An earthquake is a sudden, rapid shaking of the ground caused by the shifting of rocks deep underneath the earth’s surface. Earthquakes can cause fires, tsunamis, landslides, or avalanches. While they can happen anywhere without warning, areas at higher risk for earthquakes include Alaska, California, Hawaii, Oregon, Puerto Rico, Washington, and the entire Mississippi River Valley.

Drop (or Lock)
Wherever you are, drop down to your hands and knees and hold onto something sturdy. If you’re using a wheelchair or walker with a seat, make sure your wheels are locked and remain seated until the shaking stops.
Cover
Cover your head and neck with your arms. If a sturdy table or desk is nearby, crawl underneath it for shelter. If no shelter is nearby, crawl next to an interior wall (away from windows). Crawl only if you can reach better cover without going through an area with more debris. Stay on your knees or bent over to protect vital organs.
Hold On
If you are under a table or desk, hold on with one hand and be ready to move with it if it moves. If seated and unable to drop to the floor, bend forward, cover your head with your arms and hold on to your neck with both hands.
For more information, please refer to this great article at Ready.gov.