1 October 2008
Although landslides on other planets have not been a major theme of this blog, there is an interesting area of science that focuses on these intriguing phenomena. Of course a great deal of this research is quite difficult given our poor knowledge of the conditions on and in the slopes when they occur. The availability of increasingly high resolution imagery is however helping in the understanding of these features. There is a hope that we might understand terrestrial landslides better if we can see how slides operate in other environments, although to date I must admit that I am unconvinced that this has really happened.
Yesterday NASA released the image below, which shows an area of Mars with a quite interesting landslide. It was collected by Mars Odyssey THEMIS (acknowledgement to NASA/JPL/Arizona State University):
At first the landslide might not be obvious, but look closely on the centre right side – it is clear that the slide is a ridge failure with a reasonably long run-out. I have zoomed into the image to show the landslide below (Fig. 2):
I have processed and annotated the image (Fig. 3) to highlight some key features. I think (though this is unconfirmed) that the landslide is about 2 km wide and 6 km long. Note that the presumably more resistant material that forms the ridge appears to be intact on the landslide body. The landslide has two smaller failures on its flank. Finally, it also appears to have a few small craters on it, which presumably means that it is not too recent (UPDATE: thanks to Dr Mauri McSaveney for pointing out that not too recent in this case probably means 2-3 billion years old).
Similar landslides do occur on Earth. For example, Fig. 4 shows the Frank landslide, which I have described before. Note that in the Mars case the slipped block has only partially broken up, whilst at Frank it disintegrated completely to form a rapid flow. I am sure that there are better examples from Earth, but I cannot think of them at the moment. Can anyone come up with one?