![\"Taku](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2020\/12\/20_12-Taku-River-1.jpg\")
The landslide on the Taku Rover in British Columbia. Image by Darryl Keith Tait, posted to Facebook.<\/a><\/p><\/div>\n .<\/p>\n This appears to be a large rock slope failure, with a substantial mass perhaps detaching from high on the slope.\u00a0 If so, this mass has then triggered the failure of face of the slope below.\u00a0 The mass was in free-fall for a considerable distance – on impact with the valley floor it has instantaneously fragmented to create an avalanche with a long run out and considerable dispersion.\u00a0 There is also a large volume of scree at the foot of the slope, suggesting multiple smaller failures after the main collapse.<\/p>\n The videos also seem to show that the landslide deposit has lobate structures at the margins, which seem to form during late stage sliding across frozen surfaces, and hummocky mounds within the landslide mass.<\/p>\n Hig pointed out to me that the Facebook postings give some indication of the timing of the event.\u00a0 On 24 December 2020 at 19:50 UTC a M=2.9 earthquake was recorded very close to this location<\/a>.\u00a0 It is very likely that this is the record of the landslide itself – the magnitude is about right for a rock slope failure of this scale, and of course a free-falling mass is going to have generated a really substantial release of energy.<\/p>\n Secondly, downstream (and across the border into Alaska) on the Taku River there is a USGS gauging station<\/a>.\u00a0 This shows a really interesting spike in water temperature and in turbidity late on 24 December and early on 25 December.\u00a0 This is the graph of water temperature for example:-<\/p>\n The spike in water temperature on the Taku River, downstream of the landslide. Data from the USGS<\/a>.<\/p><\/div>\n .<\/p>\n It is reasonable to hypothesise that these anomalies may be the signal from the impact of the landslide on the river.<\/p>\n At this time of year it is very difficult to obtain satellite imagery of this area, and of course the deposit may become covered by snow.\u00a0 This is another site that we will probably need to wait until the Spring before we can obtain a better understanding.<\/p>\n![\"Taku](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2020\/12\/20_12-Taku-River-2.jpg\")
Acknowledgement<\/h4>\n