Initially the system was based on seismic data plus inputs from a series of tide gauges that sent information about water levels around the ocean to warning centers in Hawaii, Japan, and elsewhere ...

From the area where the tsunami originates, waves travel outward in all directions ... Washington, Alaska and Hawaii. Earthquake-induced movement of the ocean floor most often generates tsunamis.

The last deadly Hawaii tsunami was in 1975, when an earthquake off the coast of the Island of Hawaii generated large waves within seconds that killed two people. In 1960, a tsunami resulting from ...