Multiple Generations of Dark Slope Streaks on a Crater in Arabia Terra
Multiple Generations of Dark Slope Streaks on a Crater in Arabia Terra
PSP_008322_1865  Science Theme: Glacial/Periglacial Processes
This image is of a crater in Arabia Terra, which is a large swath of bright (high albedo) terrain in the Martian cratered uplands. The steep interior walls of the crater are covered with numerous slope streaks, thought to be caused by dust avalanches that strip away layers of dust to reveal a darker underlying surface.

Here, multiple generations of slope streaks are present. The most recent features appear the darkest, and they appear to gradually brighten over time as more dust is deposited from the thin Martian atmosphere. Causes of dust avalanches include small impact craters, rockfalls, and oversteepening of the surface as dust accumulates. This last mechanism is similar to the way in which snow-covered slopes in high mountain areas on Earth accumulate enough snow to become gravitationally unstable, leading eventually to avalanches.

Written by: Brad Thomson  (9 July 2008)
Acquisition date
05 May 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
272.7 km (169.5 miles)

Original image scale range
from 27.3 cm/pixel (with 1 x 1 binning) to 54.6 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

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Emission angle

Phase angle

Solar incidence angle
49°, with the Sun about 41° above the horizon

Solar longitude
68.0°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  30.9°
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Black & white is 5 km across; enhanced color about 1 km
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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.