Updates on the Cairo and Shanxi landslides

The search for victims in both the Manshiyet Nasser rockslide and Shanxi flowslide continues. The following is the latest news:

Manshiyet Nasser, Cairo
The number of recovered victims is now 107, with many more still believed to be trapped under the rubble. Clearly there are still extraordinary difficulties in getting beneath the large blocks. Interestingly, there is now a Quickbird image of the site, as highlighted by Almasry Alyoum. Below I have compared the before Google Earth image with the after Quickbird (click on the image for a better view - before in the left (Google Earth), after on the right (Quickbird)).

The Almasry article makes two interesting observations:

1. Since the Quickbird imagery was collected on 18th September, no official body has requested or made use of the images;
2. "The shots reveal that Muqattam Mountain may be vulnerable to other collapses, especially in its southern areas and in particular, its “Sharei tesa’ah” and “Maidan al-Naforah" areas, said geologist of the National Authority for Space Sciences Muhammad Naguib Hegazy"

There is also a nice article about the human aspect of vulnerability in shanty town here.

Shanxi flowslide

AP image of the landslide debris

There is a good article reviewing the causes of the Shanxi flowslide here. Interestingly it states that:

1. The number of fatalities is now 265;
2. The landslide was not associated with a spell of we weather. Indeed, "The whole county had received only a minimum rainfall amounting to 1.5 mm since the beginning of September, according to the Xiangfen bureau. This amount was not enough to sufficiently wet the ground, let alone cause a mudslide, said specialists at the China Meteorological Bureau."

Cairo landslide - the fall out continues

The Manshiet Nasser landslide continues to cause a huge political row in Cairo. Perhaps most importantly the population of the affected area remain deeply concerned about the nature of the response by the authorities, and their subsequent treatment. I suspect that this will rumble on for a long time. The rescue and recovery efforts have now ceased - to be honest this is probably the right decision as trying to excavate those boulders would be a terribly dangerous task, although one must feel deep sympathy for those whose relatives remain buried. Unfortunately, there is also a big political argument over the number of entombed victims - Almasry Alyoum reports that:

"Official papers said 92 corpses had been pulled out of the rubbles and only 12 corpses remained under the rocks. The Secretary General of the ruling National Democratic Party (NDP) Sheikhdom in Manshyat Nasser,however, said there are still 180 corpses under the rocks. This was confirmed by some Deweiqa inhabitants"

To me the higher figure would seem more likely, but who knows? I guess if the victims cannot be recovered then there is a need to try to ascertain a correct figure.

Meanwhile, The BBC is reporting that: "Prime Minister Ahmed Nazif will oversee a review of some 13 unauthorised suburbs of the city, with special focus on areas close to unstable land."

This seems reasonable, but such an approach will need to be undertaken with great care. Whilst people are undoubtedly at risk in some of these locations, making people homeless or putting them in refugee camps also carries very high risks. The key is to ascertain the actual nature of the hazard associated with the rockfalls. Whoever gets this task might like to look at some work that we undertook in Gibraltar to determine the hazards associated with rockfalls in residential areas:

Massey, C., Hodgson, I. and Petley, D.N. 2006. A rockfall simulation study for housing development in Gibraltar. Proceedings of the 10th IAEG Congress. Paper number 377. 9 pp.
Download the paper from here.

Loss of life in the China and Egypt landslidesp

Just a brief update on the latest estimate of the loss of life in the landslides last week in Egypt and China:


Taoshi (Shanxi): as of 16th September the official death toll is 259 people. Searches continue (see above AFP image).


Manshiet Nasser (Cairo): as of 16th September the official death toll is 92 people. It appears that recovery actions have now ceased as the site is considered to be too dangerous. There are likely to be many victims still buried. It is difficult to see how recovery operations can be safely undertaken under blocks such as the above (Reuters image).

Loss of life in the Manshiet Nasser (Cairo) and Taoshi township (Shaanxi) landslides

Xinhua is now reporting that the death toll in the Shaanxi landslide has now reached 254. They also report that the recovery teams are yet to search two channels in which local people believe more bodies are buried

AFP is reporting that the number of fatalities in the Manshiet Nasser (Cairo) landslide is now 82 people, with at least another week of recovery work to follow. Interestingly. they also report that "Residents have blamed the rock slide on work that had been going on for several weeks on the Moqattam hill overlooking the shantytown". It would be interesting to find out more about this work.

The location of the Cairo landslide

Thanks to posters over at the EgyptSearch forum, and in particular poster AntonD who finally identified the place, I can finally identify what I think is the location of the Cairo landslide. The point is at: 30 degrees 2.728 minutes N, 31 degrees 17.261 minutes E. This is the Google Earth image of this point:


The cliff from which the failure occurred is clear, as are the houses below. According to various people there has been considerable development in this area since the image was collected.

Helpfully, the following image is online of the cliff before the failure. The image is on a Panoramio site belonging to Hazem Mamdouh:
It appears to me that this image was taken from on top of the railway embankment. Compare that with this image, taken from Ghafari's Picassa site, of the aftermath:

I will try to post an analysis of the two images by Sunday.

In the meantime, there is a good analysis of the background to the landslide here. The official death toll is now 62, whilst the recovery operation looks increasingly difficult due to the size of the boulders.

The death toll in the Shaanxi tailings dam disaster is now listed as 151 people, with more victims to be recovered.

Updates on the Cairo and Shaanxi landslides

It is unusual to have two major stories running simultaneously about landslides so here is a combined update:

1. The Manshiet Nasser landslide in Cairo

The death toll in the Cairo landslide disaster continues to rise - it is now officially 69 people. There seems to be considerable confusion about how many people are left trapped - but is fair to say that there is now no hope of rescuing anyone alive. The magnitude of the task in terms of recovery is shown well by the picture above.

There is some discussion on the newswires about the causes, with several suggestions that sewage in the joints may have played a role. To me this is far from clear. There are also now suggestions that quarrying may have occurred on the rock face - this would be the first thing that I would look at if I was investigating the slide.

Meanwhile, there appears to be considerable political fall-out over both the government's failure to recognise the threat posed by this slope (see here) and the slowness of the response. This has led the government to seal off the site. One wonders whether we will ever know the true toll of this event.

2. The Taoshi township flowslide in Shaaxi



The pictures emerging from the Taoshi township site continue to horrify. The official death toll is now 128, but there can be no hope of anyone else being found alive. Officials are now admitting that the number of missing people is "several hundred". The debris flow was reportedly three stories high and 600 m wide when it hit an office building, a market and several houses. At the time the market was just starting and there was a meeting, attended by over 100 people, in the offices of the mine company. Only three people survived the meeting.

Again, the difficulties of recovering victims here may make it difficult to estimate the true impact of this event.

Catastrophic rockfalls in the Middle East

The terrible landslide at El Doweiqa in the Manshiet Nasser slum in Cairo (see earlier posts here and here) continues to shock. The death toll has now reached 45 people, with many more still buried in the debris. News reports suggest that there is growing dissatisfaction with the response of the authorities in Egypt. To be fair, relatives in disasters such as this are often very frustrated at the speed of the response - for understandable reasons. Excavating blocks as large as this whilst keeping the rescuers safe is a terribly difficult task.

However, of interest is the similarities between this disaster and one that occurred in Yemen on 28th December 2005. This landslide occurred at the village of al-Dhafir, about 50 km from the capital Sanaa. As with Manshiet Nasser, the landslide occurred as a result of the collapse of massive bedrock blocks from an escarpment. Again, as in Cairo, houses were utterly flattened by the landslide. This disaster killed 65 people. The images below of the disaster are from AFP via the BBC. The similarities to the Cairo event are clear:


I have very rarely seen landslides like this from other parts of the world. What is unusual is the size of the blocks (huge) and the mechanism of failure (toppling). This combination is not seen very frequently. So why does the Middle East suffer this type of unusual failure?

I suspect that the answer lies in an unusual juxtaposition of geology and climate. The geology provides a strong rock with a simple joint set in which the spaces between the joints are large. This allows rare detachments of very large blocks. If the rock was weaker or more closely jointed then the blocks that fall off would be smaller - i.e. there would be more falls, each of a lower volume. The climate element comes from the aridity, which means that failure is not triggered by the pore pressure effects seen elsewhere. An additional factor is probably that the dry climate means that the rate of weathering is low. So a wetter climate would probably trigger more failures, each of a smaller volume.

The reports in Cairo suggest that the local people feel that water (or sewage) leaking into the rock has been a factor. This may be the case, although the mechanism of failure is not obvious. I would be interested to know if the slope has been quarried either officially or unofficially. For example, have pieces been hacked out to be used for building stone? Or have pieces been detached to create space for more buildings? This is so often the cause of rock slope collapses in inhabited areas.

The Cairo rockslide foreseen?

EPA/MIKE NELSON image showing the displaced blocks at El Doweiqa

The death toll in the rock slide at El Doweiqa in the Manshiet Nasser slum of east Cairo is slowly creeping upwards. At the time of writing it has exceeded 30 people, but unfortunately as the image below shows the likelihood is that it will be much higher once these huge blocks have been shifted (if ever). As an aside, the news reports tend to refer to these blocks as weighing hundreds of tonnes. In fact they are probably much heavier than this - a 10 x 10 x 10 m block typically weighs over 2300 tonnes. Some of these blocks may be substantially larger than this, suggesting that blasting will be the only option if the victims' remains are to be recovered.

EPA/MIKE NELSON image showing the displaced blocks at El Doweiqa

There are interesting sets of amateur images here and here.

Most interesting however is an article from the "Egyptian Gazette" dated 23rd July 2006. I have reproduced the article below. Compare the photograph with the image at the top of this posting - it is clearly the same location.

The text of this article says the following:

"NOTHING can be more difficult for a human being than to wait for the death that's drawing nigh. How can someone live in a house at the bottom of a hill while a huge rock is poised precariously at the top, ready to roll down and smash that house to smithereens? Gomaa Abdel-Bari, whose family live along with 2,800 others in el-Doweiqa, have experienced rocks falling on them from the hills above, damaging the walls of their homes.

"I've made numerous complaints to official bodies, including the local administration and human rights organisations, but in vain," Abdel-Bari told October weekly magazine. To prevent more rock falls, local inhabitants say they want to demolish the rocks that threaten them, with the help of machinery belonging to the local council. "We've already broken up some of the rocks, at a cost of LE4,000, money collected from poor residents," explains Ashraf Abdel-Tawwab.

But we cannot afford to demolish the rest on our own. Besides, it's dangerous work. If one rock comes loose, it can cause a domino effect, resulting in a disastrous avalanche," he says bitterly. Ahmed Hosni, a worker, explains that sewage leaks through the rocks, dislodging them and causing them to come tumbling down on their homes.

Meanwhile, a man called Farid Abdel-Tawwab complains of the snakes and dangerous insects that have killed many people in this randomly built area. He too says that the rock falls are to be blamed on sewage leaks. El-Doweiqa forms part of Manshiyet Nasser, the biggest shanty town in Cairo and a big headache for successive governments. It occupies around 850 feddans of land and is home to 1.3 million people, who live in appalling conditions, deprived of clean water, adequate sewerage and even fresh air, due to the huge piles of garbage collected and sorted there by the garbage collectors from all over the capital.

At the end of the last century the Government started to replan Manshiyet Nasser, including el-Doweiqa and other districts. The dea was to replace the old, unplanned districts with new, modern ones. Germany and Abu Dhabi supported the ambitious project. However, no-one knows exactly when the development project will reach the Khazan area of el-Doweiqa and whether it will be in time to prevent another tragedy like that in el-Moqattam in 1992, when a huge rock crushed dozens of citizens to death."

Thus, this two year old article appears to foresee the event that occurred this weekend. One wonders if the interviewees, and their families, survived. Tragic.

Early reports of a rockslide disaster in Egypt

The newswires are providing early reports of a terrible rockslide at Deweka (also reported as Bekheit and Manshiyet Nasron) on the outskirts of Cairo in Egypt. The slide appears to be a rather strange failure of a rock slope, releasing huge boulders that have buried several (and possibly many) buildings.

This Al Jazeera post contains a very useful report and also has this image of the site:


They are reporting that "Officials said at least eight rocks, some measuring 30m high, had buried more than 50 homes in the poor district of Manshiyet Nasron on Saturday. At least 18 people have been declared dead and 35 injured. Some estimates put the number of buried at 500."

Early reports like this often over-estimate the losses in an event such as this, but if these boulders have hit residential buildings then the toll could be terrible. Al Jazeera also note that "In a survey carried out by UN Habitat, a human settlement programme, Manshiyet Nasron is described as "the largest squatter/informal area in Cairo. There are 350,000 persons living in this area on about 850 acres with a gross residential density more than 400 persons/acre".

"The area is suffering from poor living qualities, inadequate services, lack of infrastructure, and deteriorated environmental conditions. The site is characterised by sharp contour variations ranging between 56 and 200m," the survey said."

The final point to note is that Al Jazeera claim that "Manshiyet Nasron residents had informed the authorities a year ago that there was a split between the rocks, a potential danger to the homes below." This would make sense as the image above seems to show dry conditions and there are no reports of an earthquake. Thus, the landslide is most likely to have been caused either by progressive failure (i.e. a slow loss of strength through time) or slope cutting.

I will post again when I have more.