In 2004, a powerful tsunami washed over coastal areas in Southeast Asia, extending all the way to Africa’s west coast. The tsunami took more than 200,000 lives, and some people were never recovered or identified. Much of this loss might have been avoided had an effective emergency preparedness system been in place.
The 2004 tsunami may have been the most deadly in recorded history, but it was not the first – 25 of them were recorded in the 20th Century alone. And while many of them have happened in the South Pacific, tsunamis have been recorded all over the world, from Japan to Chile, from Italy to to the United Kingdom. New Zealand’s geologic record documents a tsunami 125,000 years ago,and written history documents these disasters as early as 1580 B.C. (following the Santorini volcano).
Until very recently, scientists have not been able to predict when and where a tsunami will strike, making emergency preparedness very difficult. Caused by earthquakes, volcanoes, and landslides on the sea floor, today we can make and educated guess about when they will happen after such an event.
Today, regions at high risk may use a tsunami warning system to warn people before the wave reaches coastal areas. Computer models are used to predict the time and location of impact Until now, the exact location where tsunamis will strike cannot yet be predicted. But once an underground earthquake occurs, an alert is sent to coastal communities that something could go in that direction. Emergency preparedness efforts are more likely to succeed when these alerts are timely.
The famous “Ring of Fire,” where many volcanoes have occurrred along the lines where tectonic plates meet in the Asian Pacific, was not adequately protected by an early warning system in 2004. This was a valuable lesson for coastal areas around the world, and scientists are working hard to prepare for future events in that area.
Emergency preparedness for tsunamis begins with early warning systems that include four elements: information, advisory, watch, and warning. When the system detects an underground earthquake, Hawaii’s Pacific Tsunami Warning Center releases the news to the effected communities. Because it is too early to predict the size, time, or location of the potential tsunami at this stage, a more general advisory will be delivered to likely targets. It may take hours from the siesmic event to the actual tsunami.
Where evidence suggests that a tsunami is likely but hasn’t been witnessed or verified, early warning systems issue a watch alerting populations to the likelihoood. Emergency preparedness plans dictate that, at this time, people in coastal areas should be alert and watch the sea for signs, like a quick receding of ocean waters, that a tsunami is on its way. A siren may be used to alert the people, anywhere from three hours before the event is expected. If the water does begin to recede, a mandatory evacuation will begin.
Once a tsunami has been seen and verified, they issue a warning with more detailed information about where and when the giant wave willh it. A siren will again alert people. Once a warning is issued, people should already be moving out of the danger zone. They can go to high ground or try to go farther inland, taking fresh water, food, and extra clothing with them as they go. Part of the emergency preparedness effort includes annoucements that will be made over the radio telling them when it’s safe to return.
The early warning system continues to work during and after the event. People will remain in the area to monitor the situation and to cancel the warning if the tsunami does not materialize.
World leaders now recognize how important emergency preparedness is to potential tsunami victims. They encourage community leaders to develop plans and conduct exercises so that they know how long it will take to evacuate vulnerable areas. They should also have current estimates on the number of people in the area so that they’ll know if people are missing after the crisis has passed.
