11 April 2016
The Tyndall Glacier landslide: images from from the University of Alaska Fairbanks
On 17th October 2015 the huge Tyndall Glacier landslide occurred on the flanks of Taan Fjord in Icy Bay in Alaska. I featured this landslide, which was detected via the seismic detection system developed by Goran Ekstrom and Colin Stark, in a blog post at the start of the year. This is the largest recorded landslide in North America, with a volume of about 72 million cubic metres and a mass of about 180 million tonnes. The landslide generated a large tsunami that caused extensive damage along the flanks of Taan Fjord. However, until now it has not been possible to get a good impression of the impacts of this event as the area has been covered in snow.
Chris Larsen from the Geophysical Institute of the University of Alaska Fairbanks has flown along Taan Fjord, and a press release has provided two images of the site and the effects of the displacement wave. So, first, this is an image of the landslide scar:
On the right side of the image some of the damage caused by the displacement wave is visible. This is much more clear on the other image released:
The removal of trees and the topsoil as the wave traveled down the bay is clear. In the press release, Chris Laren is quoted as saying:
“It almost blows away everything in the historical record except for Lituya Bay…It’s really a unique event to have a tsunami 100 meters high.”
The press release finishes as follows:
Icy Bay and places like it will have more landslides as time goes on, Larsen said. Warmer temperatures melt more glacial ice that buttress hillsides. When the ice melts, oversteepened slopes will fail. Sometimes it takes a big rain or an earthquake to shake them down. “These megatsunamis are infrequent in the historical record but will most likely increase,” Larsen said.
We live in interesting times.