{"id":35269,"date":"2020-10-16T07:30:01","date_gmt":"2020-10-16T07:30:01","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=35269"},"modified":"2020-10-16T14:10:27","modified_gmt":"2020-10-16T14:10:27","slug":"harrison-lake","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2020\/10\/16\/harrison-lake\/","title":{"rendered":"Harrison Lake: newly discovered, large, ancient landslides in Canada"},"content":{"rendered":"

Harrison Lake: newly discovered, large, ancient landslides in Canada<\/h4>\n

There is increasing interest in the hazards associated with large landslides into enclosed bodies of water, such as fjords and lakes.  Examples include the famous Lituya Bay landslide<\/a> and the ongoing concerns about the potential for a major failure at Barry Arm<\/a>, both in Alaska.  Clearly large landslides are a hazard in themselves, but in general the main worry is the potential for a destructive landslide-induced tsunami<\/a> that can travel large distances in an enclosed water body.<\/p>\n

An interesting open access paper has just been published in the journal Landslides<\/em><\/a> (Hughes et al.<\/em> 2020<\/a>), which examines newly discovered deposits of three large landslides in the bed of  Harrison Lake, in southwest British Columbia.  The landslides were discovered during a bathymetric survey of the lake floor, and have then been investigated in more detail through seismic imaging.  This is the location, as shown on Google Earth:-<\/p>\n

\"Harrison

The location of Harrison Lake, as shown on Google Earth<\/p><\/div>\n

.<\/p>\n

The largest failure, termed the Mount Douglas landslide, which was a subaerial rock avalanche, has a volume of 2.4 million cubic metres.  Of the other two, the Mount Breakenridge landslide, which was a rockslide, has a volume of 1.3 million cubic metres and the nicely named Silver Mountain landslide has a volume of 200,000 cubic metres. The landslide deposits are blocky and flow-like, suggesting that they were emplaced rapidly.  Given the volumes, the two largest landslides into Harrison Lake, which both had a runout distance of over a kilometre, are likely to have been tsunamigenic.<\/p>\n

As the Google Earth image above shows, the banks of Harrison Lake are populated, meaning that any future event could have serious consequences.  Interestingly, Hughes et al.<\/em> (2020)<\/a> found that there is significant bulging at the base of Mount Breakenridge, “indicating that the slope continues to slowly deform and could be the site of a future landslide.<\/em>”  This clearly needs further investigation.<\/p>\n

Understanding past landslides into lakes is a key to understanding future hazard.  This study provides a really useful insight into the nature of previous rockslope failures into Lake Harrison.  It would now be really interesting to see a model of the resultant tsunamis and also to date the landslide events.<\/p>\n

.<\/p>\n

Quickslide 1:The duel hydroelectric landslides in Vietnam<\/h4>\n

Rescuers have now recovered the 13 bodies of the soldiers killed by the second of the two landslides associated with the Rao Trang 3 hydroelectric scheme in Vietnam<\/a>.  That these people had been sent to rescue the vicims of the earlier landslide feels particularly poignant.<\/p>\n

.<\/p>\n

Quickslide 2: A nice landslide video from Costa Rica<\/h4>\n

With thanks to Tom Hodgson, there is a nice video of a large roadside landslide in Costa Rica on the CRHoy website<\/a>.  The landslide, which was triggered by heavy rainfall, occurred on the South Interamerican highway.<\/p>\n

.<\/p>\n

Reference<\/h4>\n

Hughes, K.E., Geertsema, M., Kwoll, E. et al.<\/i> 2020. Previously undiscovered landslide deposits in Harrison Lake, British Columbia, Canada<\/a>. Landslides<\/i> . https:\/\/doi.org\/10.1007\/s10346-020-01514-3.<\/p>\n","protected":false},"excerpt":{"rendered":"

Harrison Lake: a nice paper in the journal Landslides (Hughes et al 2020) describes newly discovered, large, ancient landslide deposits in Canada. The two largest landslides would have been tsunamigenic. <\/p>\n","protected":false},"author":22,"featured_media":35272,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[544],"tags":[4,469,31,725,192,17,128],"class_list":["post-35269","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-review-of-a-paper","tag-canada","tag-featured","tag-lake","tag-north-america","tag-paper","tag-research","tag-tsunami"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/35269","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=35269"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/35269\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/35272"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=35269"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=35269"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=35269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}