Watch for Falling Rocks!
Watch for Falling Rocks!
ESP_031280_1705  Science Theme: Mass Wasting Processes
The original rationale behind this observation was to examine the slopes for changes since an earlier image in the same location. However, a feature that has NOT changed much since then still remains quite eye-catching. Multiple boulder tracks spill down the side of the crater.

When boulders roll down a dusty Martian slope, they can leave long, dotted tracks behind on the slope surface. Boulder tracks, like slope streaks, can be either brighter or darker than the surrounding terrain. The many boulder tracks in this image all seem to emanate from a small alcove near the rim of the crater. They spread out downslope and finally terminate near the crater floor. A high-contrast stretch of the area where the tracks stop shows lots of boulders, some still at the ends of the tracks.

HiRISE has seen boulder tracks fade over time in other locations. However, as compared to ESP_017975_1705 (taken in May 2010), the tracks in this image (taken in March 2013) don't seem to have faded as dramatically as that earlier example, despite a larger lapse in time between images. This might be because the crater in this image is in a less-dusty area of Mars.

Note: the above image has been rotated 90 degree counterclockwise for display purposes.

Written by: Nicole Baugh  (1 May 2013)
Acquisition date
29 March 2013

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
262.5 km (163.2 miles)

Original image scale range
26.3 cm/pixel (with 1 x 1 binning) so objects ~79 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
38°, with the Sun about 52° above the horizon

Solar longitude
291.4°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  339.2°
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Black & white is 5 km across; enhanced color about 1 km
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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:

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. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.