Is Asia Prepared for the Next Tsunami?

Is Asia Prepared for the Next Tsunami?

New research suggests how countries can save more lives the next time around.

By Julian Hunt in the Wall Street Journal

The Boxing Day tsunami of 2004 was the largest to hit the Indian Ocean in several hundred years, triggered by the fourth-strongest earthquake the world had seen since 1900. The amount of energy released is estimated to have been equivalent to the explosion of 475,000 kilotons of TNT, or 23,000 Hiroshima-sized nuclear bombs.

Some 228,000 people died, making it the deadliest tsunami in recorded history. In Indonesia’s Aceh region alone, hundreds of thousands of homes were flattened, some 800 kilometers of coastline destroyed and approximately 3,000 hectares of land washed away.

A decade on, our understanding of how to reduce tsunami risks has advanced. Yet to curtail the number of fatalities caused by future disasters, there are several lessons still to take to heart.

First is the value of holistic geophysical forecasting in predicting future tsunamis. This form of research makes use of the fact that tsunami-related disturbances are so large and so powerful that they disturb the solid earth, the oceans and the atmosphere. This does not just lead to mechanical forces and release of heat, as in storms, but also affects electrical, magnetic and molecular processes, especially higher up in the atmosphere.

Modern instruments have become so sensitive that they can measure magnetic fields one-millionth of the strength of the earth’s magnetic field, so tremors in the lithosphere can be detected long before large earthquakes and tsunamis occur. Russian research at the Geoelectromagentic Research Centre in Moscow confirms that the motions in tsunami waves, once initiated, can be detected over hundreds of kilometers from distant measurements of weak, slowly changing magnetic fields.

Second, since 2004, there has been progress in most aspects of warning systems, from ground-based technologies (such as seismic and electromagnetic recordings) to airborne ones (such as satellite detection of sea-surface disturbances). One reason the 2004 tsunami proved so devastating was that warning systems in the region were virtually nonexistent.

Yet even with better warning systems in place, some communities close to epicenters may not receive relevant information in time. This is why 80% of tsunami casualties tend to occur before any official warning actually arrives.

However, for more distant communities—including the Kenyan fishing community where the December 2004 tsunami arrived six hours after its initiation off Sumatra—warnings can be communicated very effectively. These warnings, which came through community groups, mobile phones and television, saved many lives.

Thus, research suggests that distributing data quickly, openly and locally is essential to saving lives. And it is mobile phones that are proving perhaps most effective, with special applications now developed for disasters. Conversely, where mobile phones are not in widespread use, as in Burma during a typhoon in 2008, warnings do not reach isolated communities, even when predicted well in advance.

As part of this warning process, more attention is needed to promote better understanding of the two key types of tsunami waves. Currently many tsunami public warnings, in the form of diagrams and pictures, only warn of large waves approaching land. This can be misleading given that the second type is preceded by a drop in the sea level and the retreat of the shoreline, all before a significant wave returns up the beach. This second type was what occurred in December 2004 and also in Japan in 2011. While the science of these two types of waves is now better understood than it was 10 years ago, it needs to be better reflected in warnings to the public.

Third, stronger infrastructure and community planning are needed, no matter the warning systems in place. Japan’s March 2011 earthquake and tsunami illustrated this point, especially highlighting the danger posed to nuclear facilities. The March 2015 meeting of the United Nations Office for Disaster Risk Reduction will take place in Sendai, Japan.

Several research institutions, including Delft University of Technology in the Netherlands, are trying to explain why in 2004 the sea retreated before roaring up the beach, drowning thousands of people. These events have been reproduced in a specially constructed lab at Arizona State University, where simulated tsunami waves yielding reliable estimates of future conditions can help coastal communities build more reliable structures.

The ability of officials and researchers to forecast tsunamis is increasing, but it is a constant race against time. We must therefore continue to prioritize research and development into ever-more resilient construction and design of infrastructure, from nuclear facilities to coastal fishing communities.

Lord Hunt is a visiting professor at Delft University and former director-general of the United Kingdom Meteorological Office.