1 December 2012
Further landslide movement in Dorset, England
Posted by Dave Petley
In my post yesterday I noted that:
” …deep groundwater levels will now be rising, so don’t be at all surprised if there are reports of larger landslide movements over the next few months. Places such as Dorset and the Isle of Wight, where there are large coastal landslide systems, will be particularly vulnerable.”
And sure enough, the BBC website today has an article that starts:
“A section of coastline in Dorset has been cordoned off after a crack was seen in a cliff. Coastguards called to Charmouth on Wednesday put up warning signs and Dorset County Council is considering if further action is needed.”
Don’t be too impressed – that deeper landslide systems will become more active was inevitable, so this was an easy call to make. Charmouth is a well-known landslide hotspot, as the Google Earth image below shows. Indeed, it is one of the places that all landslide scientists should visit:
. To the west of the town is the famous Black Ven landslide complex:
To the east is the Stonebarrow landslide:
At the moment it is not at all clear where the recently reported movement has occurred, or indeed the nature of the crack that has opened up. I suspect we’ll see more such reports in the next few months.
I’m interested in current thought on the lag between high rainfall events/winters and the onset of major landslide event. Some work I did on the Dorset Coast some years ago indicated it could take as long as a year or two for landslide to really get underway. I think Denys Brunsden has also found a similar lag. What’s the latest thinking on lag time.