Earthquake!

I was sitting here at my computer in my 11th floor apartment about an hour ago when everything shook for a couple seconds. The news says it was a magnitude 4.8 earthquake in the northeastern part of the country. (Those of you in California might not be so impressed, but this was pretty big for me.) I called my friends, and they felt it, too. People are chatting about it on the internet. The emergency alert system has had announcements on TV saying that it's nothing to worry about, not that I understand these announcements. I only know this because my friends told me. For all I know, they could be saying that North Korea is attacking and we should all find a nuclear fallout shelter immediately.

Here's what's on the Korean websites:

It made me realize that I have absolutely no idea what you're supposed to do in the event of a serious earthquake. I remember fire drills, tornado drills, and bomb drills in school, but I don't remember earthquake drills. Maybe I just have the drills confused. Was that what we were doing when we sat under our desks and covered our heads? What should someone who lives on the 11th floor do if there is a serious earthquake? Stay put? Run down the stairs? Sit under my table and cover my head? Stop, drop, and roll? Maybe those of you in California (or anywhere!) can help me out here.