Collision probabilities for 30–40 orbital periods for model a1 (upper left), model b1 (upper middle), and model b2 (upper right) as well as for 50–60 orbits for model a1 (lower left), model b1 (lower right), and model b2 (lower right). We show the plot radius (in au) versus the probability for an event (in percent) for disruption and merging for methods m1 and m2 (explained in the text).