A Global Analysis of Crater Depth/Diameter Ratios on the Moon

On the Moon, the old anorthositic highland rocks and younger basaltic mare units show distinguishable differences in appearance. The craters on the lunar highlands and maria also show variation in morphological characteristics. We analyzed the crater morphologies on a global scale, based on our new global catalog of lunar impact craters (>1 km in diameter) with morphological information for each crater. We find that there is a global power-law relationship with an offset term between crater depth-to-diameter ratios and crater densities. Small craters (less than similar to 4 km in diameter) on the lunar maria are found to be deeper than those on the highlands, indicating differences in target properties and crater degradations. Furthermore, the depths of the deepest simple craters identified on the lunar maria and the highlands provide references that the mare basalts and highland upper megaregolith have thicknesses of similar to 2.3 and similar to 3.3 km, respectively. Plain Language Summary The lunar surface is divided into light areas called lunar highlands and darker areas called maria. The craters show variation in morphological characteristics on the lunar highlands and maria. The depth-to-diameter ratios reflect the morphological characteristics of craters. Global distribution of crater depth-to-diameter ratios in different diameter ranges are analyzed. We find that there is a global power-law relationship with an offset term between crater depth-to-diameter ratios and crater densities. Small craters (less than similar to 4 km in diameter) on the lunar maria are found to be deeper than those on the highlands, which indicates differences in target properties and crater degradations. Furthermore, the depths of the deepest simple craters identified on the lunar maria and the highlands provide references that the upper layer of the maria and highlands have thicknesses of similar to 2.3 and similar to 3.3 km, respectively.