Showing posts with label Landslides. Show all posts
Showing posts with label Landslides. Show all posts

Wednesday, 26 September 2012

Lessons from China (2) - Active Landslide Video

Below is a video of an active landslide in the Gansu Province of China, observed on the 13th September 2012. This slope face had reportedly been falling apart since the previous afternoon, and had resulted in the evacuation of a number of houses. At the base of the slope is a small river, and there was concern that the material could block the river and result in flooding.

You can see a number of features within the video, including large boulders bouncing and a constant (dry) flow of material.


Monday, 24 September 2012

Lessons from China (1) - Introduction

As highlighted on the GfGD blog last week, I have recently returned from the First International Symposium on New Techniques for Geohazards Research and Management in the Gansu Province of China. This conference encompassed two days of presentation relating to landslides, debris flows and management strategies followed by four days in the field, travelling 1200km by road to visit sites of major landslide activity.

The beauty and magnitude of the landscapes there was enormous, ranging from magnificent loess terraces, to sharp limestone mountains and vast sediment-laden rivers. It was, however, the raw vulnerability of communities that impacted me most - The desperate need for improved science and engineering, but an even greater need for better communication, decision making, education and understanding of how to build resilience. 

Posts about various aspects of this trip, case studies and challenges, will come in the near future. In the meantime, here are a few photos taken from the trip. Look out on Wednesday for a video of the active landslide in the final picture below.

Landslide in loess terrain (Heifangtai, Gansu Province, China)
(c) Geology for Global Development, 2012

Construction of a large debris flow channel to reduce the risk to the community at the bottom of the valley. A deadly flow killed over 1500 people in 2010.
(Zhouqu, Gansu Province, China)

(c) Geology for Global Development, 2012

An active complex landslide - with failure occurring in both the loess material and bedrock
(Gansu Province, China)

(c) Geology for Global Development, 2012

Monday, 23 July 2012

The Landslide Blog

Landslides have been in the news a lot recently, including a number of reports about landsliding in the UK and many articles about landslides across the world. For example, the BBC News recently covered the fatal landslide in Dorset, UK, reported a rise in landslides in South Asia, a mudslide in Austria, and discussed flooding and landslides in Japan. 




As highlighted previously on this blog, Dave Petley's Landslide Blog, hosted by the AGU is a fantastic place to get up-to-date information, photographs and links to media reports about the latest landslide occurrences. It's well worth putting in your favourites tab and keeping an eye on!

Monday, 2 July 2012

2012 Bududa Landslide, Eastern Uganda

It was very sad to read last week of another large landslide on the slopes of Mount Elgon, in eastern Uganda. Heavy rains resulted in a large landslide sweeping away three villages, and burying an estimated 70 people.This area of Uganda has been hit by other landslides in recent years. In March 2010 an estimated 350+ people were buried by a large landslide, and in August 2011 a landslide killed an estimated 24 people.

These articles proposed a series of measures that should be considered in order to reduce the risk of further disasters: 
1) RELOCATION: A thorough and detailed examination of the Mount Elgon area to determine the areas at greatest risk of landslides. Those at greatest risk should be relocated. The Governments plans to relocate over half a million people have proved to be slow and unrealistic, but some relocation must occur to avoid further serious tragedy. 
2) INCREASED SUSTAINABLE FARMING: Working with communities to encourage a more sustainable farming method in the region, reducing deforestation, undercutting of slopes and increasing natural drainage. There are significant concerns that over-farming on these slopes is increasing soil erosion, reducing natural anchorage and thus continually increasing the vulnerability of these slopes. 
3) ENGINEERING SOLUTIONS: Improving draining of the slopes and toe weights at the foot of particularly vulnerable slopes to increase stability. In addition some instrumental measurement of the slope condition could provide valuable information.
A holistic, multi-faceted approach is essential, as all three of the above have their challenges and limitations. Many people do not want to be relocated, as the slopes of Mount Elgon have good, fertile soil. Compulsory relocation has its challenges, and so there must also be investment in training for farmers - relating to reducing soil erosion and deforestation, and improving drainage. Possible engineering investments should also be considered. Without some form of action the images that we have seen in the past week are likely to be seen again and again.

As Dave Petley has written on The Landslide Blog, this has not been the only landslide recently. There have been significant landslides in Bangladesh and India as well, with a number of fatalities, injuries and missing people.

Tuesday, 10 January 2012

In the News: Brazil

Source: Vladimir Platonow/ABr
 Last year Brazil suffered from severe flooding and landslides, leading to what was described by many to be the 'worst natural disaster ever to befall Brazil.' Currently Brazil is back in rainy season and is again suffering from intense rain, flooding and landslides. Last week the intense rains caused a dam burst, leading to the evacuation of several thousand residents who faced the prospect of severe flooding as a result. Dam failure is always a very serious problem communities face, and the video shown within the above link hightlights why, with huge volumes of water being released.

One of the reasons the rainy season causes significant trouble in Brazil is beacuse of the poverty of many people. Poverty drives many people to inhabit the unsafe, unstable slopes surrounding cities such as Rio de Janeiro. Whilst many people know that the ground they live on is potentially lethal, they have little choice or choose to accept the risk in order to be closer to the main city, bringing food and a potential livelihood. 

Over the past year Brazil has invested significantly in measures to prepare for this year's rainy season and reduce the impacts of the rainy season - including better monitoring, forecasting and emergency evacuation procedures. The effectiveness of these measures will be evident over the coming weeks and months. In order to effectively reduce disaster risk in this area the authorities need to combine effective science and engineering with sustainable social development, community participatory approaches and effective governance and town emergency planning. Whilst it is not an easy task, it is encouraging to see how Brazil has invested in these areas over the past year - an investment which could save many lives in future rainy seasons.

Update: Since writing this post mudslides have occurred, killing 12 people (to date) - more information can be found on the BBC Website,

Monday, 19 September 2011

Earthquake in the Himalayas

An earthquake (M6.9) struck the Himalayas yesterday, impacting areas of India, Nepal, Tibet and Bhutan. Dave Petley has written two helpful blogs on his 'Landslide Blog' site that give a good insight into the geology and impacts of this earthquake. One thing he discusses is the added effect of landslides following the earthquake. As the earthquake hit at the end of the monsoon season, the ground is already quite saturated promoting ground instability, and further wet weather is due.

Thursday, 8 September 2011

Newswatch - September 2011

Newswatch is a regular round up of some of the key stories relating to the geosciences and international development. This month we look at typhoon triggered landslides, the landslides in Bulambuli (Uganda), World Water Week and the crisis in the Horn of Africa.


Typhoon Triggered Landslides 
Dave Petley's Landslide Blog - hosted by the AGU - has some remarkable pictures of a landslide in Taiwan, triggered by typhoon Namadol, with one comment suggesting the landslide had a runout of 2km. It is well worth having a look at the rest of his site also - with reports from typhoon triggered landslides in Japan also.


Mt Elgon Slopes, Uganda
Uganda Landslides
Following last month's landslide in the Bulambuli area of Uganda, there have been a few reports giving updates about the situation there. One report suggests that food aid has only just reached the 800+ households affected, due to many roads being severely affected by the heavy rains. The Uganda Red Cross has managed to distribute medicine, clothes, blankets, water purifiers, mosquito nets, jerrycans and saucepans - however the need for food has been desperate as many crops were buried by the landslide. Flooding in the area, following heavy rains, has affected a wider area with widespread flooding of pit latrines - putting people at risk of water-borne diseases such as cholera.


World Water Week
Following last week's post about World Water Week here are another couple of blogs written by those who were there. The first is on the End Water Poverty blog and the second, looking at the role of the private sector, is on the Tearfund blog. 


Horn of Africa Drought & Famine
It was welcome to see the terrible situation in the Horn of Africa raised in Prime Minister's Questions yesterday, and it is to be hoped that the political will to continue addressing this crisis is maintained. For the latest information on the situation, The Guardian publish online a weekly blog outlining the funds required and received, and further information.     

Tuesday, 30 August 2011

2011 Bulambuli Landslide, Eastern Uganda


A major landslide has affected the slopes of Mount Elgon in the Bulambuli District of Eastern Uganda. The landslide has been attributed to heavy rains in the region which is prone to large landslides. In a region hit by drought, with many requiring food aid following the lack of April-May rain, these torrential rains, flooding and landslides are a further blow for local communities. 

The landslide in Bulambuli is believed to have killed at least 24 people, including many children. An entire village is reported to have been buried in mud - which suggests that the death toll could rise as the rescue process continues. Sources suggest that further landslides are possible as heavy rains continue and one report suggested that experts had identified a 40km crack along the slopes of Mount Elgon that could put over 8000 people at risk from major landslides. It is believed that these observations were made by researchers at the University of Makerere in Uganda.

In March I wrote a report of a major landslide that had occurred a year earlier (March 2010) in Bududa, Eastern Uganda. The article highlighted the series of problems that led to the landslide occurring and made some recommendations in order to reduce the risk of future disasters. The article called for:


1) RELOCATION: A thorough and detailed examination of the Mount Elgon area to determine the areas at greatest risk of landslides. Those at greatest risk should be relocated. The Governments plans to relocate over half a million people have proved to be slow and unrealistic (as I suggested in March), but some relocation must occur to avoid further serious tragedy.

2) INCREASED SUSTAINABLE FARMING: Working with communities to encourage a more sustainable farming method in the region, reducing deforestation, undercutting of slopes and increasing natural drainage. There are significant concerns that over-farming on these slopes is increasing soil erosion, reducing natural anchorage and thus continually increasing the vulnerability of these slopes.

3) ENGINEERING SOLUTIONS: Improving draining of the slopes and toe weights at the foot of particularly vulnerable slopes to increase stability. In addition some instruments could be used to  measure the conditions of the slope, instruments such as inclinometers (to measure deviation from the vertical - i.e. if the slope is moving) and piezometers (to measure the pore fluid pressure).

Tuesday, 31 May 2011

Newswatch: Landslide Activity

Newswatch is a regular round up of some key stories relating to the geosciences in international development. Last time Newswatch examined stories relating to Geohazards, today Newswatch stays on this theme and looks at a range of landslide stories making the news (or as is often the case, not making the news)...

Source: Wikipedia
The Landslide Blog reports increasing water levels behind the Attabad landslide in Pakistan. The Attabad landslide in 2010 blocked a river and generated a lake behind it - storing large amounts of water. The release of this huge volume of water would have severe consequences, resulting in damage and deaths. Monitoring of this landslide and dam is being done, and currently water levels are being seen to rise. Rising water levels could lead to failure of the dam. The dam could also fail due to a further landslide displacing water and generating a huge wave or an earthquake causing failure. Read more about this situation on Dave Petley's Landslide Blog

Landslide Warning, Sri Lanka
Heavy rain has resulted in severe flooding and landslides, killing eight people and displacing many more (to date) in the Asian country of Sri Lanka.


Landslide Hits Orphanage in Malaysia
A week ago a landslide hit an orphanage in Malaysia, resulting in a number of fatalities. Comment on this story can be also be found on The Landslide Blog.



Monday, 23 May 2011

Resources: The Landslide Blog

The American Geophysical Union host a number of blogs, and one key blog I highly recommend is Professor Dave Petley's Landslide Blog. This blog features regular articles and photos of landslide activity across the world. Professor Petley posts reports of work he is conducting himself (e.g. in Attabad, Pakistan) and reports of landslide activity in the news - such as his most recent post (to date) looking at the Malaysian landslide that hit an orphanage. 

Landslides are a huge problem in many countries around the world, and impact a number of developing countries (for example, I wrote a post a while back on the Bududa Landslide in Uganda). Understanding more of the science behind them, the risks they pose, and measures that can sometimes be taken to reduce their frequency and impact has a very important role in global development, and disaster risk reduction. Professor Petley writes with clarity and accessibility - and makes the study of slope stability very interesting. 


Further Reading:

Thursday, 19 May 2011

Panama: Multi-Hazard Case Study

A very interesting multi-hazard case study in Panama is reported on the website of the Smithsonian Tropical Research Institute. Heavy tropical storms in December 2010 resulted in increased groundwater levels, higher pore fluid pressures, and thus slope instability... meaning there was significant landslide activity. This landslide activity resulted in large amounts of sediment entering the water system, and causing the water treatment plant of Panama City to be closed down for almost a month. The impacts of this lack of clean drinking water can vary from increases in disease, illness and maybe even death. This interaction of several factors resulted in a number of negative impacts to Panama City.

A number of measures could be taken to prevent this sequence of events. Avoiding deforestation, in order to prevent erosion would be one measure to reduce the probability of landslides. Ensuring adequate drainage in slopes would also reduce the risk. This sequence of events should also inform and educate emergency planners - helping them understand the vulnerability of their water supply system. Back-up systems should be in place, bottled water stockpiled, and potentially boreholes drilled in key locations such as hospitals and schools.

Thursday, 3 March 2011

Case Study: Bududa Landslide, Uganda - March 2010


The United Nations Office for the Coordination of Humanitarian Affairs (UNOCHA), have stated (October 2010) that one of their key concerns in Eastern Uganda is flooding and landslides as a result of environmental degradation.

Eastern Uganda is generally a flat plateau, with the border between Kenya and Uganda dominated by the beautiful hills and slopes associated with Mount Elgon, an extinct shield volcano. These slopes are home to a number of communities. The higher elevation provides a more moderate climate than the plateau below, and the fertile soils are used by communities to grow crops, especially coffee. The slopes are also home to a wide variety of plants and forest – although a deforestation programme has been taking place in recent years.

Foothills of Mount Elgon

The slopes of Mount Elgon have been prone to a number of landslide events, as can be seen on aerial photographs. One of the biggest was this time last year (March 1st 2010) in Bududa. This landslide was preceded by significant rains. The slopes of Mount Elgon are the catchment area for a number of streams and rivers. The heavy rain caused a significant swell of these, and groundwater levels to rise. As groundwater levels rose, the instability of the slope increased due to the decrease in effective stress. This was likely exacerbated by the deforestation, with the soil losing anchorage and surface erosion more likely.

The total impact and effects of this landslide are unknown. Estimates of those who died are currently about 388, and significant numbers were left displaced as soil, mud and boulders submerged three villages. A number of school pupils took shelter in a health centre, which was tragically then destroyed.

From: http://www.afronline.org/?p=3835

As Uganda is entering a new rainy season one year on – there is a possibility that old landslides will be reactivated and new landslides occur. So what can be done to help reduce the tragic loss of life and economic costs of these disasters? In many ways it is hard to answer this question without fully understanding the landslide mechanisms and causes.

The Government of Uganda has criticised the communities for living in these high-vulnerability places, and advised that people move off the landslide prone slopes. This is, however, around half a million people – most of whom are subsistence or crop farmers. Relocating this amount of people, and finding the land for them to make a living, is no easy task. A review of vulnerability in the area could give more specific advice on which communities to relocate – but if crop yields (coffee etc) are less productive than their original plots, it may be difficult to persuade people not to return.

Research published this year in the African Journal of Agricultural Research suggests that farmers have a reasonably good knowledge of where landslides might hit, and some things they avoid (such as terracing) that can trigger landslides. The research suggests that possible interventions could be done using participatory methods. This would aim to help farmers better recognise causes and effects of landslides, and reduce activities that lead to instability - such as undercutting slopes for house construction. The research did not, however, discuss the effects of deforestation with the farmers. It is also unlikely that the threat could be removed simply by getting the farmers to change some practices. A bigger scale intervention, reseeding degraded land, planning and organising the slope-sided farming and improving drainage on the slopes would also be required.

Foothills of Mount Elgon: Concave Slopes identified by farmers as areas more vulnerable to landslides

It is likely that the best way to help reduce the effects of landslides in this area is a combination of a number of things:
  • Relocation in some areas of very high risk
  • Working with farmers to ensure their farming is more sustainable and avoids environmental degradation. Offering alternative housing styles to prevent the need for undercutting slopes.
  • Some possible engineering solutions - improving drainage and increasing toe weights to prevent instability.
It is hoped that the Ugandan Government and their development partners will act strongly to reduce the possibility of future disaster in this area.