7 January 2009

An update on landslides in Beichuan

Posted by Dave Petley

At the time of the Wenchuan earthquake I posted on numerous occasions about the landslides around the town of Beichuan. One of the concerns has always been the likely behaviour of the landslides during heavy rainfall events.

As part of the forthcoming Sinorock 2009 conference in Hong Kong there will be a tour to the earthquake-affected area to look at and discuss the landslides. The organisers have put together a web page about this tour (see here). Interestingly, thy have posted three images of Beichuan:

First, before the earthquake:

Second after the earthquake:

And third, most importantly, after a very intense rainfall event on 24th September 2008:

Note the extensive movement of sediment, which has caused the river bed to agrade and bury many structures. This is very similar to what happened in parts of Taiwan after the 1999 Chi-Chi earthquake. Such behaviour represents a serious challenge for the authorities.