8 June 2020
A further significant failure at the site of the Alta quick clay landslide
It appears that this is another major failure that is retrogressive from the events of Wednesday. This landslide is notable for the destruction of the road. Note that the landslide scar is almost completely evacuated – i.e. there is no landslide debris in sight – suggesting that this was once again a highly mobile event. The iTromso website has an image taken from a different angle:-
This image of the landslide scar shows the thick layer of marine silts and clays that is responsible for the high mobility of these landslides.
I suspect that the focus now will be on securing the road, which is clearly an important transport link for people living in this area. I hope that in due course some bathymetry work might be undertaken offshore from the landslide. It would be extremely interesting to understand the mobility of the landslide on the seabed.
On reflection 1: Heavy rainfall causes landslides in Hong Kong
Heavy rainfall yesterday caused landslides in the Sai Kung, Shatin, and Tai Po areas of Hong Kong yesterday. News reports indicate that 24 landslides have been observed.
On reflection 2: Coseismic landslides in Kamikochi, Japan
An ongoing swarm of small earthquakes is causing landslides and rockfalls in the Kamikochi area of Japan. The Asahi Shimbun has some good images.