Monday, March 29, 2010

Rotational Landslides or Slumps Along Walls of Bahram Vallis

Bahram Vallis is a narrow-winding valley (20-22 North, 301-304 East) that terminates at the circum-Chyrse Basin on Mars.

The valley has numerous circular to sub-circular alcoves along its slopes, some with large deposits directly below on the valley floor. These features are evident from earlier image datasets of Mars including THEMIS, MOC, and HRSC, and are indicative of mass-wasting processes that have occurred along the valley walls.

A portion of the valley was imaged by the HiRISE camera at approximately 30 centimeters/pixel resolution in a location with both alcoves and valley floor deposits. Several features are apparent: a well-defined circular crown and main scarp, tensional cracks along the crown margins, and a well-defined accumulation zone with slump deposits.

The general appearance of these landslides is similar to terrestrial rock and/or loose earth rotational landslides. The Bahram landslides are also different from other well-documented landslides on Mars, such as those in the Valles Marineris canyon system that have lobate forms and longitudinal and/or transverse ridges on their surfaces. Future study of these landslide deposits will incorporate elevation data from the digital topographic model to assess the stability of valley walls using standard earth geotechnical models.

Credit: NASA/JPL/University of Arizona/USGS

Note: While doing research for the various links in this post, I came across this short flyby animation of the Bahram Vallis that uses HiRISE data. Enjoy!

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