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Posted in 2011

Japan and the Next Step for Disaster Preparedness

Modern technology saved thousands of lives Friday. Now we need to improve care for urban survivors.

This article by Julian Hunt and Simon Day appeared in the Wall Street Journal on Monday, March 14, 2011. Lord Hunt is visiting professor at Delft University of Technology and former director-general of the UK Met Office. Mr. Day is a researcher at the Aon Benfield Hazard Research Centre at University College London.

The 8.9 magnitude earthquake that struck Japan on Friday is the largest to hit the country in recorded history. It has numerous similarities, in both type and scale, to the 8.5 magnitude quake which struck Japan in 1896. Around 27,000 people are estimated to have been killed by that quake and the subsequent tsunami, which was some 25 meters high. In this case, the death toll could far exceed 1,000, most of those victims to the tsunami.

While that toll is tragically high, it is worth noting the scientific, technological and institutional developments that will have kept Friday’s earthquake and tsunami from claiming as many victims as previous disasters did. We now have a better understanding of the linkage between geophysical processes and detection technology, and have improved the education of, and communication to, at-risk communities.

All this is an undeniable mercy in allowing so many more people to survive such disasters than would have been possible before. But it also poses a new challenge for policy makers, one that came into focus over the weekend in Japan and that ought to be on the minds of disaster planners elsewhere: how best to care for hundreds of thousands, or even millions, of survivors who are dislocated by a severe natural disaster.

Japan shows how complex this question has become. Providing drinking water, food and shelter to those affected has become a major logistical challenge. Hundreds of thousands of Tokyo residents who live miles away from their houses and depend on modern urban transportation systems to get home each evening found themselves stuck in office buildings ill equipped to handle them.

This is a significant consequence of modern urbanization. The proportion of the world’s population living in urban areas is expected to reach between 60% and 70% later this century, from around 50% now. Japan is the epitome of this: Only 5% of the population works in agriculture (a proxy for rural residence), and around 80 million of Japan’s 127 million people are concentrated on the Pacific shore of Honshu island—the region that includes Tokyo.

Simultaneously, there is a movement toward very large cities with populations exceeding one million. In 1950, there were only 83 cities in the world of such a size, whereas this number had risen to 468 by 2007. There are now some 21 "mega cities" of greater than 10 million inhabitants—Tokyo is one of those.

The high concentration of people per square meter in urban areas, anywhere from 100 to 1,000 times the global average, can make populations more vulnerable to extreme natural hazards ranging from earthquakes to heat waves and floods. Even a localized disaster in a city can affect exponentially more people than a disaster hitting a similar land area in the countryside; the effect is magnified further for a region-wide disaster such as Friday’s earthquake.

The growing size of many urban areas also means that people sometimes cannot physically escape in the event of extreme hazards, as recent hurricanes and tsunamis in the United States and Indonesia have shown. Where attempts have been made to evacuate multi-million populations, lives have sometimes been lost in the transport systems as they seized up.

This means policy makers and architects face the question of how to provide refuge for those people during and after a disaster, and how those refuges should be integrated into the design of structures. The problem is much more difficult than simply building a bunker in the basement. Refuges have different roles for different types of disaster. For tsunamis, a shelter is usually only needed for a short period, as with high winds, tropical cyclones and landslides. For longer lasting disasters, such as volcanic eruptions, people have longer warning, and behave differently (for instance, bringing goods and even animals to the shelters in rural areas).

Regulators and engineers are only starting to grapple with this kind of question, but already some points are clear. Increasingly, communities in urban areas will have to understand and be prepared for risks of hazards and need to be involved in addressing them, in partnership with local and national government. This will involve training communities to deal with a range of potential natural disasters relevant to their local areas.

Structural engineers, planners and social scientists will also need to consider more urgently the design of appropriate shelters in urban and also in rural areas (for instance, parks and open areas may also act as refuges). This will require intensive study and resources to ensure good design and effectiveness. Careful study of unfolding events in Japan could help this effort over the long run.

The complexity of policies that are needed for dealing with these issues may be hard to envisage, and even harder to carry out. However, change is urgently needed and the longer we wait, the harder it will become to achieve and the more lives that will be lost.

Predicting earthquakes will come sooner than we think

This article by Kees Vuik and Mehfooz Rehman first appeared in The Australian on February 24, 2011.

Kees Vuik is a professor and Mehfooz ur Rehman is a PhD candidate at Delft University of Technology in The Netherlands.

THE 6.3 magnitude earthquake that hit Christchurch is a truly appalling tragedy and it is little wonder that New Zealand’s Prime Minister John Key has said that we may be witnessing his country’s darkest day.

The country is, of course, no stranger to earthquakes; it experiences more than 14,000 a year, of which only about 20 on average have a magnitude greater than 5.0. However, this week’s earthquake, NZ’s deadliest disaster in at least 80 years, has already caused an estimated $3 billion in damage and was so forceful it shook 30 million tonnes of ice from NZ’s biggest glacier.

While world attention is rightly focusing on the effort to save the lives of those trapped by fallen buildings, some media coverage has so far obscured the fact that the science of earthquake prediction is improving and holds much promise in the next few years. Although this will be of no solace for the people of Christchurch, what this means in practice is that in the not too distant future scientists might be able to provide warnings for at least some similar events, thus helping to minimise loss of life and wider devastation.

Predicting earthquakes was once thought to be impossible owing to the difficulty of calculating the motion of rocky mantle flows. However, thanks to an algorithm created by the Delft University of Technology, we now know that it is possible to model these underground streams.

Much of the early experimentation with the new algorithm has been based around the North Anatolian Fault. This is an active fault that runs along the tectonic boundary between the Eurasian Plate and the Anatolian Plate. It extends across northern Turkey and into the Aegean Sea. The last time there was a severe earthquake along this fault line, at Izmith in Turkey in 1999, 17,000 people were killed.

Our colleagues in Utrecht are applying our algorithm to create a model (consisting of 100 million underground grid points) of the North Anatolian Fault (essentially the underground in Greece and Turkey up to 1000km deep). What this information allows us to ascertain is where the underground stresses are strongest, an often telltale sign of the most dangerous potential earthquake trigger points.

As good as this model is, however, it still needs refinement. This is because the link between earthquakes and underground flows is complex and hard to compute. In practice, calculating such flows means constructing very complex mathematical systems made up of millions of pressure and velocity values at all of the underground grid points.

This has given rise to the need to scale up the solution time linearly, a feat that researchers had previously found too difficult. While this scaling up has been achieved, thus making the model more accurate and comprehensive, the project’s complexity has been increased considerably.

Nevertheless, after finishing our work on the North Anatolian Fault, Delft and Utrecht universities intend to try to model the tectonics of the entire earth, a truly ambitious project that will involve perhaps one billion grid points (what we call our fine grid).

To make the computations for these one billion points will require surmounting yet another big hurdle, the "parallel computing" problem.

That is, increasing the number of computers in a system generally means that they work less efficiently.

However, the Utrecht team has already been working with a test sample of 500 computers and we believe we have mitigated this problem with our algorithm.

Despite this breakthrough, computing the one billion parts of the fine grid is a long-term program and, to push forward in the meantime, we are also working on a technique called coarse grid acceleration.

Our coarse grid uses only a small number of sample points in all of the earth’s various strata, thus allowing us to obtain fast, accurate solutions for all of these sample points, leading to considerable savings in computer time.

Finally, we also plan to implement the algorithm on video cards that can speed up the computation by a factor of 100 or more.

While much more hard work and innovation lie ahead, this new frontier of seismology is therefore genuinely path-breaking and already achieving exciting results. However, as the Christchurch earthquake has painfully reminded us, true success will be achieved only when we reach the stage at which human lives are saved by applying our research in practice.

© 2011 TU Delft