Friday, August 31, 2012

Stability of Slopes

  With Curiosity on her way to Glenelg one of the potential hazards is slippage on a slope. The critical angle for stability on a slope is referred to as the angle of repose. It is connected with landslides and avalanches. For sand dunes and barchans which are formed by aeolian processes the steeper slope is the slip face and is inclined at the angle of repose. This angle also determines the slopes of sand volcanos and mud volcanos. It is possible that the slopes of Gale Crater were formed by these processes and that warming of the surface induced instabilities. Liquid water has greater mobility than ice and buoyancy forces will cause it to move to the surface. So in a period of warming one would expect more geological activity. It should also be noted that the ground temperature at Gale Crater is now near the melting point of water.
  Supplemental (31 Aug): The varying slopes in Gale Crater suggests the possibility of microclimates in the area which might be of interest.

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