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.

Hunza debris flow video

You probably guessed that I am on holiday this week (normal service will be resumed at the weekend), but I thought I'd quickly post this new debris flow video from Hunza in Pakistan. The interesting but starts at about 1 minute 15 seconds:

Dust cloud video indicates substantial numbers of landslides from the Baja California earthquake in Mexico

The Mw=7.2 earthquake on the Laguna Salada fault in Mexico on Sunday was certainly sufficiently large and shallow (10 km) to generate landslides, and there are areas of mountains that provide enough relief for slides to develop.  To date the number of reports of slides is quite limited, but CNN has this amazing amateur footage of the mountains to the south of Mexicali.  The huge dust clouds were almost certainly generated by landslides (see below the fold):





It will certainly be interesting to see what these slides look like on the ground, but given the arid environment shallow rockslides may well be a key component.

Forced to flee

IRIN, the UN Office for the Coordination of Human Affairs, has produced a rather nice video about the impact of lahars (a landslide in comparatively young volcanic materials) in the Philippines. The landslide occurred during Typhoon Durian (known in the Philippines as typhoon Reming) in 2006.

Wikipedia image of the track of typhoon Durian (Reming) in 2006. The orange dots indicate the locations at which the typhoon was at its maximum intensity

NASA image, derived from TRMM data, of the rainfall associated with typhoon Durian (Reming). Note that although 200 mm is very high, far greater rainfall totals are often associated with large typhoons.

Lahars surged down the flanks of Mount Mayon, killing over a thousand people. The film focuses on a comparatively affluent family whose house and land was hit by the lahar. The children's mother was killed, their house destroyed and their land inundated. In the aftermath the government declared the flanks of the volcano to be too hazardous, meaning that the family were moved into a refugee camp. The father of the family is relentlessly cheerful (except when he revisits his house and sees his wife's pillow), but his desperation is clear to see.

The film is available here.

Google Earth image of Mount Mayon, showing a lahar deposit. Click on the image for a full size view in a new window.

In many ways the most interesting aspect is the way that the film balances the hazards associated with the natural processes (i.e. the danger of another event) with the hazards associated with displaced people moving to new settlements that can quickly become slums. It is an interesting film that brings home some fundamental issues in a very real way, without presenting anything terribly new. It is certainly useful for teaching both in schools and at undergraduate level, and as a reminder to those of us working on hazards as to the complexity of the impact of decisions.

UNOSAT image of the impact of Typhoon Reming on Mount Mayon, showing in particular the multiple lahar tracks. Note the degree to which the lahars have impacted upon the towns.