Japan Earthquake, March 2011, MW=9.1

I heard about this earthquake last night about 10:30 PM. Initially the magnitude estimate was lower, but the USGS moment (2.8e29) gives MW=8.9. The Global CMT Project moment (6.03e29) gives MW=9.1.

The following is a screen capture from Google Earth, showing aftershock locations. Yellow colors are foreshocks. The aftershock zone is about 180-200 km wide, 400-450 km long. A zone that is 200 x 400 km, with the USGS moment, implies mean slip of 9 m. That would be 100 years of slip accumulation based on the convergence rate shown on this map.