Overview: Earthquakes and Tsunamis in Alaska

The city of Kodiak following inundation by seismic sea waves caused by the 1964 Alaska earthquake. The small-boat harbor contained an estimated 160 fishing boats when the tsunamis struck, washing vessels into the heart of Kodiak. U.S. Navy

Introduction

Alaska experiences more earthquakes each year than any other state in the United States, and is located in one of the most seismically active regions in the world. There are about 20,000 earthquakes in Alaska every year (Alaska Earthquake Center). “Great” earthquakes (larger than magnitude 8) happen in Alaska on average once every 13 years, while magnitude 7 to 8 earthquakes occur on average once every year.

The second strongest earthquake on record occurred in Alaska on March 27, 1964, with a magnitude 9.2. The Great Alaska Earthquake of 1964 and its aftermath killed over 100 people, injured many more, and forever changed our understanding of earthquakes. Among the most devastating effects of earthquakes are tsunamis, which caused the majority of deaths in the 1964 Alaska earthquake. In Alaska, it is extremely important to understand earthquakes and tsunamis, their causes, the hazards they can produce, and what to do before, during, and after one of these events.

How to Report an Earthquake

If you feel a major earthquake, take the steps below first and report it only when you are safe. For a minor earthquake, report it on the USGS Earthquake Hazards Program website.

What You Should Do Before, During, and After an Earthquake

Before

• Be aware of earthquake-safe places in each building you occupy regularly.
• Develop a family plan.
  • Designate a safe place to meet after an earthquake in case you are separated from your family.
  • Designate a friend or relative out of town as a contact, who can be a clearinghouse for your family to report their condition and location after a disaster. Make sure everyone in your family knows the phone number.
  • Secure bookcases, pictures, mirrors, hot water heaters, large appliances, etc., to the wall.
  • Learn how to shut off gas valves, water, and electricity in your home.
  • Make and maintain an emergency supply kit that contains at least seven days worth of food, water, and supplies and that can be accessed easily.

During

• If you are inside when the shaking starts:
  • Drop, cover, and hold on.
  • Do not run outside—this increases the likelihood that you will be hit by falling objects.
  • Ideally, take cover under a large piece of furniture, such as a sturdy desk or table, or against an interior wall away from bookcases, heavy furniture, wall hangings, and appliances that could fall on you.
  • Stay away from windows.
  • Stay indoors until the shaking stops.
  • It is no longer recommended that you stand in a doorway during an earthquake. A doorway can fit only one person and does not protect you from falling and flying objects.
• If you are outdoors when the shaking starts:
  • Find a clear spot that is away from buildings, trees, power lines, streetlights, etc.
  • Do not stand! Drop to the ground and stay there until the shaking stops.
• If you are in a vehicle when the shaking starts:
  • Pull over as soon it is safe to do so, in a clear spot away from bridges, overpasses, power lines, trees, and stoplights.
  • Stay inside the car with your seat belt fastened until the shaking stops.
• If you are in a mountainous area when the shaking starts:
  • Be alert for falling rocks, snow, and other debris.

After

• Do not use elevators. If the building is damaged and you need to evacuate, use the stairs.
• Be prepared for aftershocks—follow the same safety protocols as the mainshock for each aftershock.
• Check yourself and others for injuries. Do not move seriously injured people unless they are in immediate danger of further injuries.
• Check for any safety hazards.
  • Gas leaks. If you suspect a leak, shut off the main gas valve.
  • Oil or propane tanks. Check that nothing is loose or broken.
    • Do not use lighters, matches, candles, or gas lanterns until you know there are no gas, propane, or oil leaks. Use battery-powered flashlights or lanterns.
  • Damaged electrical wiring. If you see any damage, shut off the power at the breaker box or control panel.
  • Hazardous materials. Clean up potentially hazardous materials and/or medicines that may have spilled.
• Look for structural damage in your home and get everyone out if it is unsafe.
• Listen to emergency broadcasts for updated emergency information.
• Stay out of damaged areas and buildings.
• If you were away from home, return only when local authorities say it is safe.
• Keep landline phones as clear as possible so they can be used for reporting emergency situations.
• Avoid driving after an earthquake if possible, for your safety and to keep streets clear for emergency vehicles.
• If you are near the coast, be prepared for tsunamis—follow instructions below.

What You Should Do Before, During, and After a Tsunami

Before

• Know if your home, workplace, or school is in a tsunami hazard zone.
• Check with local authorities to learn the safe evacuation elevation/areas for your region.
• Plan and practice evacuation routes from your home, workplace, school, or other frequently visited places that are in tsunami hazard areas.
• Designate a safe place to meet after a tsunami, in case you are separated from your family. Phone lines may be down following a tsunami.
• Make and maintain an emergency supply kit that contains at least seven days worth of food, water, and supplies and that can be accessed easily.

During

• If you are near the coast and you feel a strong earthquake where shaking lasts 20 seconds or more, evacuate to higher ground as soon as the shaking stops. You may not have enough time to wait and see if a tsunami warning is issued.
• Listen to a National Oceanic and Atmospheric Administration (NOAA) weather radio broadcast, Coast Guard emergency frequency station, or a local radio or television station for updated tsunami emergency information. Or look at the National Tsunami Warning Center.
• If a tsunami watch is issued, review evacuation plans, stay alert for more information, and be ready to move quickly.
• If a tsunami advisory is issued, stay away from the shore and harbors.
• If a tsunami warning is issued or you see signs of a tsunami, evacuate immediately to higher ground. Evacuate as high as you can go and as far inland as you can get, away from rivers. Evacuate at least to the level and distance recommended by local authorities for your area.
• When evacuating, take your emergency kit with at least seven days worth of food, water, and supplies.
• Take your pets with you when you evacuate.
• Do not watch a tsunami. If you can see the wave, you are too close!

After

• Check yourself for injuries and seek first aid if needed.
• If someone needs to be rescued, call professionals.
• Avoid disaster areas if possible to allow rescue workers to do their jobs.
• Keep phone lines as clear as possible so they can be used for reporting emergency situations.
• Return home only after you get the “all clear” from local officials. Tsunamis are a series of waves, and can continue for hours. The first wave is not always the largest.
• Use caution when re-entering buildings or homes because they may be damaged.

For more detailed information on earthquakes and tsunamis check out the Alaska Earthquake Center publication Are You Prepared for the Next Big Earthquake in Alaska?

For More Information

Earthquakes

• Alaska Earthquake Center (AEIC)
• American Red Cross Earthquake Preparedness Resources
• Federal Emergency Management Agency (FEMA) Publications
• The 1964 Great Alaska Earthquake—US Geological Survey (USGS) Publication
• U.S. Geological Survey (USGS) Earthquake Hazards Program

Tsunamis

• NOAA National Tsunami Warning Center
• International Tsunami Information Center
• NOAA TsunamiReady program
• American Red Cross Tsunami Safety Checklist

Videos

• Alaska Sea Grant: Ocean Fury: Tsunamis in Alaska
• San Diego County Office of Emergency Services: Tsunamis: Know What To Do!
• US Geological Survey: 1964 Quake: The Great Alaska Earthquake
• National Weather Service: videos (search “tsunami”)

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Last modified 6 November 2020, 10:27am AKST. For website issues, contact Alaska Sea Grant web coordinator.
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