Histogram of the mass fraction of boulders ejected with speeds above the target escape velocity (v >  v_esc), for targets with different configurations of boulders. m_b is the boulder mass in each bin, and ∑M_b is the total mass of ejected boulder material above v >  v_esc. The velocity data are discretised into 20 cm s⁻¹ bins. The total mass of boulder material ejected is shown in green, and the mass of ejected boulder material that has been fragmented (D >  0.5) is shown in yellow. In each panel we show the ratio of the sum of ejected boulder mass to the sum of total ejecta mass (ratio = ∑M_b/∑M).