Shock effects from a large impact on the moon

Abstract

The paper calculates the shock and shear deformation-induced internal energy distribution associated with a major basin-forming hypervelocity meteorite impact on the moon. The Hageman and Walsh formulation of the axisymmetric two-dimensional conservation equations in finite difference form is used, and the flow field induced upon impact of an iron meteorite traveling at 15 km/sec with a gabbroic anorthosite lunar crust is calculated for sequential time steps over a grid of hoop-shaped zones fixed in space. If an energy of 5 times 10 to the 32nd power ergs for the projectile energy is required to excavate a basin of Imbrium size, than a flow field of approximately 210 km in radius approximately 19 seconds after impact is indicated. The meteorite residue, the melt, and the ejecta are discussed, and the results are compared with the Gault and Heitowit (1963) formulation.