Slope Streak South of Olympus Mons
Slope Streak South of Olympus Mons
PSP_003239_1870  Science Theme: Mass Wasting Processes
This observation reveals slope streaks in an area south of Olympus Mons in the Northern hemisphere of Mars.

These features are found along the slopes of impact craters, buttes, knobs, ridges, and troughs on Mars. Streaks generally start at a point source and widen downslope, traveling over and sometimes around various obstacles.

The subimage shows a very wide dark slope that has developed small fingers at its termius. The dark slope streak does not appear to have relief and does not disturb the pre-existing surface leaving the underlying topography intact beneath its dark trail. This can be seen particularly well near the streak termination. There are also no observable deposits of displaced materials along the terminus.

Surrounding the dark slope streak are multiple 1 meter deep, triangular faceted scars left behind from avalanched slope materials. The high standing remnant surfaces on either side of the lower scarred surface are clearly visible. Avalanche scars are sometimes found in areas where slope streaks have formed but they are believed to be unrelated. The trail of the dark slope streak appears to cross over the avalanche scars suggesting that the slope streak formed more recently.

Slope streak formation is among the few known processes currently active on Mars. While their mechanism of formation and triggering is debated, they are most commonly believed to form by downslope movement of extremely dry sand or very fine-grained dust in an almost fluidlike manner (analogous to a terrestrial snow avalanche) exposing darker underlying material.

Other ideas include the triggering of slope streak formation by possible concentrations of near-surface ice or scouring of the surface by running water from aquifers intercepting slope faces, briny liquid flows, dry granular flow, mixed water-dust flows, and/or hydrothermal activity.

Written by: Maria Banks  (16 May 2007)
Acquisition date
05 April 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
273.7 km (170.1 miles)

Original image scale range
54.9 cm/pixel (with 2 x 2 binning) so objects ~165 cm across are resolved

Map projected scale
50 cm/pixel and North is up

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Emission angle

Phase angle

Solar incidence angle
57°, with the Sun about 33° above the horizon

Solar longitude
213.6°, Northern Autumn

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North azimuth:  97°
Sub-solar azimuth:  345.0°
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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.