Complex Crater Formation by Oblique Impacts on the Earth and Moon

Almost all meteorite impacts occur at oblique incidence angles, but the effect of impact angle on crater size is not well understood, especially for large craters. To improve oblique impact crater scaling, we present a suite of simulations of complex crater formation on Earth and the Moon over a range of impact angles, velocities and impactor sizes. We show that crater diameter is larger than predicted by existing scaling relationships for oblique impacts; there is little dependence on obliquity for impacts steeper than 45 degrees from the horizontal. Crater depth, volume and diameter depend on impact angle in different ways-relatively shallower craters are formed by more oblique impacts. Our simulation results have implications for how crater populations are determined from impactor populations and vice-versa. They suggest that existing approaches to account for impact obliquity may underestimate the number of complex craters larger than a given size by as much as one-third.

Automated summary

The study shows that compared to existing predictions for oblique impacts, crater diameter is larger; there is little dependence on obliquity for impacts steeper than 45 degrees; crater depth, volume and diameter depend on impact angle in different ways, with shallower craters formed by more oblique impacts.