  We consider how an impact generated seismic pulse affects the surface of an
asteroid distant from the impact site. With laboratory experiments on dry
polydisperse gravel mixtures, we track the trajectories of particles ejected
from the surface by a single strong upward propagating pressure pulse. High
speed video images show that ejecta trajectories are independent of particle
size, and collisions primarily take place upon landing. When they land
particles are ballistically sorted, as proposed by Shinbrot et al. (2017),
leaving larger particles on the surface and smaller particles more widely
dispersed. A single strong pulse can leave previously buried boulders stranded
on the surface. Boulder stranding due to an impact excited seismic pulse is an
additional mechanism that could leave large boulders present on the surface of
rubble asteroids such as 162173 Ryugu, 101955 Bennu and 25143 Itokawa.
