Internal Structure and Properties of Mars

Theoretical physical models of the Martian interior are presented in the light of new and revised data and constraints. These models include thermal evolution, densities, and seismic wave velocities. The interior of Mars appears to be Earth-like in many respects. Although thermal models indicate that Mars has passed its peak of evolution it may still have an asthenosphere and may be moderately active tectonically. Mars has an Fe-FeS core with a radius of 1500-2000 kin. The mantle is enriched in FeO with an olivine composition of about FoTa. Theoretically determined seismic wave velocities are relatively well constrained in the mantle with upper-mantle P , velocities ranging from 7.64 to 7.80 km/sec. However, there are wide variations in Vp in the core dependent on composition. The shadow zone due to the core is larger than the Earth's.