The Dark Side of Dust Avalanches
NASA/JPL-Caltech/UArizona
The Dark Side of Dust Avalanches
ESP_055285_2030  Science Theme: Mass Wasting Processes
Changes on the Martian surface are detected by imaging the same area more than once. Here, we see several new dust avalanches on the slopes of ridges within the Olympus Mons Aureole. These changes occurred within six years. (Also see the animated GIF).

Dust avalanches create slope streaks that expose darker materials usually hidden below a lighter-toned layer. Cascading fine-grained material easily diverts around boulders or alters direction when encountering a change in slope (see the top right corner of the first close-up). The dark steak in another close-up is approximately 1 kilometer in length that we didn’t see in a previous image. Past avalanche sites are still visible and fading slowly as dust settles out of the atmosphere and is deposited on the dark streaks over time.

We also see boulders and their shadows that are a meter or greater in size. Movement of any of these boulders down the slope could trigger future avalanches.

Written by: Jennifer Newman, Eric Pilles, Sarah Simpson, Alyssa Werynski, Livio Tornabene (narration: Tre Gibbs)  (23 July 2018)
 
Acquisition date
13 May 2018

Local Mars time
15:24

Latitude (centered)
22.701°

Longitude (East)
214.316°

Spacecraft altitude
283.3 km (176.1 miles)

Original image scale range
56.7 cm/pixel (with 2 x 2 binning) so objects ~170 cm across are resolved

Map projected scale
50 cm/pixel and North is up

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Equirectangular

Emission angle
0.3°

Phase angle
53.8°

Solar incidence angle
54°, with the Sun about 36° above the horizon

Solar longitude
174.8°, Northern Summer

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North azimuth:  97°
Sub-solar azimuth:  351.3°
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POSTSCRIPT
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.