  We present a framework to study regolith segregation on rubble-pile asteroids
(self-gravitating granular aggregates) due to seismic shaking induced by
impacts sustained during their lifetimes. We first relate the amplitude and
frequency of surface vibrations to the location and severity of an impact, and
the rubble body's geometry and bulk properties. For clarity, the body is taken
to be an ellipsoid with size and spin close to that of Itokawa, although other
asteroids are also easily incorporated. We then model the body's collisional
history stochastically given the variability in the impact activity on an
asteroid. Finally, we utilize discrete element simulations to investigate the
regolith's response to impacts. In these simulations, in any sample collisional
history, every time an impact occurs, a bin filled with a grain mixture and
located at the region of interest on the asteroid is vibrated at that impact's
associated amplitude and frequency. Utilizing this framework we find that
impact-driven seismicity is sufficient to drive size segregation on small
rubble-piles, but the segregation quality depends on several aspects, e.g.
total impact energy supplied, placement of the region of interest, bulk wave
speed, and seismic diffusivity.
