Tuesday's earthquake shook the D.C. region, and the U.S. Geological Survey warns that aftershocks could be felt in the coming days. So what should you do when you feel one?
First, if you're inside, don't immediately run out, the Federal Emergency Management Agency recommends.
Writes FEMA, "if you are indoors, stay there until the shaking has stopped and you are sure exiting is safe."
Follow the drop-cover-hold on principle: "DROP to the ground; take COVER by getting under a sturdy table or other piece of furniture; and HOLD ON until the shaking stops."
If there is no table near you, cover your head and crouch in an inside corner of the building. Stay away from windows or anything that could fall, such as light fixtures.
Go outside only when you feel the shaking has stopped. "Research has shown that most injuries occur when people inside buildings attempt to move to a different location inside the building or try to leave," FEMA writes.
Viewer Kelly emailed WJLA with a similar warning, recounting the earthquake drills at her school. "In case of an aftershock people should know that evacuating buildings is not the best thing," she writes. "I was in elementary school when Seattle was hit with the 6.8 earthquake and we always had earthquake drills."
The FEMA website has more information on what to do after an earthquake - for example, be careful when you open cabinets as contents may fall on you.