using…
Figure 3 -- This development in west Glenwood Springs constructed a rockfall impact wall above their townhomes to protect against both rockfall and mudslides (debris flows). Photo credit: Jon White for the CGS.|Figure 2 -- Several large rocks from the western wall of the Roaring Fork River in Glenwood Springs crashed into the houses below during the early morning causing significant damage Hazards July 6, 2005 Case Study: Rockfall – Glenwood Springs The town of Glenwood Springs in west-central Colorado lies at the confluence of the Roaring Fork and Colorado rivers. The town is tightly constrained by the steep river valleys so land-development pressure is causing residential growth to push into rockfall hazard areas. In West Glenwood, on the west side…
By August 2005 Hazards June 21, 2005 Case Study: Clear Creek Canyon rockslide Rockfalls and rock slides are common along transportation corridors in the Rocky Mountains. Clear Creek Canyon just west of Golden is one of the most active rockfall areas in Colorado. The canyon has been cut into Precambrian schists and gneisses by Clear Creek, one of the primary drainages in the…
Retaining wall settlement at the center of the image with the sorority houses in the background and the IM field in the foreground. Photo credit: T. C. Wait for the CGS.|The Rockwell clay mine area immediately south of the CSM campus along US 6 in 1977 before more recent reclamation as a golf course. The green area to the top left is part of the IM field where the subsidence occurred. Photo credit: Colorado Geological Survey.|DC resistivity survey crew from the engineering firm Zapata/Blackhawk laying out the multicore switch cables across the IM field area in 2008. Photo credit: T. C. Wait for the CGS.|Subsidence road damage near one of the sorority houses at CSM in August 2005. Photo credit: T. C. Wait for the CGS.|A drill-rig preparing boreholes for subsurface grouting under the IM field in August 2005. Photo credit: T. C. Wait for the CGS.|One of the several subsidence features in the IM field at the Colorado School of Mines in 2005. Photo credit: T. C. Wait for the CGS.|Figure from DC resistivity report from 2009 detailing some of the infrastructure Geology, Hazards April 26, 2005 Case Study: mine subsidence, CSM For decades, the west side of the Colorado School of Mines (CSM) main campus had subsidence issues related to historical mining activities. At one point, in the 1990s, one of the married student housing units in that area was so badly damaged that it was condemned. In the early…
A large sinkhole opened in January 2005 at the Ironbridge Development and Golf Course Hazards January 17, 2005 Case Study: Roaring Fork sinkhole [ED: This report from January 17, 2005 was written by Jon White, (Senior Engineering Geologist, Emeritus). Lightly edited for dated references it highlights a hazardous geological regime in the central Colorado Rockies around the Roaring Fork River Corridor.] Last week, while on the Western Slope, I was informed by…
Avalanche debris in the runout zone taken from a helicopter on the morning after the avalanche occurred Hazards March 24, 2003 Case Study: Avalanche – Silver Plume On March 23, 2003, a large avalanche occurred about one mile west of the Town of Silver Plume. The avalanche brought trees, rock, soil and snow to the valley floor, knocked down overhead utility lines, blocked the I-70 frontage road, damaged the town’s water treatment plant (WTP), and dammed Clear Creek. The dam was breached using explosives before the plant’s electric pump motors were flooded. With damage to the WTP’s chlorine contact tank and building, Silver Plum...
West view of the 2003 sinkhole showing proximity to campus buildings. Sunlight Ski Area is on the left horizon. Roaring Fork River valley is in left middle background below the ski area and in front of first row of ridges. Photo credit: Jon White for the CGS.|South close-up view of sinkhole wall showing uniform silt sediments derived from windblown deposits (loess). CMC maintenance staff had started to fill the sinkhole with broken road-pavement waste. Photo credit: Jon White for the CGS.|Sample of the loess from the wall of the sinkhole. Photo credit: Jon White for the CGS.|The sinkhole site Geology, Hazards February 4, 2003 Case Study: Colorado Mountain College, Spring Valley In early February of 2003, a 24-foot-wide (7.5 m) sinkhole spontaneously opened on a soccer field at the Colorado Mountain College (CMC) – Spring Valley campus, about 10 miles (16 km) southeast of Glenwood Springs in Garfield County. The CMC physical plant maintenance staff back-filled the hole with road pavement…
SP-43 A Guide to Swelling Soils for Colorado Homebuyers and Homeowners Hazards September 26, 2001 Swelling Soil Publication Wins Another National Award CGS Special Publication 43, SP-43 A Guide to Swelling Soils for Colorado Homebuyers and Homeowners, by Dave Noe, William “Pat” Rogers, and Candace Jochim, is the winner of the 2001 Edward B. Burwell, Jr. Award by the Geological…