11 September 2015
Weare Cliffs in Dorset
Earlier this week I posted about an ongoing landslide problem at on the Isle of Portland in Dorset, southern England, in which a progressive slope failure is causing repeated rockfalls and the development of tension cracks and ground disturbance. The coastal footpath has had to be rerouted, and members of the public are being warned to keep away. This morning several news agencies in the UK (e.g. the Daily Mail) are running with a video of the collapse of a section of cliff at Weare Cliffs:
Of course as this is the Daily Mail this is “the terrifying moment a cliff face collapses and disappears in a huge cloud of dust”. However, the article does provide some useful background. The video was collected by Sam Haskins. The Daily Mail article notes that:-
Mr Haskins, who was on a walk with his girlfriend, Bethany, said he had decided to visit the area as there had been a number of reports that the footpath had started to break away. ‘We’d heard there had been several small rock falls over the last few days and there were very large cracks appearing in the path and cliff face,’ he said.
My interpretation is that this is a rockfall at the front of the much larger progressively failing landslide block. As the topple develops (see image below) there is considerable rockfall activity. The block fragments after the collapse event.