9 October 2019
Whanganui: a large landslide on State Highway 4 in New Zealand
Late last week a large landslide developed on State Highway 4 between Whanganui and Raetihi in Ruapehu district of New Zealand. The landslide, which reportedly has been developing for some time, has destroyed the road, causing considerable local disruption. A local photographer, Mark Brimblecombe, collected a series of images of the landslide via a drone at the weekend. These stunning images capture the size and scale of the failure beautifully.
This image is a good view of the scale of the landslide and the level of damage that it has caused:-
Meanwhile this image shows a different view of the extent of the landslide:-
Note the total destruction of the section of road and also the extent of the tension cracks up the slope (see below), especially on the left hand side. Also worth noting is the landscape in the distance on the far left side – this shows the distinctive features of a potential ancient, now inactive landslide.
I noted above the full extent of the tension cracks extending up the slope. This image, also captured by Mark, shows this in more detail:-
These image suggest that there is a significant volume of material still to be released in this landslide. Reconstructing the road is going to be a very substantial challenge given the magnitude of the landslide, and the volume of partially failure material. To give an idea of the scale of the disruption, RNZ reports that:
“For local logging truck company, McCarthy Transport, the detour was adding an extra 130 to 200 kilometres to their trip, the company’s chief executive Steve McDougall said.”
Many thanks to those people who highlighted this to me. My blog really depends on the community effort in which people highlight such events, so your help is really appreciated. Thanks also to Mark Brimblecombe for both collecting the images and for sharing them so openly. They are magnificent.