15 June 2018
Kilauea volcano: large-scale slumping on the rim of Halema‘uma‘u crater
The ongoing major eruptive event at Kilauea volcano in Hawaii has generated a wide range of spectacular videos and extensive news coverage. At the summit of Kilauea is the large Halema‘uma‘u crater, which has been undergoing major morphological changes in response to recent events. Most importantly, a little more than a month ago the lava lake that had occupied this space drained down. In response, the walls of the crater have undergone large-scale slumping. Volcanic landslides are well-documented, but rarely in this level of detail.
The USGS has a page that provides their latest photographs and videos of the Kilauea eruptive event, which includes remarkable imagery of these slumps. For example, this image shows the sequential curved tension cracks that mark the back of a series of large slumped blocks:-
Whilst the image below gives a wider perspective view of this slumping process. In some cases the slumped blocks have deformed by over 100 metres:-
There is a wonderful drone video, collected this week, that provides a panoramic overview of the deformation.
This is a textbook case of slumping in response to changes in the local stress state. We see successive slump blocks like this in conventional landslides too, though rarely with such clarity. A very interesting element of this is the lack of rotation in the blocks, none of which appear to be backtilted. I wonder if this is because of the circular planform of the blocks (whereas in non-volcanic landslides they tend to have a more linear planform). Presumably this circular shape inhibits the development of rotation.
The USGS have been monitoring the development of these slumps at Kilauea, so in due course there should be some fantastic data on the ways in which these landslides evolve.