  We consider the dynamics of a particle confined in a double well potential
which is subjected to a periodic drive. In the case of deep and well separated
wells, we find that by adjusting the parameters of the drive we can generate,
to a very good approximation, a volcano potential. The quantum dynamics in this
volcano potential is studied by a variation of what can be called a generalized
Ehrenfest's theorem. We find that the coupling of the mean position and the
width of the wave packet in this dynamics causes the particle to escape from
the central well in accordance with the fact that the volcano potential only
supports resonance states.
