ON-001 Colorado Earthquake and Fault Map|Great Colorado ShakeOut contest illustration. General, Hazards September 23, 2022 The Great Colorado ShakeOut 2022 It’s coming up in less than four weeks! The Great Colorado ShakeOut is a public earthquake drill that takes place every year on the third Thursday of October across the state, the country, and the world. This year the official collective drill takes place Thursday, October 20th, 2022, at 10:20…
Earthquake damage: significant cracking and displacement in adobe wall of garage Geology, Hazards August 16, 2022 The Great ShakeOut The origins of The Great ShakeOut project lie, unsurprisingly, in Southern California, one of the more seismically active regions of the country. In 2008 a group of experts collaboratively modeled what might happen when a major earthquake hits the Southern California region. The detailed report, titled…
Munroe Quarry near Livermore Geology, Hazards April 11, 2022 Case Study: Lykins Formation Small but significant areas of Colorado are underlain by bedrock that is composed of evaporative minerals. These are salts and sulfates that precipitate out of salt-concentrated surface waters. In the geologic past these minerals were deposited in shallow seas within closed or restricted basins where…
Helicorder trace from Trinidad seismometer station Geology, Hazards March 25, 2022 CGS Seismic Stations Early History The Colorado School of Mines first acquired and installed a single three-component seismograph in the Cecil H. Green Observatory at Bergen Park, about 9 mi (14 km) southwest of Golden. That system was in continuous high-gain operation into the 1980s and was, during that…
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…
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…
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…