Fifteen years ago today, a Magnitude 9.2 earthquake struck off the west coast of Sumatra, producing the single-most devastating tsunami in recorded history. The tsunami that swept across the Indian Ocean killed more than 230,000 people and left more than 1.7 million homeless.
The megathrust earthquake initiated from the Sunda trench subduction zone off the west coast of Sumatra.
This devastation is a strong reminder that Washington state is also vulnerable to this type of event. Closer to home, other reminders are tsunami deposits, drowned shorelines, and buried trees from the 1700 A.D. Magnitude 8.8–9.2 megathrust earthquake along the Cascadia Subduction Zone. These clues have been located in numerous places along the Washington, Oregon, California, and Vancouver Island coasts.
Planning for tsunamis here
The Washington Geological Survey, is helping Washington communities identify how they are vulnerable to similar tsunami events and how they can craft innovative strategies for dealing with those threats.
When an earthquake hits, scientists expect a tsunami to land on Washington’s coast within 15 minutes of the initial strike. Two hours and 30 minutes later it is projected to hit the Tacoma waterfront after passing through the Strait of Juan de Fuca.
We’ve put together tsunami evacuation maps and a detailed video simulations illustrating the path, intensity, and effects on surrounding areas the next Cascadia Earthquake-induced tsunami is expected to have.
We’ve also put together walk maps to help you know in advance how long it should take to walk to safety in many Washington communities.
What we need to know!
Below is a list of preparedness tips, resources, and helpful information to make sure you’re ready when you feel the earth shake.
- Be informed: sign up for text alerts from local government and emergency alert stations. Look for signs when you visit coastal cities.
- Know your surroundings: if you are near the coastline, know where you can evacuate to higher ground.
- Know your evacuation route: if possible, identify multiple evacuation routes in case one is not accessible. You can check for evacuation routes in your area here.
- Plan ahead: if you are visiting the coast, ask your hotel staff what their evacuation route is. Likewise with schools, ask what their evacuation plan is—a route to higher ground or vertical evacuation as seen here.
- Have a communication strategy: develop a way to communicate with your family to ensure they are safe should you be separated. Choose a meeting spot on high ground and practice getting to that spot in various conditions.
- Preparedness packs: put together emergency bags for your family and pets to take when you evacuate. It is recommended to stock the bag with 2-weeks worth of supplies.
- Prepare all locations: place a preparedness pack in your car, at work, at school, on your boat, and in your house to ensure you are ready no matter where you are.
- Maritime preparedness: if you are on a boat out in the water, move to depths of 180ft. Wait until you are given the all clear from officials to come back to the harbor. If you are in the harbor, exit your boat and move to higher ground.
- Stay updated: purchase a battery operated radio to receive updates from NOAA weather radio station.
- Pass it on: share your knowledge with friends and refer them to these links for more detailed information.