Its magnitude is 8.2. That is big... great earthquake sized and a tsunami is a distinct possibility according to the Pacific Tsunami Warning Center.
If a tsunami was produced people distant from it can still be warned, but it is already to late for people near the epicenter. Sadly, they were to close to be warned.
News on msn says no waves have yet developed. And it's been hours and hours. The warning system in Thailand did go off apparently, to warn and evacuate residents. I guess that's a good sign!