UPDATE: Tonight the Mayor’s Office of Emergency Management said there was a 10% chance of an aftershock within 24 hours and issued this advisory statement.

According to an email sent to Johns Hopkins University employees:

Aftershocks can occur in the first hours, days, weeks, or even months after a quake.

If aftershocks materialize, remember to:

• Stay away from glass, windows, outside doors and walls, and anything that could fall, such as light fixtures or furniture.

• If you evacuate a building, move as far away from that facility as possible.

For more information about earthquake safety, the Federal Emergency Management Agency (FEMA) offers these guidelines.