This is amazing video (with sound) of the recent explosive eruption of Mount Tavurvur in Papua New Guinea, taken by Phil McNamara. Few people in the world will ever get to witness something like this, let alone capture video of it. Note the shockwave that travels along the ground as well as through the cloud layer. I have no idea how large the boulders are that were ejected, but I suppose one could roughly estimate how high they reached by timing how long it took them to fall.