{"id":17297,"date":"2016-01-02T10:39:01","date_gmt":"2016-01-02T10:39:01","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=17297"},"modified":"2016-01-02T10:39:01","modified_gmt":"2016-01-02T10:39:01","slug":"tyndall-glacier-landslide-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2016\/01\/02\/tyndall-glacier-landslide-1\/","title":{"rendered":"The Tyndall Glacier landslide in Alaska: the largest recorded non-volcanic landslide in North America"},"content":{"rendered":"
The Tyndall Glacier landslide in Alaska<\/h5>\n

An interesting story at the 2015 Fall meeting of AGU<\/a> last month was the announcement by Colin Stark and Goran Ekstrom<\/a> that they had detected an enormous landslide in Alaska, which I am terming here the Tyndall Glacier landslide.\u00a0 As regular readers know, Stark and Ekstrom have pioneered the use of seismic waves<\/a> to detect very large landslides, with remarkable success.\u00a0 The Tyndall Glacier landslide occurred at about 8:19 pm local time on 17th October 2015 at the toe of the Tyndall Glacier.\u00a0 The landslide is enormous – Stark and Ekstrom estimate from the seismic data that it had a mass of about 180 million tonnes, which would give a volume in the order of 72 million cubic metres.\u00a0 The landslide flowed into Taan Fjord, triggering a localised tsunami that was detected 155 km away, according to the Lamont-Doherty press release<\/a>.<\/p>\n

Having detected the Tyndall Glacier landslide, Stark and Ekstrom located it with a very high resolution satellite image, which Lamont-Doherty have included in their press release<\/a>:<\/p>\n

\"Tyndall<\/a>

The 180 million tonne Tyndall Glacier landslide (NSF Polar Geospatial Center)<\/p><\/div>\n

.<\/p>\n

Note the large source area on the left side of the image, the presence of debris on the toe of the glacier, and the sediment charged water of the fjord.\u00a0 Most of the volume of the landslide must now be on the bed of the Taan Fjord.<\/p>\n

The location of the landslide at the toe of the glacier is fascinating.\u00a0 As noted in the press release:<\/p>\n

In the case of the Taan Fjord landslide, the Tyndall glacier\u2019s retreat from the edge of Icy Bay in 1961 to its current location more than 17 kilometers up the fiord removed buttressing in the valley, leaving the weak rock on the valley wall prone to collapse, Ekstr\u00f6m said. The entire valley was once filled with ice as much as 400 meters high, but as the glacier retreated, the ice thinned.<\/p><\/blockquote>\n

This mechanism of glacial debutressing has long been discussed by landslide scientist, and this appears to be a very clear example of the process.\u00a0 Given that the retreat of the glacier is being driven by the very rapid warming in the high latitudes, this is likely to be a response to global warming.<\/p>\n

The press release also includes a before and after image of the tsunami triggered by the Tyndall Glacier landslide:<\/p>\n

\"Tyndall<\/a>

An island in Taan Fiord, about 10 km from the landslide, shown by satellite in 2014 (left) and a few days after the landslide and tsunami (right). (GeoEye, Colin Stark)<\/p><\/div>\n

.<\/p>\n

The waves triggered by the Tyndall Glacier landslide was clearly both large and very energetic to have caused this level of change.\u00a0 There is no doubt that this is an event that needs detailed investigation in the Spring.\u00a0 We can learn a great deal about both large landslides and landslide tsumani genesis from this event.<\/p>\n

Finally, for now, at the time of the Bingham Canyon landslide<\/a> in Utah we compiled a list of the largest known non-volcanic landslides in North America<\/a>:<\/p>\n