14 October 2016

Aletsch landslide: significant acceleration of movement

Posted by dr-dave

Aletsch landslide

The movement rate of the Aletsch landslide in Switzerland, which I highlighted last week, has accelerated significantly in the last few days.  This is a very large rockslope failure – the estimated volume is up to 200 million cubic metres – at Moosfluh in the Riederalp, Canton du Valais, above the left flank of the Aletsch Glacier.  Jens, a reader of the blog, kindly highlighted a report about the landslide, in German, on the Swiss SRF News website.  This film should be visible below:

A translation of the key part of the report is as follows:

“The situation around the massive terrain movements on the Aletsch glacier has intensified in recent days. The fissures open up to 80 centimeters – dailyLarge cracks in the ground – rocks that are slipping more and more: The hiking trails on the edge of the Aletsch Glacier are currently restricted areas…Geologists have been monitoring it around the clock for weeks.

The film shows the very extensive cracking that has now developed across the landscape:

Aletsch landslide

Extensive ground cracking in the extensional component of the Aletsch landslide in Switzerland, via SRF

The report indicates that the landslide is moving faster than had been anticipated  The report quotes the geologist from the canton:

“Everything is moving very fast, I have never seen such speeds,” says Raphaël Mayoraz.

An interesting dimension of this landslide is that a gondola the Moosfluhbahn – it even has its own Facebook Page – crosses the slope close to the landslide, constructed just last year.  The upper station of the gondola was designed to move with the slope up to 11 meters horizontally and 9 meters vertically.  At present the gondola remains open, and there does not seem to be major concern with regard to its safety..

The evolution of the slope will be fascinating to observe over the coming weeks.

Previous posts of interest: