Guatemala landslide - new satellite image

The Advanced Land Imager instrument of the NASA Earth Observation satellite EO-1 has recently collected an image of the Guatemalan landslide, which they have made available online. The image is here. I have cropped it to show just the slide - it is quite useful:

Landslide hazard and the Guatemala rockslide

As commenters on my earlier threads have pointed out (thanks to them), the location of the landslide in Guatemala can now be pinpointed using a map produced by CONRED. This map comes from a very useful report, with some good images of the rescue and recovery operation, available here. I have reproduced the map below (click on the map for a better view):

Helpfully, this allows the location to be pinpointed on Google Earth (unfortunately the high resolution imagery starts just east of the landslide location - click on the image for a decent view):


Satellite imagery can be difficult to interpret until a 3D perspective is available. This is one of the key strengths of Google Earth. The situation becomes so much clearer when a perspective view is taken:

A magnified and annotated image below shows that the landslide occurred in a very clear bowl shaped feature that would cause any good geomorphologist to be very nervous in terms of slope stability. I have highlighted the boundary of the bowl and the location of the landslide:


Note that there are a number of other locations that look vulnerable to slope instability as well, such as the bowl to the east of the area that failed. Reports suggest that the authorities are being cautious and have arranged evacuations. This is probably prudent, but it is important that a proper hazard assessment is undertaken, and that the risks associated with landslides are then balanced against the (social) risks to the people associated with moving them from their homes and their land.

The Guatemala landslide - video of the failure in December

The Guatemalan landslide becomes more interesting by the day. It is now apparent that the first failure, which occurred on 14th December and killed five people (the remains of three of whom were not recovered) was also caught on video. This is available on Youtube. I have embedded it below, so should work:


If not, then it can be viewed here.

Guatemala landslide

As the Guatemala landslide now fades from media prominence, Reuters have released probably the best image to date of the landslide site:

It is now clear that this was a a large rockslide (not a mudslide as reported elsewhere).

AP have released a good image of the site:


Whilst this Reuters image shows the runout of the landslide quite well:



Finally, CONRED released this image of the site to show the ongoing rockfall activity that caused suspension of rescue operations:

Meanwhile the number of recovered victims has now reached 37. About 50 victims remain buried in the debris.

Finally, there are various reports that an evaluation of the site has determined that the area around the landslide is too dangerous for habitation. My suspcicion is that this is right - the landslide appears to me to have occurred in a much larger landslide scar. I will post again on this soon.

Another video of the Guatemala landslide

It now appears that there are two videos of the Guatemala landslide. The second one, which is not as clear as the original, has appeared on the Telediaro 3 web site. It can be viewed here:

http://www.telediario.com.gt/index.php?id=15366&tim=#

Meanwhile, there remains considerable uncertainty as to the number of victims (we may never know for certain I suspect), whilst speculation is intensifying regarding the cause. Given the clear size of the landslide (see the video plus the image below from Prensa Libre), comments elsewhere that road widening was the primary trigger look to be wide of the improbable. Clearly there is no record of seismicity or of intense rainfall (everything looks dry in the video). The most likely trigger is therefore progressive failure, which is consistent with reports of increased activity in the fortnight before the failure, reports of the slope emitting noises and the fact that the road had been closed prior to collapse.


Finally, there is continued concerns that a second major failure might occur given the oversteepened nature of the upper part of the slope.

The Guatemala landslide was caught on video!

Unbelievably, it turns out that the Guatemalan landslide, which it appears killed at least 42 people, was caught on video. Geologist Marlon Contreras was recording at the edge of the site when the failure occurred. The video captures the movement, although mercifully little of the detail. The video can be viewed at this web page:

http://www.prensalibre.com/pl/2009/enero/06/multimedia.html

The failure that happens 1 minute and 50 seconds into the video defies belief! I urge you to take a look at the video.


Meanwhile, and quite rightly, rescue operations have been halted due to the dangers of continued falling rocks to the rescuers. Given that there is no possibility of any survivors this has to be the right decision, harsh though it undoubtedly is.

Finally, there is still a huge variation in the reported number of victims. Prensa Libre is reporting that 42 people were affected, but other news agencies suggest that it might be double this total, or even more.

Guatemala landslide

The first major landslide event of 2008 occurred on Sunday in Alta Verapaz in northern Guatemala. At the moment reports are somewhat fragmented, but the Guatemalan newspaper Prensa Libre has published the following (not great quality) image. I have tried to enhance it as much as I can:

Clearly this is a major failure - the news report suggests a mass of10,000 tonnes. To date that there are 29 known fatalities plus 15 people reported injured. It appears that there are concerns that the death toll may be much higher as there were 140 people on the road at the time of the failure.

In fact the Prensa Libre report is impressive in terms of the level of geological detail that they provide - far better than is usually the case. A number of key issues emerge:

1. This same stretch of road suffered a landslide on 14th December that killed two people;
2. It was known that another failure was likely, such that the road had been closed. The 140 potential victims appear to have disobeyed instructions when they walked across the affected section;
3. The landslide has occurred in an area that is traversed by a known fault, which has weakened the ground and caused water seepage;
4. Further failures are feared.

For info the failure appears to have occurred somewhere on the section of road shown below, although the Google Earth image is not good enough to pinpoint its likely location properly (click on the image for a better view):


I will post more as details become available.