This observation features three newly-formed slope streaks. These are features which occur on crater walls, hills, and other slopes on Mars.

They always begin at a point source and widen downslope, sometimes weaving around existing topographic features (such as dunes or craters), but other times they flow over them. Many slope streaks do not show topographic relief in available images, and there are no observable deposits of displaced materials surrounding their borders.

In general, slope streaks tend to be many hundreds of meters long and less than 200 meters wide. They are observed in varying shades of darkness, where lighter-toned streaks appear to be older than darker ones. The formation mechanism responsible for slope streaks is still under debate; theories range from dry dust avalanches (most widely-accepted theory) to briney water seepage.

Slope streak formation is among the few surface processes known to be currently active on Mars, making slope streaks some of the youngest features on Mars. A comparison of this HiRISE image with MOC image E04-01817 shows that three new slope streaks have formed during the six years separating these images (2001 - 2007). The shortest time frame in which new slope streaks have been observed to form is six months (MOC images SP2-37303 and E02-02379), though it is not yet known how long it actually takes for a slope streak to form.

MOC image E04-01817 courtesy of NASA/JPL/Malin Space Science Systems.

Written by: Tahirih Motazedian

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible: Image: NASA/JPL/University of Arizona

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.