In spring 2013, observation systems at Utah’s Bingham Canyon copper mine detected ground movement in a hillslope surrounding the mine’s open pit. Out of caution, mine managers evacuated personnel and shut down production, waiting for the inevitable.
On April 10, at 9:30 p.m. and again at 11:05 p.m., the slope gave way and thundered down into the pit, filling in part of what had been the largest man-made excavation in the world. Later analysis estimated that the landslide was at the time the largest non-volcanic slide in recorded North American history. Now, University of Utah geoscientists have revisited the slide with a combined analysis of aerial photos, computer modeling, and seismic data to pick apart the details. The total volume of rock that fell during the slide was 52 million cubic meters, they report, enough to cover Central Park with 50 feet of rock and dirt. The slide occurred in two main phases, but researchers used infrasound recordings and seismic data to discover 11 additional landslides that occurred between the two main events. Modeling and further seismic analysis revealed the average speeds at which the hillsides fell: 81 mph for the first main slide and 92 mph for the second, with peak speeds well over 150 mph.
The study shows how the team’s methods can be used to remotely characterize a landslide, and the details they elicited from the data may be useful in planning for and modeling future landslide events.
The results are published in Journal of Geophysical Research-Earth Surface.
Animations of both phases of the slide can be found here:
Liu, Q., K. D. Koper, R. Burlacu, S. Ni, and F. Wang (2015). Observations of teleseismic body waves (P,SV,SH) in microseisms recorded by a large aperture array in China, Abstract S41B‐2757.
Koper, K. D., and R. Burlacu (2015). Location of P‐wave microseism sources via back‐projection of large aperture seismic array data, 26th International Union of Geology and Geophysics General Assembly, Prague, Czech Republic, June 22 ‐ July 2.
Batchelor, C. E., K. D. Koper, and K. L. Pankow (2015). Characterization of seismic swarms in Utah, Seism. Res. Lett. 86, 681.
Pankow, K. L., J. R. Stein, D. Chambers, and K. D. Koper (2015). Discriminating seismic sources (mining‐induced seismicity, fluid injection induced seismicity, and tectonic earthquakes) in Central Utah, USA, 26th International Union of Geology and Geophysics General Assembly, Prague, Czech Republic, June 22 ‐ July 2.
Koper, K., J. Hale, R. Burlacu, K. Goddard, A. Trow, L. Linville, J. Stein, D. Drobeck, and M. Leidig (2015). Dense seismic recordings of two surface‐detonated chemical explosions, Abstract S52B‐03.
Chambers, D. J. A., J. M. Wempen, M. K. McCarter, K. L. Pankow, and K. D. Koper (2015), Correlation of newly detected mining induced seismicity with subsidence in a Wyoming mining district, 2015 SME Annual Conference & Expo, Denver, Colorado, February 15‐18.
Chambers, D. J. A., M. K. McCarter, K. D. Koper, and K. L. Pankow (2015). Application of regional subspace detection to identify mining related seismicity, in Proc. of the 34th International Conference on Ground Control in Mining, Morgantown, West Virginia, July 28‐30.
Chambers, D. J. A., K. D. Koper, K. L. Pankow, and M. K. McCarter (2015). Subspace detection to detect small mining events: A comparison of catalogs, in Proc. of the 34th International Conference on Ground Control in Mining, Morgantown, West Virginia, July 28‐30.
Chambers, D. J. A., K. D. Koper, K. L. Pankow, and M. K. McCarter (2015). Detecting and characterizing coal mine related seismicity in the Western U.S. using subspace methods, Geophys. J. Intl., 203, 1388‐1399.