Dust Avalanches Triggered by Impact Event
NASA/JPL/University of Arizona
Dust Avalanches Triggered by Impact Event
PSP_002764_1800  Science Theme: Impact Processes

Mars Global Surveyor imaged Mars from 1997-2006, and observed nineteen spots in dust-covered regions that darkened at various times, and that correspond to very recent-looking impact craters.

The craters are much smaller than the dark spots; the darkening is thought to be due to an atmospheric blast or high winds associated with the event which removed or redistributed the bright dust.

HiRISE has been re-imaging these locations, revealing many new details. In several locations the dark spots contain many dark streaks on topographic slopes. These dark streaks trend downhill, and the images reveal that a thin surface layer has been removed. These are interpreted as dust avalanches, which are common over dusty slopes of Mars.The dark streaks mark the most recent avalanches, which are often only a few years or decades old.

Visible here in the dark region is the densest concentration of dark streaks ever seen on Mars. Possibly these dust avalanches were triggered by the impact event, either from the atmospheric blast or from seismic shaking when the asteroid fragments struck the ground.

Written by: Alfred McEwen   (4 June 2007)

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Acquisition date:27 February 2007 Local Mars time:15:41
Latitude (centered):0.001° Longitude (East):226.886°
Range to target site:266.3 km (166.4 miles)Original image scale range:26.6 cm/pixel (with 1 x 1 binning) so objects ~80 cm across are resolved
Map projected scale:25 cm/pixel and North is upMap projection:Equirectangular
Emission angle:4.5° Phase angle:60.0°
Solar incidence angle:55°, with the Sun about 35° above the horizon Solar longitude:191.5°, Northern Autumn

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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.