This blog provides a commentary on landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings. The blog is written on a personal basis by Dave Petley, who is the Wilson Professor of Hazard and Risk in the Department of Geography at Durham University in the United Kingdom.

This blog is a personal project that does not seek to represent Durham University.

Wednesday, 27 February 2013

Landslides in Art Part 17: Decisive Moment by Chen Po-I

This is the latest of my occasional series of posts about the depiction of landslides in art.  Part 16 can be found here.

Chen Po-I is an unusual artist. He trained to Masters Level in Ocean Engineering at National Cheng Kung University in Taiwan before turning to photography.  He is now a celebrated photographic artist with a long list of exhibitions.  He has a Flickr page depicting some of his work here.
His current exhibition is at the Fotoaura Institute of Photography in Tainan in Taiwan (there is a brief write-up of it in the Taipei Times).  The works are interesting and challenging.  In 2009 Typhoon Morakot struck Taiwan, bringing extremely heavy rainfall that triggered widespread landslides and debris flows.  Chen Po-I has collected a series of images of the destruction that the debris flows caused, focusing primarily on the marks left on walls by the flows:

Marakot 2: Photo courtesy of Fotoaura Institute of Photography

Tuesday, 26 February 2013

A new, free landslide resource - Community based landslide risk reduction: Managing disasters in small steps

Over at Bristol University in southwest England Malcolm Anderson and Liz Holcombe have been doing some really interesting work over the last few years in the Caribbean, seeking to fins ways to enhance resilience to landslides.  This has been a highly successful programme that in many ways has not received the recognition that it deserves.  This work has culminated in a new World Bank publication entitled 'Community based landslide risk reduction: Managing disasters in small steps':


Read the rest of this post at the AGU home of this blog by clicking here

Monday, 25 February 2013

Rockfalls shaking a volcanic lava dome apart (including a dramatic video)

James Reynolds is a video maker based in Hong Kong who specializes in collecting footage of extreme natural hazard events.  In the last few days he has been in Indonesia filming the ongoing volcanic event that is affecting Paluweh Volcano in Indonesia.  This volcano is currently undergoing a phase of lava dome growth, which over the last few weeks has also been accompanied by eruption events that have generated ash plumes,  As is usually the case, this is accompanied by regular seismic events.  During his visit to the volcano James caught this amazing footage of the lava dome being shaken by these seismic events, generating rockfalls across he whole of the mass. 

Read the remainder of this post on the AGU home of this blog by clicking here

Friday, 22 February 2013

The Bitter Springs landslide in Arizona, USA

This week a landslide has occurred on US89 south of the town of Page in the vicinity of Bitter Springs in Arizona, USA.  Whilst this was initially reported to be a sinkhole, this is very clearly a reactivation of an ancient landslide.  It has caused extensive damage to the road, which is now closed:

Others in the blogosphere have covered this landslide much better than I ever could, so here is a list of useful links (and thanks to several people who have helped in putting this together):

Click here to read the rest of this post on the AGU home of this blog

Thursday, 21 February 2013

Whilst the focus of this blog over the last week has been the remarkable Hatfield Stainforth landslide (for info the lack of updates is because the flow of information from the site has now dried up), two other landslides in coal mines in Asia have claimed lives:

1. A mining-related landslide in Guizhou Province
At 11 am on Monday a large rockfall from a steep cliff that was being undermined by a small-scale coal mine in Longchang township, in Kaili city, Guihou Province, China buried five people, including two children.  Whilst the remains of the victims have not been recovered, it is now accepted that all of the victims were killed.  Interestingly, this landslide has been extensively covered in the media in China, which has released very high quality photos of the site.  The best gallery is in the online version of the UK newspaper of the Daily Mail.

View the rest of this post on the AGU home of this blog by clicking here

Tuesday, 19 February 2013

More images of the Hatfield Stainforth coal mine landslide

Over the last few days a number of people have very kindly provided images of aspects of the Hatfield Stainforth coal mine landslide near to Doncaster in northern England.  Before we get into that, a few people have asked about the nature of the mine - in this case the mine is an underground pit, with the coal and spoil being hoisted to the surface.  The landslide has occurred on a heap of spoil from the mine workings.
So, on to the images.  Let's start with a couple of the site before the landslide occurred. Darren Hedges has provided this image of the site before the landslide - this was taken in September 2012, so probably represents the site in its pre-landslide state rather well:

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Friday, 15 February 2013

New aerial photos of the Hatfield Stainforth colliery landslide

More information is now emerging about the Hatfield Stainforth landslide colliery landslide near to Doncaster in England.  First, to help understand the timescale of the development of the site, this image has been provided by Richard Aspinall, a resident of the Stanforth area, before the spoil heap was developed:
Image copyright of Richard Aspinall. For educational and not for profit use only
The image was taken in October 2009, which demonstrates that the tip that has failed is very recent.  It also shows that there was no slope present before the tip was created.

Read the rest of this post on the AGU home of this blog by clicking here.

Thursday, 14 February 2013

The geology and a possible mechanism of the Hatfield Stainforth colliery landslide

Unfortunately, overnight no new images have appeared of the Hatfield Stainforth landslide, so it is difficult to know whether the landslide has now stopped moving.  The morphology of the landslide continues to suggest to me that this is a bearing capacity failure.  I have taken a quick look at the excellent BGS Geology of Britain Viewer, which produces the following map (I have marked the approximate location of the colliery at which the landslide at occurred):
copyright BGS:
The map shows that underlying the location of the spoil tip is a layer of alluvium - basically soft sediments such as sands and gravels deposited by ancient rivers.  These are comparatively weak materials, especially when wet.  So, my hypothesis is that the weight of the spoil tip has caused the development of a failure through these materials, which has then generated a landslide with a rotational geometry.  The sketch below is my suggested interpretation, with the spoil sitting over a layer of alluvium.  The very wet weather over the last few months has led to a high groundwater level, which in turn has reduced the strength of the alluvium.  This has then failed with the geometry shown in the upper sketch - the rotational landslide has then progressively moved to generate the geometry in the bottom sketch:

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Wednesday, 13 February 2013

The Hatfield Stainforth colliery landslide - an update suggesting that it has been moving since yesterday

Two new images have become available on Twitter in the last few hours of the Hatfield Stainforth landslide near to Doncaster in NE England.  This is a fascinating landslide that is causing a huge amount of damage to the railway lines.  First, there is this image taken from further along the line:
View the rest of this post on the AGU home of this blog by clicking here

An unusual colliery landslide yesterday - Hatfield Stainforth in Northern England

In the UK there is a very high level of sensitivity about colliery landslides because of the Aberfan disaster over 40 years ago.  The result has been a huge effort to prevent and mitigate landslides associated with coal mines, such that colliery landslides are now unusual.  Thus, the very large landslide at Hatfield Stainforth on the outskirts of Doncaster is very surprising.  This may well be the largest and most significant landslide in the UK for a decade or more, even though the mainstream media has yet to catch up with it.  You will see what I mean when you see the aerial photograph released by Network Rail via Twitter last night, which says it all:
Read the rest of this post at the AGU home of this blog by clicking here

Tuesday, 12 February 2013

The full video of the Mount Dixon rock avalanche from Aoraki / Mount Cook National Park in New Zealand

A couple of weeks ago I featured the news coverage that included the video of the spectacular rock avalanche from the flanks of Mount Dixon in Aoraki / Mount Cook National Park in New Zealand.  That video was shot by a climber, Neil Wiltshire.  Over the weekend Neil very kindly dropped me a line about the event, and he has now posted the full video on Youtube.  So here it is in its full glory.  I'll post again later in the week with a full analysis, but in the meantime enjoy - it is truly astounding!

View the video on the AGU home of this blog by clicking here

Monday, 11 February 2013

The Knipe Point landslide - arguments over the cause of the failure

An a few occasions over the last few years I have blogged about the landslide at Knipe Point, near to Scarborough, in North Yorkshire.  My first post was about the initial landslide problem, then subsequently about the range of options at the site, and also about an interesting art project that is underway in one of the threatened houses.  As a reminder, Knipe Point is a collection of houses located at crest of an ancient coastal landslide in glacial till - in recent years the landslide has retrogressed (enlarged), damaging houses in the process, as the before (2002) and after (2008) Google Earth images show:

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Wednesday, 6 February 2013

Probably the largest mass movement ever recorded on video

In  this case a mass movement of ice, not rock and soil, on the Ilulissat Glacier in Western Greenland, a part of the film Chasing Ice.  It is genuinely astonishing – the volume of the collapse is apparently 7.4 cubic kilometres.

View the  rest of this post on the AGU home of this blog here.

Tuesday, 5 February 2013

Landslide oddities number 1: arresting a felon

This is the first in what I hope will be a series of posts on landslide oddities. Thanks to both Ellen Hardy and Alexandre Mathieu for their help with this one. yesterday carried the story of Cody Pettit, who stole a taxi at  kiofe point on Saturday, and set off for a joyride in Brookings, Oregon, USA.  He was spotted by a police officer, who duly gave chase.  This ended somewhat abruptly when Pettit turned onto a minor road, only to crash into a landslide that was blocking it:

Read the rest of this post on the AGU home of this blog by clicking here

Friday, 1 February 2013

Landslides and rural roads in high mountains - an example from Nepal

Accounting for changes in landslide patterns with time is very difficult.  Collecting the underlying datasets is problematic in itself (still requiring mapping by hand in most cases) and, of course, landslides result from a combination of a whole range of natural and human factors, all of which change with time.  It has been frequently postulated that one of the underlying causes of the increase in landslides in mountain areas in less developed countries is road building - indeed in a paper that I wrote with some colleagues a few years ago (Petley et al. 2007 - drop me a line if you want a copy) we proposed that inappropriately engineered road construction might account in large part for the increase in landslide impacts in Nepal over the last 20 years or so.

Read the rest of this post on the AGU home of this blog