The Great Washington ShakeOut - Get Ready!
Lots of resources at the link, even if you're not in the Evergreen State, let alone if your school or employer is not participating.
A tip: The old advice to seek safety in a doorway has gone by the wayside; while the door frame MAY be strong enough to resist collapsing, the door itself is going to swing back and forth...
Instinct may be to get the hell outside!!! Resist the urge: Running for the door -- which is likely to be unmanageable, see above -- will waste time that could be better used seeking cover inside. Plus, your footing will be unsteady, to say the least.