Tsunami Warning!

It’s 8AM in northern Chile. As people on shore
begin their day, twenty-five kilometers
below the Earth’s surface, tectonic plates shift
in a massive earthquake. Immediately seismographs
detect this activity and computers
begin determining the quake’s epicenter
and magnitude. Within seconds people
feel the powerful shaking, strong enough to knock them to
the ground and damage buildings. This is a warning sign
of a possible tsunami. Without waiting for an
official tsunami warning, people start evacuating
to high ground, or the top floors
of tall buildings. A tsunami is a series of
potentially deadly ocean waves created by a powerful
undersea earthquake that can last for hours. 76% of the world’s
deadly tsunamis have occurred in
the Pacific Ocean. In 1960, a magnitude 9.5 quake off Chile’s central
southern coast, caused the tsunami that claimed
lives across the Pacific Ocean. Sensor data from
a global network is continuously transmitted
to the tsunami warning centers in Chile and Peru, as well as the Pacific Tsunami
Warning Center (PTWC) in Hawaii, where duty officers assess
the tsunami threat. The PTWC serves as the
operational headquarters for the international tsunami
warning system for the Pacific. The PTWC analyzes data and
issues tsunami threat advice for countries throughout
the Pacific Ocean. This information is vital for nations that are too far away
to feel the earthquake, but may be in the
tsunami’s path. The Pacific Tsunami
Warning and Mitigation System, is coordinated under the UNESCO Intergovernmental
Oceanographic Commission. It covers forty-six countries
in the Pacific Ocean and its marginal seas,
and was started in 1965 in response to the deadly
Chile tsunami of 1960. Early readings indicate the earthquake is at least
a magnitude of 8.8. and located off of
Chile’s northern coast. Later readings will
ultimately show it to be 9.5. This shallow undersea earthquake
creates a giant tsunami. Officers at the tsunami warning
centers in Chile and Peru issue tsunami
early warnings to all coastal towns
in the vicinity. The tsunami is
expected to arrive in as little as ten minutes in
Chile, and 45 minutes in Peru. Emergency responders
and news organizations act on the tsunami warnings and immediately announce
the evacuation. The PTWC completes its
initial earthquake analysis, and issues the first
tsunami threat bulletin, to all countries in the
tsunami’s predicted path. Officers from the PTWC call
the tsunami warning centers, to advise them on
their forecast. Some countries have their own tsunami
forecasting capabilities, while others rely on the PTWC’s
tsunami advisory services. Early warnings with
accurate tsunami forecasts, depend on contributions
from all countries, and the free and open sharing of real-time seismic
and sea level data. The PTWC forecasts that tsunami
waves of five meters or more will arrive in Hilo, Hawaii,
and Samoa in fourteen hours, and in Japan in 22 hours. The PTWC issues its
second bulletin with predicted wave
heights to all countries. The first of many tsunami
waves strike the Chilean coast. Fortunately due to regular
tsunami evacuation drills, and the early response, no one was in the danger zone
when the waves crashed ashore, there are no casualties. The PTWC reports on
observed waves for Chile, the third wave was the largest, and arrived thirty
minutes after the first. The PTWC monitors
tsunami threats, and advises countries
across the Pacific. Each nation issues
its own tsunami warning, and guides its own
emergency response. In Samoa and Hawaii
tsunami warnings are issued, and evacuation begins. Local authorities quickly
spread the word about the tsunami alert, and carry out
their response plans. The PTWC continues monitoring and issuing updated
bulletin and reports. Fourteen hours
after the earthquake, the tsunami strikes
Hawaii and Samoa. Thanks to status bulletins
and advice from the PTWC, these areas have
fully evacuated. The natural disaster causes
extensive property damage, but no lives are lost. The tsunami sweeps
across the Pacific ocean, tsunami warning centers on
the western side of the Pacific issue warnings in preparation. While emergency management
authorities in those countries determine areas of evacuation, Hawaii and Samoa have
canceled their warnings, and deployed search
and rescue teams. Chile and Peru begin the
process of digging out from their earthquake and
tsunami damage. This scenario was fictional
and meant to illustrate how all of the elements of the
Pacific Tsunami Warning System work together to save
lives across the Pacific in the event of a tsunami. The Pacific Tsunami Warning
System is an evolving system that saves lives. Only with ongoing
long-term support can the PTWS stand ready to warn
nations in time to take action. No one knows when and where the
next deadly tsunami will occur, but we must remain prepared, for it could happen today, or fifty years from now.

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