Distant Tsunami: A tsunami generated by a major earthquake, originating more than 1,000 km or more than 3 hours from its source. Less frequent, but much more hazardous than regional tsunamis.
Local tsunami: A tsunami generated by an earthquake less than one hour from the coast. Most destructive tsunamis are local or regional.
Microtsunami: A low amplitude tsunami that is only observed instrumentally. Not easily detected visually.
Ocean-wide tsunami: See distant tsunami.
Recession: Drawdown of the seal level prior to tsunami flooding, exposing sea bottom, rocks and fish. This is a natural sign that a tsunami is approaching.
Regional Tsunami: A tsunami generally within 1-3 hours from its source. Most destructive tsunamis are local or regional.
Seismic sea wave: Another name for tsunamis.
Teletsunami: See distant tsunami.
Tsunami Advisory: Strong currents and waves that are dangerous to those in or very near water are possible. Take action. Stay out of water and away from beaches or waterways.
Tsunami All-Clear: Notice issued by local authorities when a tsunami warning is cancelled indicating to the public that it is safe to return to evacuated zones. Not the same as a Tsunami Warning Cancellation (TSW).
Tsunami Information Statement: An earthquake has occurred but there is no current tsunami threat.
Tsunami Warning Cancellation (TSW): The cancellation of a warning after damaging waves have stopped coming ashore and sea level readings indicate that the tsunami is below destructive levels. This is not the same as a Tsunami All Clear notice.
Tsunami Warning: Dangerous coastal flooding and possible currents is expected or is occurring. Prepare for flooding. Take action. Move to high ground or inland.
Tsunami Watch: A distant earthquake has occurred and a tsunami is possible. The area included in the watch is determined by magnitude of the earthquake. Be aware. Be prepared to act.
Tsunami: A series of ocean waves that travel at speeds averaging 450 mph, produced by earthquakes or underground landslides below or near the ocean floor.