16 March 2015

Yeager Airport landslide – new videos on Youtube portray the damage

Posted by Dave Petley

Yeager Airport landslide

The latest news on the Yeager Airport landslide is that movement has new ceased, although the total displacements that have accumulated are now substantially larger than they were when I posted on Friday.  The landslide has now destroyed the church at the foot of the slope for example, as this Charleston Daily Mail image shows:

Yeager Airport landslide

Charleston Daily Mail

.

This Youtube video captures rather nicely a fairly early stage in the movement event.  Note that a quite large displacement had developed in the rear of the landslide.  The internal deformation in the landslide mass appears to have been inducing smaller, flow-type failures in the frontal portion of the landslide:

.

.

This is a really good drone film of the landslide mass, showing the destroyed church and the flooding induced by the blockage in the river channel:

.

.

This still image from the video shows the displaced mass of the landslide, which has now undergone a very substantial amount of internal deformation:

Yeager Airport landslide.

The basal surface of the landslide remains unclear, but the lack of bedrock in the image suggests that my earlier hypothesis that the Yeager Airport landslide might have been induced by failure in the underlying substrate might not be correct.  The rear scarp is now very steep in weak materials, suggesting that quite urgent work is needed to protect the remainder of the overrun area of the runway.  The risk of more substantial flooding has been reduced by the completion of the channel around the tow of the landslide, meaning that the risk to the remaining houses on Keystone Drive has now reduced.  Unfortunately though the residents will suffer considerable disruption for many months as the mitigation of this landslide is going to be a very major task.