Dan Spires wrote:
I see this as working hand-in-hand with item 1, simple dust buildup and collapse. Merely a breeze to topple the buildup, so it would not need to follow a specific wind direction.

Alex writes:
Perhaps, but simple oversteepening on slopes, combined with low angles of internal friction (10-30 degrees) for plausible low-cohesion Martian airfall dust deposits, is sufficient without an external force.

Dan Spires wrote:
Wondering, though. What about craters? Are the streaks shown to be all around the bowl, or are they heavily concentrated in one section, possibly due to prevailing winds dropping additional particles, or knocking the grains loose?

Alex writes:
As best as I can tell, the distribution of orientations (as well as local/regional clustering) is essentially random, without a preference towards either of the two prevailing aeolian regimes under the current GCM's.

Alex R. Blackwell
University of Hawaii