Kerry mentions that it ruptured into the mantle; that partly explains how it could be so large. I was posting that it was the largest strike-slip quake on record but your link is the first time I've seen that written.

There is still a lot of geology I would like to know about these quakes. For example, the slip distribution will be interesting: there must also have been some of the highest slips ever on a strike-slip earthquake.

Chris