They increased the magnitudes of the largest aftershock from low 7 range to M7.9. It was 30 minutes after the main shock. It was also near the southern part of the present aftershock zone and is large enough to have ruptured a rather large part of the southern subduction zone. It is a subduction earthquake and likely contributed to the tsunami (although must have been a far smaller contribution).

I talked to Mark Legg on the phone yesterday and he had been observing the tsunami as it arrived in some "rivers" and harbors in southern California. He said that the largest part of the tsunami arrived long after the first part; in the (late?) afternoon. He also said that he could still see small tsunami motions 48 hours after the quake. The NOAA animation of the tsunami still showed the entire Pacific disturbed 24 hours after the quake.

Chris

• M7.9 March 11 aftershock