Planetary Geomorphology Image of the Month, March 2015: Jessica Watkins (University of California, Los Angeles).
Long-runout (> 50 km) subaerial mass movements are rare on Earth but it is one of the most prominent geomorphic processes shaping Valles Marineris in equatorial Mars. It has occurred widely and nearly continuously within the canyon system over the past 3.5 billion years (Quantin et al., 2004).
There is a characteristic surface morphology exhibited by many Valles Marineris landslides despite their diverse ages. It consists of an (upslope) inner zone with rotated blocks, and a long-runout outer (or distal) zone, characterized by thin sheets spreading over 10s of km across the trough floor, marked by longitudinal grooves… [More at link]