FLOOD03837

• County: Statewide
• Basin: Statewide
• Title: Confronting Natural Disasters
• Date: 11/2/1987
• Prepared By: Natural Resource Council
• Floodplain - Doc Type: Educational/Technical/Reference Information

Tsunamis cause significant damage and loss of
life in many regions of the world. About 6,000
people have been killed by these destructive waves
in the past decade alone. In the United States, for
example, the tsunamis generated by the Prince
William Sound, Alaska, earthquake of March
1964 killed more than 120 people and caused
damage estimated at greater than $100 million
(1964 dollars), including extensive damage to the
town of Crescent City, California.
Manv other countries have been seriously af-
fected 'by both distant and locally generated
tsunamis. For example, the 1960 earthquake
(magnitude 8.6) near Concepcion, Chile, gener-
ated a tsunami that traveled across the Pacific
Ocean at about 800 kilometets an hour (500 miles
per hour) and caused significant property damage
and loss of life. The japan Sea tsunami of May
1983 caused approximately 100 deaths and exten-
sive property damage and flooding along the
northwest coast of japan. This tsunami was
particularly well-documented, and the rich data
set compiled from it will improve our understand-
ing of tsunami action.
The occurrence of disastrous tsunamis is a
major threat to 22 countries along the rim of the
Pacific, although disastrous tsunamis have also
been felt in Portugal, the Mediterranean, and
other parts of the world. Current technology, if
applied, can mitigate the destructive impacts of
tsunamis on lives and property. Protection against
tsunami run-up can be achieved by constructing
barrier walls and othet diversions, as has been
done in japan. But the cost of such projects and
their degradation of natural seascapes restrict
their use. Land use zoning of coastal areas may be
a less costly way to reduce economic losses from
tsunamis.
Saving lives through effective early warning of
tsunamis propagated in the open ocean is cer-
tainly possible today. However, among the 22
countries in the circum-Pacific region, only a few
have standard operating procedures for immedi-
ate evacuation or reliable, rapid communication
systems capable of receiving real-time warnings
from the Pacific Tsunami Warning Center. In
recent years, Chile, with technical assistance from
the United States, has significantly upgraded its
disastet preparedness and evacuation planning
efforts. The United States installed a prototype
nearshore tsunami warning system that is used to
trigger evacuations along the Chilean coast within

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Beached ships and twisted
vehicles littered the Seward,
Alaska, waterfront when
tsunamis - "tidal waves" -
devastated tht city in the wake
of the great Alaskan
earthquake of March 1964.
The town harbor and part of
the Alaska Railroad terminus
was carried into the sea in a
giant submarine landslide
during the quake, generating
tsunamis which swept back
into Seward. Several Alaskan
communities were subjected to
such double disaster.