She said "Sydney" was mentioned in the thread; whether that was the city, or a screen name, she couldn't recall.
After the Q/A period, I'd would veture this guess: inbound flight might've hit hard turbulence, and the all-hands was put out to get to your seats, return your trays upright, yadayada. I am not thinking this is a detonation scenario.
Cal's thread to the FAA reveals that all West COast terminals are showing green, for normal ops. If there had been an in-flight, the traffic control betwork would be reacting by now.
I'm hoping to hell this is a false alarm.