Fig. 2. Pattern of internal and surface failure regions of cohesionless rubble piles.
a–c Dynamical internal slopes over a cross-section and surface slope map at the critical spin period Tcrit for simulations with three friction angles ϕ, respectively. The surface regions where material can be lofted are marked with negative slopes (the bluish areas). Regional failure is initiated when the local dynamical internal/surface slope exceeds the value of ϕ, which determines the failure behaviours as indicated on the top of each panel. The dynamical internal slope are calculated based on the averaged-stress analysis using representative volume elements (the patches shown represent the elements in these cross-sections), and the dynamical surface slope are derived based on the rubble-pile alpha-shape model (Methods). Source data are provided as a Source Data file.