13 May 2016
New landslide videos from the last few days, including an impressive rockfall at Mont Granier
Posted by Dave Petley
.
A large rockfall on Mont Granier
Mont Granier is located in the Chartreuse Mountains of the French Prealps. This was the site of an enormous landslide in 1248 that may have killed over a thousand people. In early January 2016 there was another substantial rock slope collapse on Mont Granier, and there has been at least one other event this year. Earlier this week, on 7th May, a further rockfall occurred, comprising a collapse of a limestone pillar. This event was captured on a good video that is now on Youtube:
.
The site of this rockfall is captured rather nicely in this video of the rockmass:
.
Not unusually, the rock mass is continuing to generate small scale rockfall activity:
.
Le Dauphine has some nice images and a write-up (in French) of this event (along with some very irritating adverts). They suggest that this rockfall was similar in scale to the event of January 2016, with a volume of about 50,000 cubic metres, although other reports suggest that the event in January was much larger, with a volume of about 170,000 cubic metres.
A landslide at Swimmer’s Delight in Humboldt County, California
A less spectacular, but nonetheless interesting landslide was also captured at Swimmer’s Delight in Van Duzen County Park, Humboldt County in California last week. The Lost Coast Outpost has a nice write up of this event:
A tower of rock and earth crashed into the Van Duzen River at one of Humboldt County’s most popular swimming holes last week. A group of locals were able to capture the moment on their smartphones as they ate lunch on the riverbank of Swimmer’s Delight at Van Duzen County Park in Fortuna last Monday.
The video is quite neat, especially the final, somewhat dynamic, event:
.
I was relieved to see that none of the drinks were spilled.
Someday it will be a standard feature for phones to issue a powerful electric shock when someone tries to shoot video in portrait orientation.
A video of the aftermath working its way down the mountain slopes:
http://france3-regions.francetvinfo.fr/alpes/chapareillan-isere-la-route-du-col-du-granier-fermee-apres-une-impressionnante-coulee-997295.html
It is a slow lahar!