The week of November 29, 2015

The story behind the Indian Ocean tsunami warning system

By Nithin Coca

It took nearly three hours for the 2004 Indian Ocean tsunami, the deadliest natural disaster in human history, to travel from its epicenter near Sumatra, Indonesia, to the eastern coasts of India and Sri Lanka. By then, it had already devastated Phuket, Thailand; Banda Aceh, Indonesia; and India’s Andaman and Nicobar Islands—and was making international headlines.

It was 2004, well into the era of the Internet, mass communication, cellphones, and social networking, but for fishermen and villagers in southern India and Sri Lanka, it might as well have been 1904. Though warnings were sent to the Indian coast guard, there were no protocols for getting that lifesaving information to villages far from urban centers.

The tsunami hit with virtually no warning, killing more than 47,000 people in just those two countries. Across the Indian Ocean, the final estimated death toll was more than 220,000, nearly all of whom received absolutely no advance notice.

In the wake of the tragedy came a new drive for a tsunami warning system. Previously, tsunamis were rarely, if ever, seen as a threat in the region; in the Indian Ocean the geologic record shows occurrences have been highly variable, with the intervals between tsunamis ranging from just every few decades to, in this case, around 500 years. (Japan, by contrast, sees tsunamis regularly, and its sophisticated warning system likely saved thousands of lives in 2011.) But the massive death toll changed everything, especially when readers safe in the United States learned about the disaster long before those in the wave’s path in Sri Lanka.

The push for an effective, transnational, digitally connected warning system began in earnest, but it wouldn’t be an easy project. The region includes several of the world’s most populous countries, with hundreds of millions living along the coast, but their people are mostly poor. India, 1 billion strong, has a per capita GDP of only $1,600, while Indonesia’s GDP, with 240 million inhabitants, is only marginally higher at $3,490. Many high-risk countries—the Maldives, Bangladesh, and Sri Lanka, for example—simply didn’t have the resources to build or maintain their own warning system.

The massive death toll changed everything.

Moreover, in the immediate aftermath, those countries were focused on reconstruction. Funding for any warning system would have to come from international donors, who had pledged billions in relief aid. Germany led with a €60 million investment (roughly $64 million U.S.), with Japan also playing a key role. Australia, meanwhile, invested in its own warning center that would work with regional infrastructure.

“I’ve done international work for 30 years now,” said Dr. Ray Canterford, deputy director of hazards, warnings, and forecasts at the Australian Bureau of Meteorology, who played a key role in setting up the Australian Tsunami Warning System. “After the tragedy, I had never seen the level of international cooperation that occurred. Everyone shared their information, gave freely of their advice, in actually building a system.”

The goal: learn from the failures of 2004 in building a robust, integrated warning system for the entire Indian Ocean. After years of work by global scientists, development agencies, and governments, in 2013 the Indian Ocean Tsunami Warning System (IOTWS) became fully operational. It can quickly detect earthquakes, discern whether or not they will produce a tsunami, monitor how ocean waves are propagating, and predict where they might go. This detection and monitoring network then provides information to the region’s three tsunami warning centers, run by Australia, Indonesia, and India.

Though the system is now operational, its success wasn’t a sure bet. It faced several challenges, chief of which was sustainability and maintenance. Using the same expensive equipment as the Pacific Ocean warning system (which receives reliable funding from the United States and Japan) would put an onerous cost burden on countries that, once international funding dried up, may balk at the price tag.

The initial focus was on using technology that would provide reliable data but at a far lower cost. For example, until the early 2000s, ocean buoys were by far the best technology for detecting the often minute deep-sea pressure changes signaling a tsunami. They’re also incredibly difficult to maintain. They are expensive, highly susceptible to vandalism in crowded waters, and require regular maintenance and technical expertise to operate. So they were replaced with a GPS shield using freely available satellite data and computer models able to detect sea level variations from space, with only tiny loss of time and accuracy as compared to buoys. Data from the shield is analyzed using sophisticated computer models at warning centers.

“We have made quantum leaps in technology, in the running of computer models to measure the tsunamis going across the ocean, and in the ability to share data,” Canterford said. A comprehensive, open information-sharing network was a necessity for the project, as it meant providing important data to smaller, poorer countries (such as the Maldives or Sri Lanka) that previously would have only been available to, for example, Australia, which already has a sophisticated warning system.

“Data from these networks are available in near real time to the three regional JTWCs and [from there] to the National Tsunami Warning Centres of the 28 member states of the IOTWS,” said Tony Elliott, head of secretariat for the coordination group.

“We have made quantum leaps in technology, in the running of computer models to measure the tsunamis going across the ocean, and in the ability to share data.”

Also key was setting up effective communication protocols. A warning sent from Australia to India, thousands of miles away, would be useless if it then didn’t reach the actual people who needed to evacuate. The Intergovernmental Oceanographic Commission supported the development of technical, educational, and communication plans that are scientifically based and culturally adapted for each of the 28 member countries. This meant providing tsunami education, conducting evacuation drills in high-risk zones, and ensuring that communications systems—whether police radio, cellphones, or broadcast television—are properly set up to receive and send warnings.

“Information sharing is baked into the structure of the sector network,” said Andrew Schroeder, director of research and analysis at Direct Relief. “It is processed at the [JTWCs], and then that information goes out to everyone in the network.”

Today the system can, in most countries, automatically text warnings to phones in affected areas, alongside simultaneous television and radio warnings. “Once we receive the seismic information, within approximately 20 minutes, we can transit information across the Indian Ocean about tsunamis that may impact countries,” Canterford said. He and others hope that number will go down as the system becomes more dense, models become more accurate, and communication coordination improves.

It’s a great improvement over the state of affairs in 2004, when even a warning coming 20 minutes after the tsunami was detected would have given Sri Lankans and Indians more than two hours to flee. If such a system had existed then, the death toll in these two countries would have been far, far less. Perhaps, with functioning local infrastructure and a well-prepared populace, it could have been zero.

That would be a perfect outcome, of course. But any system will be imperfect, which makes it harder to judge effectiveness. “Defining success is very hard,” says Dr. Jörn Lauterjung, head of scientific infrastructure at GFZ German Research Centre for Geosciences, who led the German government’s involvement in the IOTWS. Even if, in 2004, 75 percent of the lives had been saved, that still would have meant a death toll over 50,000. And there are facts that simply cannot be overcome. In 2004, for example, a warning could have provided ample time for evacuations in India and Sri Lanka, but in parts of Indonesia near the earthquake epicenter, people would have had barely more than a few minutes’ warning even in the best-case scenario.

“The only thing is seeing how the system performs over time,” said Lauterjung. “We saw the physical limitations of the system in 2010 when we still had 400-plus victims.” That was when a magnitude 7.7 earthquake off the north coast of Sumatra triggered a deadly tsunami. The system worked as expected, but the quake struck only five to 10 minutes before the accompanying tsunami. Indonesia’s central warning center sent out alerts within five minutes, but with so little time, the warnings couldn’t reach the most remote islands. Still, without the IOWTS, the death toll would likely have been much worse.

“There was an instructive difference between then and 2004,” Schroeder said. “There was an information flow happening, and people did use it to get out of the way.”

New technology alone is not a complete solution. The warning system has to work with existing infrastructure and, in the end, human preparedness. “Making sure that there is a localized infrastructure, with plans, that is ready to go is key to being able to respond to a disaster,” said Schroeder, pointing to Mexico, where locally run evacuations were a key reason that Hurricane Patricia did not result in high death tolls. Ultimately, IOTWS can help to determine tsunami risk and the information can be spread far and wide, but without a strong local response infrastructure, all the warnings in the world won’t matter.

Today, though, the countries on the Indian Ocean susceptible to tsunamis are one big step closer to saving lives. When the next wave comes—and it will—they’ll be ready.

Illustration by J. Longo