A tsunami (pronounced "soo-nah-mee") is a series of waves
of ***extreme***ly long wave length and long period generated in a
body of water by an impulsive disturbance that vertically displaces
If an earthquake in Alaska generated a major tsunami, Alaskan shores
would be flooded within
15 minutes, while the coasts of Hawai'i would be hit within 5 hours
of the event. The Alaskan
and Pacific Tsunami Warning Centers (ATWC and PTWC) would issue
warnings, based on seismic data alone. With confirmation, the PTWC
might issue a Pacific Basin-wide warning.
Even at this time, the Centers would have only a rough idea of the
potential size of the tsunami. They would receive no further information
until the tsunami reached Midway Island (about 3
hours after the earthquake) or the west coast of the US (4 to 5
hours after the quake).
Hawai'i emergency managers would have only about an hour and a half
to adjust their plans.
Hawai'i has been affected by at least 6 local tsunamis since the
mid 1800's. In 1975,
a magnitude 7.2 earthquake near the southeast coast of Hawai'i produced
a large tsunami with wave heights of at least 20 feet and in one
area nearly 45 feet. $1.5 million in property damages and two deaths
were attributed to this local Hawai'ian tsunami.
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