Disaster early warningTen years after the Boxing Day tsunami, are coasts any safer?
Ten years ago we witnessed one of the worst natural disasters in history, when a huge earthquake off the coast of Sumatra triggered a devastating tsunami which swept across the Indian Ocean. An estimated 230,000 people lost their lives, and 1.6 million people lost their homes or livelihoods. The impact was greatest in northern Sumatra because of its proximity to the earthquake. Catastrophic shaking was followed within minutes by the full force of the tsunami. Thousands of people were also killed in distant countries, where the earthquake could not be felt. If they had received a warning of the approaching tsunami, they could have moved inland, uphill or out to sea, and survived. Future tsunami disasters are inevitable, but with better technology, education and governance we can realistically hope that a loss of life on the scale of the 2004 tsunami disaster will not happen again.
Ten years ago we witnessed one of the worst natural disasters in history, when a huge earthquake off the coast of Sumatra triggered a devastating tsunami which swept across the Indian Ocean.
An estimated 230,000 people lost their lives, and 1.6 million people lost their homes or livelihoods.
The impact was greatest in northern Sumatra because of its proximity to the earthquake. Catastrophic shaking was followed within minutes by the full force of the tsunami.
Avoidable deaths
Thousands of people were also killed in distant countries, where the earthquake could not be felt. If they had received a warning of the approaching tsunami, they could have moved inland, uphill or out to sea, and survived. Tsunami take several hours to cross an ocean, becoming much larger and slower as they reach the coast.
Back in 2004 there were long-established tsunami warning systems in the Pacific Ocean, which has many subduction zones— places where two tectonic plates collide — capable of generating huge earthquakes or volcanic eruptions.
Other regions, including the Indian Ocean, did not have a warning system. The probability of a major tsunami was judged to be too low to justify the cost, especially for poorer countries.
The Boxing Day 2004 disaster changed all that.
Progress in the past decade
In early 2005, the UN agreed to develop an international warning systemincluding regional systems in the Indian Ocean, North East Atlantic & Mediterranean, and Caribbean. The Indian Ocean tsunami warning systemwas developed between 2006 and 2013, at a total cost of at least $19 million.
In the three years prior to October 2014, bulletins were issued about twenty-three Indian Ocean earthquakes, resulting in a small number of potentially life-saving coastal evacuations. Most of these twenty-three earthquakes did not actually generate a threatening tsunami because they did not cause significant uplift or subsidence of the seafloor. But false alarms can provide reassurance that communications work well, or highlight weaknesses.
Communications and evacuation procedures are also regularly tested by international mock drills, often based on worst case scenarios.
