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.

Sunday, 26 September 2010

Images of yesterday's landslide-induced train incidents

First, an apology in advance.  I am just en route to Chengdu in China, where I will stay until Saturday.  Whilst this provides an opportunity to return to Beichuan, which will be very interesting in the context of the rainfall-induced landslides this summer, it presents some other challenges.  The most serious of these is that Blogger is blocked by the Great Firewall of China, so I will not be able to access it to make posts.  So if it all goes quiet for the next few days, please accept my apologies.  I should be able to post again on Saturday.

Anyway, in the meantime thanks to various people for highlighting photos of the various landslide-related train incidents over the last 48 hours.  It now appears that New Zealand on its own experienced two incidents; in addition to the one at Manawatu Gorge there was also an incident at Taumaranui.  There were no injuries in either case.

In terms of the Manawatu Gorge incident, has a pretty spectacular set of images:

Meanwhile, there are also some images of the incident in India available on The Hindu website here.  Unfortunately, at the time of writing their site is down, but I managed to access it last night. Hopefully you will have more luck!

Saturday, 25 September 2010

Three landslide-induced railway incidents in a single day

News today of three different incidents from around the world:
1. New Zealand
NZ Herald reports that a milk train hit a landslide in Manawatu Gorge.  Fortunately there were no injuries, or even a need to cry over spilt milk...

Friday, 24 September 2010

Remarkable NASA imagery of catastrophic flooding around Manchhar Lake in Pakistan

NASA have provided the most dramatic evidence yet of the catastrophic floods that are occurring around Manchhar (Manchar) Lake in Pakistan (see my post yesterday on this issue).  This image was captured by the ALI instrument on 18th September:

Thursday, 23 September 2010

Pakistan flood update

The Pakistan flood crisis drags slowly on, and probably has at least a month to go before the waters fully recede.  Although the news coverage of the event is now little more than a drumbeat in the background, huge numbers of people are still being affected for the first time by this event.  The current crisis is focused on Mancchar Lake, which has been the destination of the waters that have travelled down the "ghost" parallel water course to the west of the main Indus channel, as shown very clearly by this NASA image:

Tuesday, 21 September 2010

Tangjiashan again - and a possible new Chinese flowslide

Back in 2008 I dedicated a great deal of space on this blog to the extraordinary efforts by the Chinese Army to draining the landslide lake at Tangjiashan, just above the town of Beichuan, which was created by the May 2008 Wenchuan Earthquake. 

 These efforts were ultimately successful, but in my visit to the site in Spring 2009 it was clear that a threat remained at the site in the form of another block of material that was showing signs of deformation. Over the last few days this area has received very high levels of rainfall.  Yesterday, Xinhua reported that a 300,000 cubic metre block has detached from the scarp above the barrier, and blocked the river to a depth of 10 metres:

"More than 6,200 residents were relocated Tuesday as torrential rains pounded Beichuan Qiang Autonomous County in southwest China's Sichuan Province, local authorities said Tuesday...Some 300,000 cubic meters of debris brought by the landslide caused a dam, blocking the lake's outlet. The dam's lowest point is 10 meters higher than the present water level, the statement said.  Debris still continue to come down from the hills, and if there were more rains, then the lake level would further rise, threatening the lives of people in nearby townships.The rains had disrupted the normal life of 58,000 local residents in the county, causing huge economic losses, the statement said."

China is well-versed in dealing with these hazards, but given the magnitude of the destruction in the Beichuan area, such events must cause great heart-ache.

It is clear that the elevated level of landslide activity in the aftermath of the landslide is a major issue.  I am travelling to Chengdu on Sunday, so will see whether I can ascertain more information about these issues.

Meanwhile, Bloomberg reports a probable flowslide failure in a tin mine in Guangdong yesterday:

Zijin Mining Group Co. said a dam built to hold tin-mining waste collapsed in China’s Guangdong province following torrential rain, less than three months after one of its copper mines leaked toxic waste into a river.About 60 centimeters (24 inches) of rain from Typhoon Fanapi and mud and rock slides triggered the accident at the company’s Yinyan tin mine at about 10 a.m. local time today, Shanghang, Fujian province-based Zijin said in a statement. 

China has been impacted by a series of these events in recent years, including one that caused multiple fatalities in 2008.  There appears to be a strong need to improve the safety of these facilities before another major accident occurs.

Gifts and Perils of Landslides

Ken Hewitt has written a wonderful article for Scientific American entitled "Gifts and Perils of Landslides", in which he examines the inter-relationship between the development of society and the occurrence of landslides in the Upper Indus valleys.  Ken is the guru of high mountain landslides in Pakistan, having spent many field seasons mapping rock avalanche deposits in the remote upper valleys of the Hindu Kush.  The article is available online at the following link:

Monday, 20 September 2010

Landslides in Art Part 7 - Jennifer Williams

Regular readers will know that I occasionally highlight a piece of art featuring landslides.  This is usually a piece of visual art (such as this and this), but occasionally it is a song or even an installation.  This time I thought I'd feature a piece of art by the American artist Jennifer Williams, who paints environmentally-orientated pieces using acrylic on birch panels.  Jennifer works mostly in the Pacific Northwest, where both the landscape and the sky is large and colourful.  This is reflected in her portfolio of work, which resonates strongly through its depictions of the landscape of hazards. 

Sunday, 19 September 2010

Saturday, 18 September 2010

Images of the Darfield (Canterbury) earthquake fault rupture

Yesterday I was exceptionally fortunate to be able to spend the morning looking at the surface expression of the fault responsible for the Darfield earthquake, which hit the Canterbury plains area of New Zealand a fortnight ago.  I was kindly guided around by Russ Van Dissen of GNS Science, and the visit was organised by Chris Massey, also of GNS - so many thanks to them.  This GNS map shows the surface expression of the fault across the Canterbury Plain:

Tuesday, 14 September 2010

Road failure video from Thailand

Thanks to my former student Kurtis Garbutt for the heads up on this one.  The video below shows the progressive development of a road in Thailand.  I suspect that this initiated as a culvert failure, with multiple collapses due to undercutting:

The final frames of the video show an overview of the site.  Check out where the people are standing!

As an aside, Kurtis also runs a very interesting blog on natural hazards - take a look.  It is a very useful resource with a scope that goes way beyond my site.

Saturday, 11 September 2010

Pakistan floods - the extraordinary duration of the elevated water levels

The floods in Pakistan may have faded from the headlines in Europe, but unfortunately the impact continues, even though the rainfall events that caused them occurred more than a month ago.  The most dramatic illustration of this is a set of satellite images collected by NASA using the MODIS instrument.

This is an image of the area around Sukkur taken on 7th July, before the rainfall event that initiated the disaster:

Friday, 10 September 2010

Ruapehu lahar information

One of the many highlights of the splendid IAEG Congress in Auckland this week was a talk by GNS geologist Chris Massey on the 18th March 2007 lahar at Mount Ruapehu on North Island.  The lahar occurred as a result of the failure of a tephra wall holding back the crater lake at the summit, and is shown by this NASA image:

Italian debris flood video

Thanks to Ivan Montanari for highlighting this one.  Youtube has an extraordinary video of a debris flood that appears to have occurred yesterday at Atrani on the Amalfi Coast in Italy:

The video makes a slowish start, so keep watching.  This is the first debris flow of cars that I have seen on video...!  This is a Google Earth perspective image of Atrani:

I guess it is not hard to see how very heavy rainfall, or another hydrological event in the catchment, can lead to such an event.

Thursday, 9 September 2010

A round up of intersting events and documents in the world of landslides and slopes

1. Please vote for a slope monitoring project
One of the recurrent themes of the IAEH Congress is the growing importance of slope monitoring techniques to provide warning of the development of failure.  One of the most exciting projects is the ALARMS project, led by Prof. Neil Dixon at Loughborough University, which is developing techniques that use acoustic emissions to monitor slope movements.  The project has been entered into an Enterprise competition at Loughborough University, which will be decided by a free vote.  So, please can you visit this page: and vote for the Alarms project.  It would be a very worthy winner of the prize.

2. Manual on Engineering Geological Practice in Hong Kong
On behalf of the Hong Kong Geotechnical Engineering Office, AECOM have produced a new manual on engineering geological practice in Hong Kong.  Unsurprisingly, it has a strong slopes and landslide component, and it is relevant in areas outside of Hong Kong itself.  This can be downloaded as a pdf for free here.  I recommend it - I think that it will become a very useful guide and reference text.

3. 11th Symposium on Landslides (ISL)
The big four yearly slopes event is the ISL, which was last held in Xian, China.  The next event is in June 2012, and will be held in Banff, Alberta Canada.  This should be a fantastic event in a wonderful location.  The meeting now has a website, and the call for abstracts has been released, with submissions due by 15th April 2011.  Get writing!

4. Slope Stability 2011
In September 2011, Canada will also host a conference on rock slope stability, with a strong emphasis on the mining industry.  This event, which will be held in Vancouver, will be a great opportunity for academics and practitioners to interact.  The site has a website, and again a call for abstracts is out, with a deadline of 7th January 2011.

IAEG presentation and paper on Attabad

Today I presented an invited paper at the 11th Congress of the IAEG in Auckland, New Zealand on the topic of landslide hazards along the Himalayan Arc.  This paper starts by looking at global and regional landslide hazard before presenting the state of play at Attabad.  As usual, I have uploaded the PowerPoint file to Authorstream, such that you should be able to both view and download it below:

The written paper has been published in the conference proceedings.  I do not have a pdf of the actual printed version but I do have one of the final manuscript.  I am working on putting that online, so watch this space.

A pdf of the paper itself is available here:

Note that this paper contains a map of global landslide losses in terms of fatalities and some data both for global losses and for those in the Himalaya. 

Note that the typeset format is slightly different from that of the actual published paper, but the content is the same.  The reference to the paper is:
Petley, D.N., Rosser, N.J., Karim, D., Wali, S., Ali, N., Nasab, N. and Shaban, K. 2010. Non-seismic landslide hazards along the Himlayan Arc.  In: Williams, A.L., Pinches, G.M., Chin, C.Y., McMorran, T.J. and Massey, C.I. (eds) Geologically Active.  CRC Press, London, pp. 143-154.

Friday, 3 September 2010

Updated: The New Zealand earthquake

Bizarrely, I am currently sitting in the QANTAS lounge at Sydney Airport waiting for a flight to New Zealand, where the IAEG Congress starts on Monday.  The theme of the conference is "Geologically Active"...

So, what do we know about the earthquake so far.  The best source of information is the Geonet site - - which puts seismic data online in real time.  They are reporting that the earthquake occurred at 4:35 am local time 30 km west of Christchurch at a depth of (now updated to) 10 km.  The reported magnitude is (now updated to) 7.1 - USGS is reporting 7.0, but this is probably a moment magnitude.  This is the isoseismal map from Geonet:

This suggests that some damage in the Christchurch area is likely, which seems to be confirmed by the initial news reports.  Hopefully the timing of the earthquake, and the high level of preparation for earthquakes in New Zealand, will mean that casualties will be light and damage manageable.  Perhaps the most interesting data at this stage is the map of locations in which people have reported they felt the earthquake.  This looks like this at the time of writing.  The dark orange dots represent an intensity sufficiently large to cause significant damage:

GEONET shake map

There are no reports of landslides as yet, but given the proximity of the Southern Alps some landslides are likely:

More later.

August fatal landslide data

The end of the month marks the point at which I post the accumulated totals for fatal landslides, based upon the global fatal landslide database that I maintain.  The raw figures for August are stark.  The total number of fatal landslides recorded in the month was 71, resulting in 2,740 fatalities.  This total is of course dominated by the Zhouqu landslide in China, which is reported to have resulted in 1,765 deaths.  (Click on read more to access the remainder of this post).

Thursday, 2 September 2010

Another large landslide in China

China has today suffered another large landslide event.  Xinhua reports that a slide happened at 10:20 pm on Wednesday in the village of Wama in Longyang District, Yunnan, leaving 8 people dead and 40 missing.  Xinhua have this image of the slide:

As far as I can tell, this is the location:

Unfortunately the Google Earth image for this area is poor, but there is a report on a small hydro-electric scheme at this village available online here.  I should add that I am not suggesting that the HEP scheme was responsible for the slide.  This article on recent permission for logging in the area is also interesting. 

Wednesday, 1 September 2010

The latest NASA image of Attabad

NASA have released another spectacular satellite image of the Attabad dam and lake.  In the article they focus on the upstream end of the lake: