3 April 2013

More information about the Brazil riverbank failure landslide

Posted by Dave Petley

The Brazil riverbank landslide, which killed six people last week, is an intriguing event.  In the comments from my post yesterday, Raphael Rocha kindly provided detailed information about the landslide (including a correction to the location).  This certainly justifies a separate post

One of the links that he provided was to this site, which has an image of the area of land that collapsed:


And an aerial image of the site after the accident:


A translation of the text on that site is as follows:

The main hypothesis about the cause of the accident in the Port city of Santana, Amapá, last Thursday (28), has been proposed. A technical report, released on Monday pointed out that the lack of proper structure at the base of the pier owned by the Anglo American company triggered a landslide in the area that was part of the floating port on the banks of the Amazon River. The accident killed six people working on the site.

The official explanation has been proposed by the technical staff of the Institute of the Environment and Spatial Planning of the State of Amapá (Imap). The cause of the accident was the intense movement of trucks and cranes loaded with tons of iron ore at the company pier. At the time of the accident, there were half a million tonnes of iron ore at the pier. “We note that this is an impact point. The observations lead to several signs of fragility in the soil that could not stand the pressure of intense movement associated with the company activities, “explained the director of Imap, Mauricio Souza.

There is a reasonably recent image of the loading point on this website:


So, this appears to be a large-scale failure of the riverbank associated with loading caused by the weight of iron ore that was being stored.  This collapse generated a localised wave that destroyed the pier, killing the three victims.  Interestingly, the wave was caught on video on a nearby small port.  This can be seen below.  The video is long; the action occurs at about 15 minutes from the start of the film.