Interactions between complex craters and the lunar crust: Analysis using GRAIL data

Abstract

A high-resolution gravity map over the entire lunar surface has been derived from data acquired by the Gravity Recovery and Interior Laboratory (GRAIL) mission. Soderblom et al. (2015) showed that crater Bouguer gravity anomalies scale with crater diameter and porosity for craters in the lunar highlands. Here we extend this study globally, examining complex craters in each of the three lunar terranes: highlands, maria, and the South Pole-Aitken basin. We find that craters within South Pole-Aitken basin and in the lunar maria have statistically different Bouguer anomalies from those in the lunar highlands. These differences are best explained by differences in crustal porosity among the three terranes. Though there is still much unresolved scatter in the data, we find that no other lunar material properties (crustal thickness, density gradient, etc.) are able to improve our model fit to the data.