posted on Feb, 21 2006 @ 05:44 PM
It's difficult to tell specifically how active Martian Crust still is, but from these two fine .pdf's you can read some-what technical material
about Crustal mechanics on Mars.
Lateral extension of topography to extrapolate Crustal thickness
Both of these discuss well the thickness of the Martian crust with the thinnest section being the Northern Hemisphere having about a thickness of
Which is significantly thin; but not thin enough (probably) to have Plate tectonics.
However it is still interesting and very informative.