Landslide area during melt seasons before, just after the landslide, and debris moving down glacier
Seismic data on 28 June 2016 indicated a very large landslide released the equivalent energy of a magnitude 5.2 earthquake in Glacier Bay National Park, Alaska. Researchers at Lamont-Doherty Earth Observatory not only identified when the 1.2 km high (4000 ft) mountainside released a mass estimated at 120 million metric tons (132 million short tons) within the Park but also additional details of the event such as how rapidly it moved. The total mass of the slide is the equivalent of some 60 million mid-size SUVs.
Local pilots, followed by satellite imagery, soon confirmed the exact location of the ~9 km (5.5 mi) long landslide debris field on Lamplugh Glacier. In the past 250 years, glaciers have retreated back up Glacier Bay over 100 miles. This significant ice loss means the steep mountainsides are no longer buttressed by ice and, as a result, the area is prone to landslides. Here it is easy to see the landslide material because the dark rock strongly contrasts with the brighter ice and snow of the glacier. The images presented here show the area affected by the landslide before the collapse, then as the thick layer of debris has begun to move down glacier at about 90 m/yr (~300 ft/yr) towards Johns Hopkins Inlet, an arm of Glacier Bay. The July 2016 front position is shown in yellow on subsequent images.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 220.127.116.11.0