Canie, not quite a hard as that. From the seismic waves, seismologists do source inversions. This one might be difficult because it was on multiple faults. For Tohoku Japan, there was pre-existing multibeam bathymetry, and repeat surveys could show displacements. But, in deep water the vertical resolution is likely better than horizontal. In Japan, the eastern coast moved 2 or 3 m which could be measured by GPS to help in the displacement models.

All less likely to work for the Indian Ocean quakes. But multibeam bathymetry may show offset seafloor features, and sure, send James down, or an ROV, or HW in Alvin or Nautile (she has been in both)

Chris