[Island Chris]

The area of the quake had many foreshocks, including a M6.7 on March 16, 2014 (2 weeks ago). That M6.7 had foreshocks. The M6.7 had a gently NE-dipping plane, so likely on or associated with the subduction megathrust. The dip direction of the M8.2 is just a bit north of east, so pretty different, but when a fault is that flat, maybe the dip direction is not really such a difference in orientation (plus, the focal mechanisms may be a bit off, or the rupture of one or both of them could be complex).

A reminder that the Tohoku (Japan) M9.0 had a M7.4 foreshock a few days ahead.

Chris