You are here: Home > Complete Preparedness Library > Natural Disasters and Bad Weather > Tsunamis > Warning Signs of a Tsunami
Warning Signs of a Tsunami
  • A large-scale earthquake lasting for more than twenty seconds can be the precursor for a tsunami.  When a region is hit by an earthquake of large magnitude, you should be aware that coastal regions located near the earthquake’s epicenter could be hit by a tsunami.
  • A more immediate warning sign of a tsunami is the rapid and unexpected decline of water level, below what is normal during low tie.  This can happen for a few minutes before the coast is hit by a tsunami and is the only sign along coasts that are located too far away from the epicenter for the earthquake to be felt.
  • A tsunami can just as often occur without any warning signs.
  • The Seismological Society of America monitors these events at any time of day.  When a tsunami does occur, they try to give the earliest possible warning to the media in regions that are likely to be affected. 
  • The Communication and Traffic Services of the U.S. Coast Guard will also release maritime warnings in case of a tsunami.
  • When you become aware of a tsunami warning, seek higher ground if possible.