It is extraordinarily difficult to get across to someone who has never experienced it the sheer, mind-numbing terror of being caught in a major earthquake. Even in California, where the population is constantly bombarded with information about what to do in the event of a quake, coherent, sensible thought ceases when the ground starts to tremble. Following the Loma Prieta quake that struck northern California in 1989, a survey by the United States Geological Survey revealed that only 13 per cent of the population of Santa Cruz sought immediate protection, while close to 70 per cent either froze or ran outside. This is aperennial problem with earthquakes; however well educated the people, when the ground starts bucking like a bronco and the furniture starts to hurl itself across the room, blind instinct takes over and tells them to 'get the hell out of there'. Unfortunately, this serves only to increase the death toll as terrified homeowners rushing screaming into the street provide easy targets for falling masonry and other debris crashing down from above. What they should be doing is diving beneath the nearest piece of heavy furniture or sheltering beneath the lintel of a convenient doorway.
Earthquakes are immensely destructive, mainly because most cities in regions of high seismic risk are dominated by buildings that are simply not built well enough to withstand the severe ground shaking of a major quake. Modern construction methods in California follow stringent building codes that ensure they can withstand earthquakes that would be devastating elsewhere, and this policy has borne considerable fruit by dramatically limiting death, injury, and damage during major quakes in the last 15 years. Even so, the North-ridge earthquake that struck southern California in 1994 is credited with losses totalling 35 billion US$, largely accruing from damage to older structures. Other earthquake-prone countries also have in place building codes designed to minimize damage due to ground shaking, but often these codes are simply not enforced. The terrible legacy of such a lack of commitment by government and local authorities became all too apparent when a magnitude 7.4 quake struck the Izmit region of Turkey in 1999, obliterating 150,000 buildings and taking over 17,000 lives. Many apartment blocks simply pancaked; successive floors collapsing to form a pile of concrete slabs beneath which opportunities for survival were minimal. More recently, in January 2001, a severe earthquake shook the Bhuj region of Gujarat state in northwestern India, flattening 400,000 homes and killing perhaps 100,000 people. Many of the deaths resulted from the traditional construction methods used in the region, which involved the building of homeswith enormously thick walls made of great boulders held together loosely with mud or cement, beneath heavy stone roofs. When the ground started to shake these buildings offered little resistance, collapsing readily to crush those inside.
During the last millennium, earthquakes were responsible for the deaths of at least 8 million people. Terrifying as this sounds, the rapid growth of megacities in regions of high seismic risk is set to ensure that this figure is surpassed, maybe in just the next few centuries, and some seismologists are already warning of the potential, in the near future, for a single large quake to take 3 million lives. If the unfortunate target were Karachi or Mexico City then, although the catastrophe would have appalling consequences for the host countries, the global impact would be minimal and would barely impinge upon the lives of most of the world's population. On the other hand, if ground zero were to be the Japanese capital, Tokyo, then the story would be very different. Projections to 2015 suggest that by this time the TokyoYokohama conurbation will be the greatest urban concentration on the planet, with a population a shade under 2 9
million. The city is located in one of the most quake-prone parts of the planet, where the Pacific and Philippine plates to the east plunge beneath the giant Eurasian plate, and was obliterated by a massive earthquake less than 80 years ago. While things have been ominously quiet since, it can't be long now before another huge quake devastates one of the world's great industrial powerhouses. When it does, the economic shock waves will hurtle out across the planet, bringing country after country to its knees. In order to provide an impression of the fate awaiting the Japanese capital, let me take you on a trip back to one of the great disasters of the twentieth century, the terrible event the Japanese call the Great Kanto Earthquake.
September ist, 1923, dawned like any other day for the inhabitants of Tokyo and Yokohama, but for many it would be their last. The quake struck just before noon, when the cafés and beer halls were packed with hungry workers and as families sat down at home to their midday meal. A low, deep rumbling grew rapidly to a monstrous roar as a fault below Sagami Bay ripped itself apart and sent shock waves tearing northwards towards the twin cities, crashing first into Yokohama and then — a bare 40 seconds later — into the heart of the capital itself. The quake registered a massive 8.3 on the Richter Scale, and so severe was the ground shaking that it was impossible even to stand. Within seconds, thousands of buildings, many with the traditional wooden walls and heavy tiled roofs, collapsed into heaps of rubble, bringing sudden oblivion to those inside. The great cacophony of grinding rock and falling buildings eventually gave way to the quieter
39 The Japanese capital sits in a region of complex geology where three of the planet's great tectonic plates meet but equally terrifying crackling of flames as fires started by thousands of overturned stoves began to devour the wood out of which many of the buildings were constructed. Whipped up by a brisk wind, a million small fires swiftly merged to form unstoppable walls of flame that marched across the ruins. Shocked men, women, and children cowered before them in open spaces, but to no avail. The firestorms roasted them alive. In one area of waste ground were immolated by the conflagration, so packed together that their charcoaled bodies were found still upright. The fires continued to consume what remained of the cities for two days and nights, before finally burning themselves out to reveal a post-apocalyptic scene of utter devastation. The true total will never be known but up to people may have lost their lives in the quake itself and the fires that followed. The cost to theJapanese economy was phenomenal — around 50 billion US$ at today's prices— and a combination of the quake and the Great Depression six years later led to economic collapse and severe hardship. Some have even suggested that these circumstances, as in the German Weimar Republic, helped stoke the fires of nationalism and the rise of the military, leading to conquest, imperialism, and ultimately war.
In the early years of the new millennium, the twin cities of Tokyo and Yokohama again await their fate, only this time it will be far, far worse, both for Japan and the rest of the world. Now the industrial and commercial might of the region constitutes one of the major hubs of the world market, with spokes reaching out to the far corners of the Earth, helping
to bind together a global economic machine upon which the wealth of all nations now depends. When Tokyo falls, so will Japan, and the rest will follow — but when? Strains have now been accumulating in the rock beneath and around the capital for 78 years and, apart from a relatively small— magnitude 5.9 — quake in 1992, the region has been seismic-ally silent. Both the government and the population know, however, that this can't last and money is being poured into constructing earthquake—proof buildings, improving educa— tion and emergency planning, and even trying to predict the precise timing of the next 'big one'. So far, however, the accurate prediction of earthquakes has proved to be out of reach, and prospects for a breakthrough in the near future are slim. Furthermore, a substantial proportion of the older building stock remains vulnerable, and an estimated one mil— lion wooden buildings continue to provide an excellent potential source of fuel for the post—quake fires. Just seven years ago, 6,000 people died in the Kobe earthquake, 400 kilometres south of Tokyo, which can be viewed perhaps as a mini version of the catastrophe awaiting the capital. At Kobe serious fire damage contributed significantly to the overall destruction and to the huge economic losses of zoo billion US$, and it was clear that emergency preparedness and response were far from effective, and certainly well below the rest of the world's expectations, given the general perception of Japanese society as a model of efficiency. For one reason or another, the authorities were simply unable to cope with the chaotic aftermath of the event. Planswere not in place to ensure transport of emergency supplies and equipment to where they were needed, once roads were blocked by debris and railways out of commission, and many of the city's hundreds of thousands of homeless received little or no help for several days after the quake. It is fair to say that some at least of the problems encountered at Kobe reflect the hierarchical structure of Japanese society, which stifles independent decision making and action and hinders rapid response in emergency situations. Without significant changes it is difficult to see how any earthquake emergency plan for the Tokyo region could function effectively within the strait-jacket imposed by such a deeply ingrained and restrictive social etiquette.
The geological setting of Tokyo andYokohamais complex, with three of the Earth's great tectonic plates converging here. The enormous strains associated with the relative movements of these plates are periodically relieved by sudden displacements along local faults, which in turn lead to destructive earthquakes. In fact, there are so many active faults in the vicinity that the region is at risk from major quakes occurring at four different locations, all of which are thought by seismologists to be overdue or at least imminent. Some 75 kilometres south of Tokyo and Yokohama, close to the city of Odawara, seismologists expect a magnitude 6.57 quake to strike at any moment. Although causing serious damage locally, and moderate damage in the twin cities, this isunlikely to hit the capitalwith the force of the 1923 quake. Similarly, another so-called Tokai earthquake is imminent beneath Suruga Bay, 150 kilometres to the southwest. Scientists forecast that this will be a huge, magnitude 8 event that will undoubtedly batter the coastal city of Shozuoka, but will probably again be too far from the capital to have a serious impact. Far more worrying are two other expected quakes that pose a much greater threat to the Tokyo region, and which are awaited with much trepidation. Scientists predict that a quake as large as magnitude 7 could strike at any time — directly beneath the capital. This event, known locally as a chokka-gata quake, will cause severe damage in the cap— ital, although Yokohama is likely to be less badly hit. Worst of all, a repeat of the 1923 Great Kanto Earthquake itself is only thought to be a few decades away. This is likely to take the form of a massive magnitude 8 event resulting from the tear— ing open of a fault beneath Sagami Bay to the south. As was the case almost 80 years ago, the shock waves will race north— wards, rolling first into Yokohama and barely half a minute later into Tokyo itself.
The national government still maintains that its scientists will detect in advance the warning signs that the 'big one' is on its way. Such faith in science is both rare and touching but in this case entirely misplaced. Retrospectively, it has been noted that some earthquakes have been preceded by falls in the water levels in wells and boreholes, and in elevated con— centrations of radioactive radon gas issuing from the rock, but this is not always observed. Furthermore, such changes can occur without a following quake, making them notori— ously unreliable for prediction purposes. A group of Greek scientists claim that they can detect electrical signals in the crust prior to an earthquake, but there is no convincing evidence for this and the method is derided by most seismologists. On the other hand, there does appear to be something in the idea that animals, birds, and fish behave strangely before a quake, and the Japanese are actually undertaking serious research to find out if catfish — amongst other organisms — can help them forecast the next big one. The problem here is that no one knows how animals can detect a quake before it happens, although it has been sug— gested that strain in the rocks generates electrical charges in fur and feathers, and perhaps even scales, that trigger small electric shocks, making the animals understandably restless and irritable. But this begs the question, how do you decide whether, for example, a pig is behaving strangely?
In the absence of an alert from a precognizant catfish, it is likely then, that the next great quake will strike the Tokyo region with no warning whatsoever. Recently constructed buildings will fare reasonably well, but many older properties will crumble. Notwithstanding an automatic gas shut—off device that is fitted to some buildings, exploding fuel tanks, fractured gas mains, and oil and chemical spills will ensure no shortage of fires to feed on a million wooden buildings. As in 1923, huge conflagrations are expected to cause at least as much destruction as the quake itself, and to inflate the death toll hugely, which some suggest could easily top the 200,000 of the Great Kanto quake. While it is difficult to estimate in advance the economic losses resulting from the next big one, a modelling company that services the insurance industry has come up with the extraordinary figure of 7 trillion US$. This would make the cost of the next Tokyo quake 35 times greater than Kobe, so far the most expensive natural disaster ever, and 200 times more than California's 1994 Northridge quake — the costliest natural catastrophe in US history.
The impact on the Japanese economy is widely expected to be shattering.Japan is enormously centralized, and the Tokyo region hosts not only the national government but also the stock market and 70 per cent of the headquarters of the country's—and the world's — largest companies. Currently, the GDP of the region is comparable to that of the entire UK, and despite its current economic woes, it is likely that this will be substantially larger when the big one eventually strikes. In order to rebuild and regenerate it is highly likely that the Japanese will have to disinvest from abroad on a massive scale, dumping government bonds in Europe and the States, selling foreign assets, and shutting down overseas factories. It is well within the realms of possibility that as country after country finds itself fighting to cope with the swift unravelling of the global economy, a recession deeper than anything since the 1920s would soon set in. Neither would it be any great surprise to find unemployment reaching staggering proportions and the political and social fabric of many states starting to pull apart. No one knows how long a post—Tokyo quake depression would last—it could be years or even decades—nor just how bad it would be. Equally importantly, how long do we have to wait until such a speculative scenario is played out for real? The frightening consensus amongst seismologists is 3 0 years—at best.
Despite occasionally being depicted in the media as 'Disas-terman', I would hate you to regard me purely as a harbinger of doom, and close the book at this point with a feeling of hopelessness about the future. Yes, the Earth is geologically very dangerous, and the more geologists study our planet the more potentially serious the tectonic threat to the survival of our civilization appears to be. On the other hand, we are learning all the time; collecting data that can be utilized to counter or at least mitigate the impact of the next supereruption or gigantic tsunamis. Eventually, it probably will be possible to predict earthquakes with some accuracy and precision, and certainly within a century it is likely that nowhere on the planet will a volcanic island become unstable or a huge new batch of magma swell the surface without our satellites spotting them well in advance of catastrophe. On an almost daily basis Earth scientists are tackling some of the greatest threats to our society and incrementally they are getting to grips with them. At the very least, the next time our planet shudders on a grand scale we will be far better prepared than our distant ancestors, who faced the might of Toba with incomprehension and sheer terror.
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