[zh3]

I imagine the search and rescue effort have checked the seismograph/ocean sounds/other networks, AIUI an implosion at depth makes quite a bang, so not detecting one would be a positive.

[ra]

Yeah, and you would have thought that in calm weather there would have been something to see on the surface. I hope they're OK.

[mannykannot]

It is a notoriously foggy area. I hope it at least has a radar reflector.