8 May 2019

Hargraves Crater: is this a landslide on Mars? Your views please

Posted by Dave Petley

Hargraves Crater: is this a landslide on Mars? Your views please

Yesterday the NASA HiRISE team posted an image that they described as a “Distinctive Lobe of Northern Hargraves Crater Ejecta Blanket“. This is the salient part of the image:-

Hargraves Crater.

Distinctive Lobe of Northern Hargraves Crater Ejecta Blanket“. Image via NASA/JPL/University of Arizona.


On Twitter, Andrew Wiebusch raised the possibility that this is not an ejecta blanket, but is instead a sign of slope instability:-

Hargraves Crater

Tweets from Andrew Wiebusch regarding the possibility that a feature at Hargraves Crater on Mars is a sign of slope instability


I am no expert on landslide features on Mars (or on other planetary bodies), but I can understand the interpretation that Andrew is making.  There appears to be a large arcuate scar, and ridges occur within this that look like tension features and scarps.  The main body of the feature appears to be disrupted compared with the surrounding topography, much as landslides on Earth develop distinctive disrupted hummocky terrain.  The main landslide body appears to lie within, and flow from, a bowl-shaped feature .

My strong sense is that such a feature on Earth would be interpreted as a sign of past slope instability, assuming that the regional slope coincided with the observed landslide topography (I have no sense of the regional slope in this case).  However, I am more hesitant about making such an interpretation for a feature on Mars. So your views are welcome via the comments.  Do you agree that this might be a landslide?  If so, why do you make this interpretation?  If not, what are the features that differentiate this from a slope instability?

The comments are moderated (to try to avoid the deluge of spam that the blog attracts), so please be patient as it might take a few hours for your post to appear.  Unfortunately my day job gets in the way of the important things in life ;-).