Amazing cliff collapse caught on camera

Last updated: 10/10/2011 Add to My Bookmarks Subscribe

An amazing cliff collapse captured on camera by a Cornwall Council engineer has become an internet sensation.

On Monday 19 September Cornwall Council received notification from Coast Guards and Police that a jogger on the coastal footpath near Hell’s Mouth on Cornwall’s north coast had reported a large crack in the path.

Cornwall Council’s Soils & Materials Engineer Richard Hocking met with the local Countryside Officer on site later that morning. Having assessed the situation a decision was made to divert the path inland away from the crack. This was carried out by The National Trust (landowners) on Tuesday 20 September 2011. The site was re-inspected on Wednesday to confirm that the alignment of the diversion was satisfactory.

On Thursday 22 September, the Countryside Officer contacted Richard to say that the failure had progressed and that large tension cracks were opening up; Richard went down to look at the situation and was satisfied that the diversion remained safe.

On Friday 23 September Richard went to take another look following reports of material falling from the cliff throughout that day. By around 4.30 pm there were several visitors watching the scene.

Richard explains: “I happened to have my digital camera with me, so out of interest I put it on ‘video mode’ and started shooting. Unfortunately this was the first time I’d used it in this mode and was unfamiliar with the settings, hence the poor quality. At about 4.50 pm the large cliff fall occurred, which I captured on camera.”

Richard went back to the site over the weekend and noted a substantial further fall had occurred and that a further tension crack inland of the failure had appeared within about 7 or 8 metres from the diversion, and the footpath was redirected further inland.

Richard says: “This was the most spectacular event I have seen in my 28 years as a geologist and, realising the uniqueness of the situation, my colleague and I decided to try and distribute it to the geological fraternity. As the file size was too large for e-mailing, my colleague managed to compress it and eventually upload the footage to YouTube on Monday 3 October; everything was quiet until the site starting receiving a phenomenal number of hits this past weekend.”

“With regards the failure itself, this is a massive progressive rock failure, probably caused by a deep-seated inclined fault plane on which the rock mass slid (a Plane Failure), although due to the volume of debris the original fault is obscured. We estimated that a couple of hundred thousand tonnes of material collapsed into the sea. These failures are not uncommon along this section of coast, although this is one of the most dramatic ones in recent years and was probably caused through weathering and fluctuating groundwater pressures.”

Story posted 10 October 2011