Complex Lunar Craters Mapped by High-Resolution GRAIL Gravity Data

The Gravity Recovery and Interior Laboratory (GRAIL) mission [1] has successfully completed its three-month primary mission to directly measure lunar gravity. These data are of sufficient resolution and accuracy to address problems that have traditionally been in the realm of surface geologists. Herein, we report on an investigation of the subsurface structure of complex lunar impact craters and their associated continuous ejecta blankets using the GRAIL gravity data in conjunction with topography derived from Lunar Orbiter Laser Altimeter (LOLA) data [2]. We use these data to understand the initial state of the brecciated and fractured zone associated with complex crater formation and its dependence on crater size [3,4], the subsequent evolution of these complex craters, and the bulk density of the ejecta blankets associated with them. [1] Zuber, M., 37th COSPAR Scientific Assembly, (2008) [2] Zuber M. T. et al., Space Sci Rev 150, (2010) [3] Pilkington, M. and R. A. F. Grieve, Reviews of Geophysics 30, (1992) [4] Melosh, H. J., Oxford Monographs on Geology and Geophysics 11, (1989)