  Seismic shaking is an attractive mechanism to explain the destabilisation of
regolith slopes and the regolith migration found on the surfaces of asteroids
(Richardson et al. 2004; Miyamoto et al. 2007). Here, we use a continuum
mechanics method to simulate the seismic wave propagation in an asteroid.
Assuming that asteroids can be described by a cohesive core surrounded by a
thin non-cohesive regolith layer, our numerical simulations of vibrations
induced by micro-meteoroids suggest that the surface peak ground accelerations
induced by micro-meteoroid impacts may have been previously under-estimated.
Our lower bound estimate of vertical accelerations induced by seismic waves is
about 50 times larger than previous estimates. It suggests that impact events
triggering seismic activity are more frequent than previously assumed for
asteroids in the kilometric and sub-kilometric size range. The regolith lofting
is also estimated by a first order ballistic approximation. Vertical
displacements are small, but lofting times are long compared to the duration of
the seismic signals. The regolith movement has a non-linear dependence on the
distance to the impact source which is induced by the type of seismic wave
generating the first movement. The implications of regolith concentration in
lows of surface acceleration potential are also discussed. We suggest that the
resulting surface thermal inertia variations of small fast rotators may induce
an increased sensitivity of these objects to the Yarkovsky effect.
