Tsunami waves travel at speeds of 300-600 miles per hour (483-966 km/hr), and the first wave may not be the largest one. Although most tsunamis are caused by earthquakes in oceanic and coastal regions, they can also be triggered by underwater landslides and submarine volcanic eruptions that are powerful enough to displace the surrounding water.

Related Hazards

• Powerful waves that approach coastlines at high speed
• Moving debris caught up in the flow of water
• Flooding of coastal areas

Precautions

• If you are near the coast when an earthquake strikes, seek higher ground immediately.
• Consult tsunami evacuation maps to find out if you live, work, or go to school in a tsunami inundation zone.
• Be familiar with tsunami warning signs and sirens, and know their meaning.
• Have an evacuation plan and disaster supply kit ready, including a radio and batteries.
• Have a family communication and meeting plan prepared.
   

What to Do During a Tsunami

• Listen to local radio stations for official announcements and instructions.
• Evacuate if advised or ordered to do so.
• Stay away from beaches and all coastlines.
• Wait for the “all clear” announcement before returning to coastal areas.

Resources

NOAA's Tsunami.gov

International Tsunami Information Center

Tsunami Awareness Program - Hawaii