Obtaining Average Crustal and Uppermost Mantle Properties for Planetary Models of Mars

Abstract

After more than 4 Earth years (∼1450 sols) of operations on the martian surface monitoring the planet’s ground vibrations, the InSight’s seismometer is now retired. Throughout the mission, analyses of body waves from marsquakes and impacts have led to important discoveries about the planet’s interior structure of the crust, mantle, and core [1-5]. Recent detection of surface waves, together with gravimetric modeling enabled the characterization of crustal structure variations away from the InSight landing site and showed that average crustal velocity and density structure is similar between the northern lowlands and the southern highlands [6-7]. These new constraints obtained by surface wave measurements provide an important opportunity to refine and verify our previous radially symmetric models of the planet’s interior structure. As part of this effort, we obtain the average crustal and uppermost mantle velocities of Mars using Rayleigh waves orbiting the planet multiple times. These higher-orbit Rayleigh wave observables independently constrain the average crustal and uppermost mantle velocities, and crustal thickness, which are found to be consistent with previous InSight studies. Successful incorporating of these velocity constraints into the existing joint inversion framework used for modeling body wave travel times [8], geophysical [9], and geodynamic parameters [10] will improve the current reference 1D interior models of Mars.