Motion of boulders on each facet. (a) Boulder motion on facet number 152 for different diffusivity values: K = 1000 m² s⁻¹ (Simulation 2, dotted line with downward triangle), K = 2000 m² s⁻¹ (Simulation 1, solid line with square), and K = 3000 m² s⁻¹ (Simulation 3, dashed line with upward triangle). (b) Boulder motion on facet number 152 for different seismic efficiency values: η = 5.0 × 10⁻⁸ (Simulation 5, dotted line with downward triangle), η = 1.0 × 10⁻⁷ (Simulation 1, solid line with square), and η = 5.0 × 10⁻⁷ (Simulation 8, dashed line with upward triangle). (c) and (d) show the same comparisons as (a) and (b), respectively, but for facet 93. The markers indicate the final positions of the boulders 10 minutes after the impact. The inclined black lines represent the local surface slope.