New push for tsunami-alert system
Japan offers to help build one for the Indian Ocean.
TOKYO — The estimated 10,000 people killed on the shores of Indonesia no doubt were too close to the epicenter of Sunday's earthquake to be saved by a tsunami early-warning system like the one used in the Pacific Ocean today. But experts say that such a system could have warned people in Thailand, India, Sri Lanka, and on the African coast that the deadly waves were coming.
South Asian officials are calling for the creation of an Indian Ocean warning system, and Japan - home of the world's most advanced tsunami alert system - is offering to help build it.
While most systems can take several minutes to determine if a quake poses a tsunami threat, Japan has developed technology within the past year that can calculate the size, speed, and direction of a nascent tsunami within seconds.
"We know that a tsunami will occur if the [earthquake] magnitude is over 6.3, and that a tsunami will cause damage if it's over 7.0," says Yoshinobu Tsuji, an associate professor at the University of Tokyo's Earthquake Research Institute. "Even in the slowest case, the Japan Meteorological Agency can judge within five minutes if a tsunami will occur."
Japan has an extensive system of 300 earthquake sensors that operate around the clock to relay real-time information to six regional centers. Once a tsunami threat is identified, local government officials nationwide are alerted to sound evacuation alarms and broadcast information on radio and TV. Coastal towns can also shut water gates to prevent waves from heading inland via low-lying river networks.
One of the reasons Japan's system works, says Mr. Tsuji, is "because Japan spends a lot of money on information transmission." He estimates that the country spends $20 million annually on the alert system.
A tsunami that hit the island of Hokkaido in 1993 demonstrated that community education and early warning systems save lives. Though 239 died, casualties were significantly reduced thanks to a timely warning issued by the meteorological agency, and because residents fled to higher ground after feeling the initial temblor.
Along with the US, Japan is one of the founders of the International Coordination Group for the Tsunami Warning System in the Pacific (IGC/ITSU). Established in 1965 after a tsunami struck Alaska, the ITSU early warning system now covers 26 Pacific-rim nations.
"But because the Indian Ocean is separate from the Pacific, there is no information on tsunamis in that area," notes Tsuji. He says that at an ITSU meeting three years ago, the point was made that there was a need for an early-warning system in Indonesia. "The main sticking point for Indonesia was cost and upkeep," says Tsuji.
In June this year, ITSU recognized that a significant threat of both local and distant tsunamis existed in the southwest Pacific and Indian Oceans and recommended that a group be set up to look into tsunami warning devices for countries in the region.
Experts say the establishment of a regional center capable of acquiring and analyzing both seismic and sea-level data would require a reliable high-bandwidth Internet connection as well as highly trained staff. "Putting in the sensors is the easy part," Harley Benz of the US Geological Survey in Golden, Colo. told the Associated Press. "The difficult part would be coordination between emergency response agencies in the region."
Reid Basher of the United Nation's Platform for the Promotion of Early Warning (PPEW) in Bonn told Reuters Tuesday: "The international community has to move ahead and build global systems to avoid a repeat of what has happened in Asia this week." He said that would now be a key topic at the World Conference on Disaster Reduction on Jan. 18 in Kobe, Japan. "It is easy to be wise after the event, but we must remember that the Indian Ocean has not had a major tsunami for over a century," said Mr. Basher.
As a nation that has a long history of dealing with earthquakes and the deadly waves that they spawn, Japan has never stopped working to improve its disaster mitigation systems. Even the current warning method has been criticized as too slow, given that many quakes occur less than 18 miles offshore, creating waves that take only five minutes to hit land.
By the time local authorities sound the alarm under the current system, more than 10 minutes has sometimes passed from the initial quake - and every second is crucial when a wall of water is moving at the speed of a jet airliner. A government study in 2003 showed that a tsunami resulting from an 8.6 magnitude quake in the Pacific south of Japan could kill up to 8,600 if evacuations were slow, spurring efforts to improve warning systems.
The Japan Agency for Marine-Earth Science and Technology has since developed a method to accurately predict the height of a tsunami three seconds after an earthquake hits. Current systems measure the correlation between different types of seismic waves that earthquakes produce - the initial P-waves and the slower S-waves. "But we can now estimate earthquakes using Global Positioning System (GPS) precision clocks and a method that measures only the first stage of the first P-wave," says Tsuji.
The new technology uses an existing system of quake-monitoring cables on the seabed to measure changes in water pressure immediately after a quake occurs with a pressure gauge attached to the cable. This system currently covers an area in the Pacific directly south of Japan, long thought to be the area where most tsunamis near Japan originated.
The Japan Meteorological Agency was allocated funding this year to extend the tsunami warning system to an area including the Pacific coasts of the Philippines and farther south toward Indonesia and Papua New Guinea. The project is set to begin in March, 2005.
Another system, recently developed by Hitachi Ltd. and the Earthquake Research Institute at the University of Tokyo, uses GPS technology to detect tsunami several kilometers offshore by measuring how much a giant 13-meter buoy rises or falls on the ocean surface.
• Sanae Benisty in Tokyo contributed to this story.