You are currently browsing the category archive for the ‘Landslides’ category.
A little over a month ago I gave a talk at the Vajont 2013 conference on the topic of landslides and large dams. At the time I committed to making the Powerpoint file available online, so here it is:
The file is located on slideshare – you should be able to download the powerpoint file from there. The piece is also written up in an article for the conference paper – reference below. The paper can be accessed, for free, from the conference website. The other talks and papers can also be accessed from the conference website.
In this work I looked at the Durham Fatal Landslide Database to try to understand fatality-inducing landslides associated with large dams over the last decade. My analysis of the dataset suggested that in total there were exactly 500 deaths in 37 landslide events in the ten years between 2003 and 2012. Surprisingly, with one exception these were not landslides associated with the collapse of reservoir flanks (although interesting there was an event of this type in China earlier this year). Most of the landslides were either failures at the construction sites of large dams or at the sites of workers camps. Read the rest of this entry »
When I was studying Physics at school, we were shown the famous regelation experiment in which a wire is placed over a block of ice and a weight is attached to each end. Though time the pressure on the wire causes melting of the ice, and the wire slowly cuts its way through the block, and eventually the weights and wire fall to the ground. As the wire passes through, the water refreezes, such that the wire appears to pass magically through the ice.
There are various versions of this experiment on YouTube, of which this is about the best:
The interesting part of this experiment starts at about 1:22 and ends at 1:40 (in the speeded up sequence). Of course when the wire finally cuts through the ice the weights collapse to the floor with a great crash – the very last moments before this are shown below: Read the rest of this entry »
Regular readers will know that the lack of attention that is paid to potential and actual landslide impacts during earthquakes in upland areas is a real hobby-horse of mine. Time and again we see the situation in which there is a lack of preparedness for landslides, causing huge disruption to the response and recovery operations, even though the threat was entirely forseeable. It is pleasing to see increased interest in the science of this issue in recent years, with a succession of good papers exploring both the mechanics of the landslide process (which is a very complex problem) and the likely occurrence of landslides.
This week, a paper has been electronically released on the BSSA website, to appear in a forthcoming edition of the journal, which examines the likely impact of landslides in the event of a Mw=7.0 earthquake of a “Seattle earthquake” – i.e. a quake on the Seattle Fault in Seattle, Washington. The paper, Allstadt et al. (2013) uses synthetic broadband seismograms to model shallow landslides in the area likely toi be affected by such an earthquake. Such an analysis is complex and computationally extremely intensive. I should also note that the technique uses the so-called Newmark method to model the slope behaviour. Newmark is basically the best technique that we have at our disposal at present, and so the team were right to do this, but in my view it is somewhat deficient in terms of the ways in which it models slope behaviour. We need a better technique; the trouble is that at the moment we do not have one. Read the rest of this entry »
Wednesday of next week will mark the 50th anniversary of the Vajont disaster, which occurred on 9th October 1963. This was of course the worst landslide disaster in European history. In addition it marked a watershed in a number of areas, not least landslide management and the development of large dams. On Thursday Michele and I will set off from the UK to attend the conference to mark the anniversary – the organisers were kind enough to invite me to give one of the keynote addresses, which will be on the topic of fatal landslides and large dams over the last decade. I will make it available online in due course.
In the meantime, I thought it would be useful to provide a list of some of the key resources that are available on the dam and the landslide disaster: Read the rest of this entry »
Over the last few days Central China has been experiencing exceptionally heavy monsoon rainfall, causing very high levels of damage. The TRMM data for landslide potential for the last seven days of rainfall highlights the areas considered likely to be affected by landslides (and note that there are also substantial parts of N. India and Nepal that are experiencing problems:
Unfortunately, the worst of the rainfall appears to have affected the areas struck by the 2008 Wenchuan earthquake in Sichuan Province. This is a zone that remains very vulnerable to landslides because of the legacy of the seismic even, compounded by inappropriate development in the rush to rebuild after the earthquake. The effects have been disastrous. The largest impact to date is the landslide at Sanxi in the area administered by Dujiangyan City, which is reported to have killed 12 people whilst a further 11 are missing, with very limited chances of survival. The landslide is reportedly very large, with a travel distance of 2 km and a volume of 1.5 million cubic metres. Read the rest of this entry »