1 June 2020
Eastchurch – a coastal landslide in Kent, SE England
Posted by Dave Petley
Eastchurch – a coastal landslide in Kent, SE England
Over the weekend the newspapers in the UK have been reporting two coastal landslides that occurred at Eastchurch on the Isle of Sheppey in Kent. These two landslides, which occurred at the same site, have damaged a house. The first failure occurred at 10 pm on Friday 29 May 2020:-
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This is quite an interesting landslide, with an unusual linear geometry in the rear scarp, similar to a wedge. The Isle of Sheppey consists mainly of London Clay, which is well known for the presence of fissures and joints.
Over the weekend the situation deteriorated substantially, and on Sunday 1 June 2020 a further substantial landslide occurred, causing damage to the house closest to the cliff:-
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The site of the landslide is 51.418, 0.873, as shown below. I have marked the rear scarp of the second landslide at Eastchurch:-
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As the Google Earth image shows, this section of coast is highly landslide-prone. Indeed, the Isle of Sheppey is well-known for its coastal landslides in the London Clay. However, there are two aspects of this event that are quite surprising to me. The first is that the slide has occurred in the middle of a spell of exceptionally dry weather – indeed this has been the sunniest Spring on record and parts of the UK have recorded their driest Spring on record too. Perhaps this slide was associated with dessication rather than high pore water pressures? But second, the images after the landslide yesterday seem to show a great deal of water in the rear scarp of the landslide:-
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It is not clear to me as to the source of this water, although it could be that the failure has ruptured a pipe?
It goes without saying that this is a devastating landslide for the occupants of the house. In general, UK house insurance does not cover damage caused by landslides or by coastal erosion.
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On reflection 1: too good to be true?
Various news outlets report a miracle recovery of a newborn baby buried in a landslide in Northern India. The baby appears to be thriving in hospital, but the idea that a baby could survive burial in a landslide without any protection is surprising.
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On reflection 2: 50 years after Yungay
Yesterday was the 50th anniversary of the devastating landslide at Yungay and Ranrahirca in Peru, caused by a seismically triggered landslide from Mount Huasaran.
I hope the residents of that house have been saving their pennies for a new one far from the coast – it was always going to end up in the sea …
Eastchurch: I can see a ‘bakers dozen’ properties within ~50 year downfall zone. If ponded water was pore rather than piped, land-drains may double that, but re-location may be the only solution…
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Given the historically low rainfall / high sunshine in the UK, the water presumably is from a broken water main?
Kent Online gave the name of the house as”Cliffhanger” it’s now “Undercliffe” !
The incidence that the increase in the sea level, the waves and the variation of the water table may have cannotbe ruled out. https://www.dw.com/es/mar-creciente-cuando-desaparezcan-las-costas/av-53694407
Sadly I doesn’t need to rain to make the cliffs wet as the sea when at high tide hits the foot of the cliff. Not only that but when it hot the clay drys and cracks at the top.
Has anyone considered that this could have been caused by an underground badly maintained leaking pipe effectively causing a sink hole?