NOAA's National Weather Service

Tsunami Warning:

A tsunami warning is issued when a potential tsunami with significant widespread inundation is imminent or expected. Warnings alert the public that widespread, dangerous coastal flooding accompanied by powerful currents is possible a may continue for several hours after the arrival of the initial wave. Appropriate actions to be taken by local officials may include the evacuation of low-lying areas. People in the warned areas need to move to higher ground or inland and stay in a safe area until local officials give the "all-clear".

Tsunami Advisory:

A tsunami advisory is issued due to the threat of a potential tsunami that may produce strong currents or waves dangerous to those in or near the water. The threat may continue for several hours after the arrival of the initial wave, but significant widespread inundation is not expected for areas under the advisory. Appropriate actions to be taken by local officials may include the closing of beaches and the evacuation of harbors and marinas. People in the advisory area should head local official�s instructions to leave affected areas until given the "all-clear".

Tsunami Watch:

A tsunami watch is issued when a potentially dangerous, distant seismic event has occurred which may later impact the watch area with a tsunami. Be ready to take action if a tsunami warning or advisory is later issued.

Tsunami (Seismic) Information Statement/Bulletin:

A tsunami information statement is issued when an earthquake has occurred or a tsunami warning, advisory, or watch has been issued for another part of the ocean. In most cases, tsunami information statements are issued to indicate there is no threat of a destructive tsunami for the area. In international products, a tsunami information statement is called a tsunami information bulletin. Tsunami "seismic" information statements may be issued to share the earthquake information when the earthquake is so small that it is known that no tsunami threat exists.