2010 Mount Meager landslide

2010 landslide in British Columbia, Canada 2010 Mount Meager landslide File:2010 Mount Meager landslide.jpg 300 The 2010 Mount Meager landslide in 2014 2010 08 06Guthrie Friele Allstadt Roberts 2012 3:27 a.m. PDTGuthrie Friele Allstadt Roberts 2012 British Columbia, Canada 50 37 22 N 123 30 03 W region:CA-BC_type:event inline,title Rockslide/debris flowGuthrie Friele Allstadt Roberts 2012 Slope failureGuthrie Friele Allstadt Roberts 2012 NoneGuthrie Friele Allstadt Roberts 2012 Nonehttp://www.cbc.ca/news/canada/british-columbia/evacuation-ordered-after-b-c-landslide-1.892478 Evacuation ordered after B.C. landslide CBC News 2010-08-06 2018-03-09 C$10 millionGuthrie Friele Allstadt Roberts 2012 The 2010 Mount Meager landslide was a large catastrophic debris avalanche that occurred in southwestern British Columbia, Canada, on August 6 at 3:27 a.m. PDT (UTC-7). More than 45000000 m3 ft3 on of debris slid down Mount Meager, temporarily blocking Meager Creek and destroying local bridges, roads and equipment. It was one of the largest landslides in Canadian history and one of over 20 landslides to have occurred from the Mount Meager massif in the last 10,000 years. Although voluminous, there were no fatalities caused by the event due in part to its remote and uninhabited location. The landslide was large enough to send seismic waves more than 2000 km mi on away into the neighbouring U.S. states of Alaska and Washington and beyond. Multiple factors led to the slide: Mount Meager's weak slopes have left it in a constant state of instability. Background Mount Meager, located 150 km mi on north of Vancouver, is a peak of the Mount Meager massif.Wood Kienle 1992 91Simpson Stasiuk Shimamura Clague 2006 681 This is a group of coalescent stratovolcanoes and the largest volcanic centre in the Garibaldi Volcanic Belt.Roberti Friele van Wyk de Vries Ward 2017 369Friele Jakob Clague 2008 48–50 It comprises about 20 km3 mi3 on of eruptive rocks that were deposited during four distinct eruptive periods, the first beginning 2.2 million years ago.Friele Jakob Clague 2008 48–50Wood Kienle 1992 141 During the present period (beginning 150,000 years ago), it has erupted more than five times, producing ash falls, pyroclastic flows, lava flows and lahars.Wood Kienle 1992 141Read 1990 167–170Hickson Russell Stasiuk 1999 489 The only identified Holocene eruption was in about 410 BC and created a diverse sequence of volcanic deposits well exposed along the Lillooet River.Hickson Russell Stasiuk 1999 489320180 Meager 2018-03-06 This is the most recent major explosive eruption in British Columbia, as well as the largest known Holocene explosive eruption in Canada.Hickson Russell Stasiuk 1999 489 The massif has been a source of large volcanic debris flows for the last 8,000 years, many of which have reached several tens of kilometres downstream in the Lillooet River valley.Friele Jakob Clague 2008 48–50 It is arguably the most unstable mountain massif in Canada and may also be its most active landslide area.Friele Jakob Clague 2008 48–50Guthrie Friele Allstadt Roberts 2012 The earliest identified Holocene landslide was in 7900 BP and further landslides occurred in 6250 BP, 5250 BP, 4400 BP, 2600 BP, 2400 BP, 2240 BP, 2170 BP, 1920 BP, 1860 BP, 870 BP, 800 BP, 630 BP, 370 BP, 210 BP, 150 BP and in 1931, 1947, 1972, 1975, 1984, 1986 and 1998.Friele Jakob Clague 2008 48–50 These events were attributed to structurally weak volcanic rocks, glacial unloading, recent explosive volcanism and Little Ice Age glacial activity.Guthrie Friele Allstadt Roberts 2012 Landslide thumb|right|The Meager Creek barrier after the dam outburst flood at the confluence of Capricorn and Meager creeks. At 3:27 a.m. PDT on August 6, 2010, the southern 2554 m ft on peak of Mount Meager collapsed in a series of major rockfalls. The rockfalls fell approximately 500 m ft on onto Meager's weak and heavily saturated south flank where they destabilized a significant volume of material, forming a highly mobile, very rapid debris flow. The debris flow travelled the entire 7 km mi on length of Capricorn Creek then inundated both the Meager Creek and Lillooet River valleys. Meager Creek was dammed for about 19 hours during which time water had built up behind the dam to create a 1.5 km mi on long lake. The landslide dam ultimately failed into the Lillooet River valley, releasing roughly 2650000 m3 ft3 on of water towards Pemberton with an average velocity of approximately 2.5 m/s ft/s on.Guthrie Friele Allstadt Roberts 2012 No deaths or injuries were associated with the event.Guthrie Friele Allstadt Roberts 2012 A study conducted by Guthrie et al. (2012) concluded that groundwater played a key role in the collapse. Prior to failure the flanks of Meager were subject to high pore water pressures indicated by extensive surface seepage observed throughout the failure surface and along lateral shears following the 2010 event. The largest visible bedrock spring occurred along the west lateral scarp and was the location of at least two previous landslides, occurring in 1998 and 2009. Water supply was exacerbated by summer melt of snow and ice, causing even greater saturation of slopes.Guthrie Friele Allstadt Roberts 2012 With a volume of approximately 48500000 m3 ft3 on, the 2010 landslide was comparable in volume to the 1965 Hope Slide, making it one of the largest in Canadian history.Guthrie Friele Allstadt Roberts 2012Litton Jackson 2014 2014 The landslide consisted mainly of intrusive porphyritic rhyodacite, lava flows and breccia derived from the Capricorn and Plinth assemblages, which are the most recently formed geological formations comprising the Mount Meager massif.Roberti Friele van Wyk de Vries Ward 2017 369 Impact Despite the remote location of the landslide, the event had considerable socioeconomic impact. Approximately 110000 m3 ft3 on of wood was stripped away from the slopes of Capricorn Creek and Meager Creek and the Lillooet River valley bottom and either pulverized into fine organic material or transported as large woody debris into the river system. The wood was a mixture of western hemlock, amabilis and subalpine firs, western red cedar and to a lesser extent lodgepole pine and balsam poplar. The total potential loss based on the markets at the time of the event was C$8.7 million. In addition, road construction equipment and two forest service bridges were destroyed, along with several kilometres of roads including almost 6 km mi on of the Meager Creek forest service road.Guthrie Friele Allstadt Roberts 2012 thumb|right|600px|alt=|Raw seismic signals from 2010 Mount Meager landslide recorded across southwestern British Columbia and northern Washington. Station and landslide location indicated on inset map. The landslide and the subsequent threat of a dam outburst flood on Meager Creek caused the evacuation of approximately 1,500 residents in the lower Lillooet River valley for one night and rescue efforts for several campers and workers in the vicinity of Mount Meager. Sediment moving downstream puts pressure on the Pemberton district diking system, raising the effective flood levels. The obliteration of Capricorn Creek and inundation of Meager Creek will have long-lasting environmental effects. In total, direct costs associated with the event were estimated at C$10 million. If gravel removal or dike elevation changes become necessary as a result of the increased sediment load, the total long-term costs of this landslide could exceed the direct costs.Guthrie Friele Allstadt Roberts 2012 Seismic signature The landslide generated long-period seismic waves that were visible at seismograph stations from southern California to northern Alaska, up to 2800 km mi on away. No known earthquake was associated with the failure, but the event itself was assigned an equivalent local magnitude of 2.6 by the Canadian National Seismograph Network.Guthrie Friele Allstadt Roberts 2012 Landslides do not always generate identifiable seismic signatures due in part to their slower source process and poor ground coupling as compared to earthquakes. Seismic energy conversion rates for similar events are estimated to be as low as 0.01% of the kinetic energy and 1% of the potential energy released by the slide. It requires an extremely energetic source to generate waves high enough in amplitude to be visible for thousands of kilometres. The seismogenic nature of this landslide was a result of the large volume of material involved and the extremely rapid velocities.Guthrie Friele Allstadt Roberts 2012 Eyewitnesses Four people witnessed the event and were in extreme jeopardy on several occasions during and immediately following the landslide. K. Kraliz, J. Duffy, J. Tilley and P. Smith arrived at upper Lillooet forest campsite at 3:25 a.m. PDT and began unloading their gear. They were surprised by "two large cracks" (loud explosive noises, not physical cracks in the ground) occurring in quick succession, followed by a rumbling that initially sounded like a train or a forest fire, but that grew to a deafening volume in about 20 seconds. All four campers got back into their truck and headed for higher ground. Chaos ensued for the next few hours before daylight as they encountered debris flows, mud, falling trees and other hazards at the edge of the landslide deposit in the Lillooet River valley.Guthrie Friele Allstadt Roberts 2012 Perhaps the most alarming part of their story occurred as they came face to face with a 1.5 m ft on high wall of mud and water that appeared to them like a "turbulent bubbling wedge of black oil". They turned their truck around, but not before they were overtaken by the hyperconcentrated flow. Accelerating rapidly, they nonetheless escaped, in what P. Smith described as most resembling "the Millennium Falcon escaping the Death Star explosion at the end of Return of the Jedi". The two large cracks heard by the witnesses may have been caused by the impact of Meager's failed secondary peak.Guthrie Friele Allstadt Roberts 2012 Significance The 2010 landslide is significant for seven reasons:Guthrie Friele Allstadt Roberts 2012 It was the tenth mass flow involving volumes in excess of 500000 m3 ft3 on to have occurred at the Mount Meager massif since 1850 and the sixth largest mass flow identified at the volcano over the Holocene. It was one of the largest landslides to have occurred worldwide since 1945. The landslide exhibited dramatic transformation from an initial rock slope failure to a rapidly moving debris flow as a result of the high degree of fragmentation of the initial failure mass. The formation of a significant landslide dam illustrated the importance of landslide damming as a secondary landslide process and as a hazard to distant downstream communities. The seismic trace of the landslide initiation and motion allowed detailed reconstruction of the stages and velocity of movement. The event demonstrated the role of rapid post-Little Ice Age deglaciation in destabilizing slopes adjacent to modern glaciers. It represented a unique opportunity to consider hazard and risk from catastrophic failures to mountain communities. The event illustrated the extreme landslide hazard of glacier-clad dissected Quaternary volcanic centres, which results from the existence of steep slopes in poor quality rock (reflecting such factors as hydrothermal alteration and heterogeneity of volcanic products). In this geological environment, landslides are a major process of denudation and, through transformation into debris flows, deliver large volumes of debris to river systems.Guthrie Friele Allstadt Roberts 2012 See also List of landslides Hope Slide Frank Slide References https://www.nat-hazards-earth-syst-sci.net/12/1277/2012/ The 6 August 2010 Mount Meager rock slide-debris flow, Coast Mountains, British Columbia: characteristics, dynamics, and implications for hazard and risk assessment 829815343 Guthrie et al. Footnotes 30em Sources Read Peter B. 1990 Mount Meager Complex, Garibaldi Belt, Southwestern British Columbia https://journals.lib.unb.ca/index.php/GC/article/view/3672 Geoscience Canada 17 3 1911-4850 Wood Charles A. Volcanoes of North America: United States and Canada Kienle Jürgen Cambridge University Press 1992 9780521438117 Cambridge Paperback Hickson C. J. Catherine Hickson Russell J. K. Stasiuk M. V. 1999 Volcanology of the 2350 B.P. Eruption of Mount Meager Volcanic Complex, British Columbia, Canada: implications for Hazards from Eruptions in Topographically Complex Terrain Bulletin of Volcanology Springer Science+Business Media 60 7 489–507 1999BVol...60..489H 10.1007/s004450050247 0258-8900 53421677 17181673 Simpson K.A. Stasiuk M. Shimamura K. Clague J.J. Friele P. 2006 Evidence for catastrophic volcanic debris flows in Pemberton Valley, British Columbia https://www.sfu.ca/~qgrc/papers/Simpson%20et%20al.%20CJES.pdf Canadian Journal of Earth Sciences Ottawa NRC Research Press 43 6 679-689 2006CaJES..43..679S 10.1139/E06-026 0008-4077 1480-3313 2327862 241432244 Friele Pierre Jakob Matthias Clague John 2008 Hazard and risk from large landslides from Mount Meager volcano, British Columbia, Canada Georisk Taylor & Francis 2 1 48–64 10.1080/17499510801958711 2008GAMRE...2...48F 1749-9518 15157361 12310606 237635790 Guthrie R. H. Friele P. Allstadt K. Kate Allstadt Roberts N. Evans S. G. Delaney K. B. Roche D. Clague J. J. Jakob M. 2012 The 6 August 2010 Mount Meager rock slide-debris flow, Coast Mountains, British Columbia: characteristics, dynamics, and implications for hazard and risk assessment https://volcanoes.usgs.gov/vsc/file_mngr/file-87/nhess-12-1277-2012-Meagerlandslide.pdf Natural Hazards and Earth System Sciences English 12 5 1277–1294 2012NHESS..12.1277G 10.5194/nhess-12-1277-2012 1561-8633 55793271 258685686 free Litton Evie https://books.google.com/books?id=LERsBAAAQBAJ Hiking Hot Springs in the Pacific Northwest: A Guide to the Area's Best Backcountry Hot Springs Jackson Sally FalconGuides 2014 978-0-7627-8370-0 Google Books Roberti Gioachino Friele Pierre van Wyk de Vries Benjamin Ward Brent Clague John J. Perotti Luigi Giardino Marco 2017 Rheological evolution of the Mount Meager 2010 debris avalanche, southwestern British Columbia Geosphere Geological Society of America 13 2 369–390 10.1130/GES01389.1 free 2017Geosp..13..369R 2318/1635824 free External links https://www.ctvnews.ca/vancouver/article/state-of-emergency-declared-after-bc-slide/ https://web.archive.org/web/20141218175257/http://bc.ctvnews.ca/state-of-emergency-declared-after-b-c-slide-1.539622 live December 18, 2014 August 6, 2010 State of emergency declared after B.C. slide CTV News https://www.theglobeandmail.com/news/british-columbia/bc-landslide-may-be-over-but-debris-expected-to-wreak-more-havoc/article1376305/ August 8, 2010 B.C. landslide may be over, but debris expected to wreak more havoc The Globe and Mail https://thetyee.ca/News/2010/08/12/MeagerLandslide/ August 12, 2010 Stunning Photos of Massive Meager Slide The Tyee http://www.whistlerquestion.com/news/pemberton/meager-slide-one-year-later-1.1281960 August 4, 2011 Meager slide: One year later Whistler Question Category:Mount Meager massif Category:Landslides in Canada Category:Landslides in 2010 Category:2010 in British Columbia Category:Natural disasters in British Columbia Category:21st-century volcanic events Category:2010 disasters in Canada Category:Volcanic landslides Category:Holocene British Columbia