There was just a M8.7 in the Indian Ocean rather far west of northern Sumatra, where the M9.2 occurred in December 2004 with deadly tusnami. But, and just in the last couple of minutes they put up a focal mechanism, this is not a subduction quake: it is strike-slip and relatively far west of the subduction zone. This is likely a hugely unusual quake. Maybe the magnitude will be downgraded. If it stays M8.7, I think it is the largest recorded strike-slip quake in instrumental history. If it broke only the upper 20 km or so, it would have to be incredibly long (1000 km? much more?) to be M8.7.

There is a tsunami watch for the Indian Ocean. Strike-slip earthquakes should not cause anything like the 2004 tsunami.

I woke up wide awake worrying about something unrelated, probably just before the quake (I woke up at 12:30 AM Pacific). But, I often wake up avery couple of hours.

I'm in Goleta California, next to UCSB.

OK, now I have to stay up more and see what is going on

Chris

• Indian Ocean Great quake