Brian, nice. But, you will likely have to make the seafloor go away to be able to see through to the 3D hypocenters.

One thing I did (but using software that was made for that kind of thing) is an animation through the relocated seismicity of Santa Monica Bay as a cross section. The cross section was a couple of km thick (say, 2 km) and the front and back of the cross section volume was sliding through. Because of the larger scale of Japan, you might do a larger volume, for example, 10 km-thick.

Since you don't need to color code for depth on a cross section, could color code for days after (or before) main shock.

Chris