15 May 2008

The Dorset landslide revisited

Posted by Dave Petley

It is now sensible to revisit the 7th May Dorset landslide, upon which I blogged here. Now, eight days on, it is clear that there was a slight media over-reaction to this event, probably spurred by reported comments that this was the largest failure for a century. It wasn’t.

The image below from the BBC, clearly shows what actually happened. A section of cliff has collapse from the Blue Lias at the front of the landslide complex. The failure is wide but does not propagate very far inland. This is much smaller than other recent movements on this landslide complex, albeit visually dramatic from the beach. It is true that if there had been people on the beach at the time the consequences could have been serious. However, there weren’t, meaning that this is not a really significant event.

John Lock has very kindly provided two images from the Lyme Regis side, which I reproduce below. The first shows the site of the landslide before the failure, taken from the Lyme Regis side, the second shows the same site afterwards.

Of course, the interesting factors here are:
1. The way in which the media provide misleading impressions of what actually happened; and
2. The potential implications for stability upslope given the loss of the toe of this part of the complex. I am sure that the local authority will now be pretty active in assessing the latter.