Western Washington lies at the point where two of Earth's large crustal plates meet. The zone of contact between the plates is the Cascadia fault, and the collision of these plates produces volcanoes and earthquakes. The largest earthquake known to have occurred in the continental U.S. hit the Pacific Northwest in 1700, had a magnitude of between 8 and 9 on the Richter scale, and lasted for three to five minutes. Earthquakes as large as magnitude 7.5 are expected in this region at a rate of about two every 130 years. Five events greater than magnitude 6.0 have occurred since 1909.
7.1 During an Earthquake
Remember to duck, cover, and hold.
- Duck: Get down on the floor at the nearest protected place.
- Cover: Get under a sturdy desk, a table, or other furniture. If that is not possible, seek cover against an interior wall and protect your head and neck with your arms. Avoid danger spots near windows, in areas where chemicals are in use or stored, in doorways, or near tall furniture such as bookcases, book shelves or filing cabinets.
- Hold: Hold on tight, because the shaking may move the desk, table, etc., away from you.
7.2 After an Earthquake
- Be prepared for aftershocks.
- Check for injuries.
- Check the building for safety.
- Remain inside the building unless it is clearly unsafe (fire, gas leak, hazardous materials, structural concerns) or you are directed to evacuate.
- Avoid using the telephone except for true emergencies; keep the lines free for essential emergency calls. Telephone circuits are often overloaded after an earthquake as people call their friends and loved ones, and some true emergency calls cannot be completed as a result.
- Open cabinets or closets slowly and carefully; contents may have shifted and might tumble onto you or to the floor when doors are opened.
- If you do need to evacuate the building, be aware of and avoid stepping near downed power lines, unstable structures, and broken glass.