In article ,
says...

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But we see the same phenomenon in landslides in desert regions on the earth.
There is evidence that some large landslides will behave as a fluid due to
the creation of a layer of compressed air between the landslide material and
the ground upon which it is sliding. Such a layer acts like a lubricant
that reduces friction, and will allow the slide to behave as a fluid. In the
case of Mars, the air would consist of the CO2 atmosphere. Now, I am not
saying that water doesn't exist on Mars. Obviously it does, at least at the
poles. And of course, we have all seen some evidence that there may be
ground water, and/or frozen water in the subsurface. What I am saying is
that there are other explanations for the fluid appearance of these
landslides on Mars.

OK, George, I'll buy that. Now, explain to me how you get a landslide
on what appears to be topography that is extraordinarily flat for miles
and miles in all directions? As I mentioned before, there are no large
craters that would create these "splash" landforms as ejecta, at least
not in the right place to have caused the effects visible in the DIMES
images.

I'm not saying that water has flowed over or under this surface
recently. It may have been more than a billion years since water flowed
over this surface. But I believe it's very possible that water HAS had
a hand in the sculpting of the surface we're observing, even at very
high resolution.

Doug