Sometimes a central pit forms inside some Martian craters, especially when there’s substantial ground ice. Such is the case in this observation.
Sometimes what we call “mass wasting” processes (think small avalanches or landslides) occur on the slopes of the central pit. We took this image to search for any recent activity that would add to or modify previously identified gullies .
Written by: Kirby Runyon (14 October 2015)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_042615_1385
Image: NASA/JPL/University of Arizona