If it happened around noon, all the scuba boats were out, I imagine that the wreck I've dove many times is trashed, had the chance to dive it again a few weeks ago, maybe I should have.
I hope the airport is ok, its in the far north of the island, but very close to the sea.
Thailand dodged a bullet when I was there over thanksgiving, a typhoon was bearing down on Koh Tao and Samui, but it turned north and dumped rain over a droughed area in the Thai/Burma border area.
The death toll is going to be very high I am afraid.