These images explore the southwest wall of Pursat, an 18-kilometer-diameter crater in Mars' southern highlands. The leftmost image was taken by Mars Reconnaissance Orbiter CTX in February 2008 (P16_007185_1425_XN_37S228W). The center image shows the same location as seen one Earth year later (B06_011958_1425_XN_37S229W). During the time separating the two images, a new light-toned flow appeared in the crater wall. The rightmost panel contains a view of the new flow feature as seen by HiRISE in March, 2009 (ESP_012380_1425). The flow exhibits a number of features characteristic of debris flows: evidence for the flow traveling around obstacles, for ponding of the flow in topographic depressions, for the flow overtopping those depressions and spilling over, for raised deposits on channel banks, for braiding of the flow bed where it meets the lower slope of the crater floor, long runout onto the crater floor, and lobate ends of the flow deposit.

NASA / JPL / MSSS / UA / annotated by Tanya Harrison