January 2, 2005
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January 2, 2005
The Future of Calamity
By ANDREW C. REVKIN
N seven hours last week, great ocean waves scoured shores from Thailand to Somalia, exacting a terrible price in wealth and human lives. But unimaginable as it may seem, future catastrophes may be far grimmer. Many more such disasters - from earthquakes and volcanic eruptions, to floods, mudslides and droughts - are likely to devastate countries already hard hit by poverty and political turmoil.
The world has already seen a sharp increase in such "natural" disasters - from about 100 per year in the early 1960's to as many as 500 per year by the early 2000's, said Daniel Sarewitz, a professor of science and society at Arizona State University. But it is not that earthquakes and tsunamis and other such calamities have become stronger or more frequent. What has changed is where people live and how they live there, say many experts who study the physics of such events or the human responses to their aftermath.
As new technology allows, or as poverty demands, rich and poor alike have pushed into soggy floodplains or drought-ridden deserts, built on impossibly steep slopes, and created vast, fragile cities along fault lines that tremble with alarming frequency.
In that sense, catastrophes are as much the result of human choices as they are of geology or hydrology. Dr. Kerry Sieh, a veteran seismologist at the California Institute of Technology, has spent years studying some of the world's wealthiest and poorest earthquake-prone territory - not only the sickle-shaped scar of faults off Sumatra's west coast that caused last week's tsunami, but also California's San Andreas fault, which could, with a sudden twitch, submerge the inhabitants of some of the most valuable land on Earth.
The difference between the rich and poor countries, Dr. Sieh said, was that the rich ones had improved their building techniques and their political systems to deal with inevitable disasters.
In the Pacific Northwest, where offshore faults could generate a tsunami as large as last week's ocean-spanning waves, officials have created "inundation maps" to know more precisely what would happen in a flood and prepare accordingly. And in response to the threat of earthquakes, buildings on the West Coast now are designed to sway over shifting foundations, and new highway overpasses are no longer stacked like the jaws of a huge horizontal vise.
Istanbul, Tehran, New Delhi and other increasingly dense and shabbily constructed cities, on the other hand, are rubble in waiting. When an earthquake leveled the ancient Iranian city of Bam in 2003, for instance, more than 26,000 people were essentially crushed by their own homes. Several earthquake experts refer to the "seismic gap" as a way of describing this difference between the ability of rich cities and poor ones to withstand earthquake damage.
"Tehran is a city the size of Los Angeles, with thrust faults like Los Angeles," Dr. Sieh said. "In Los Angeles the next 7.5 quake might kill 50,000 people. In Tehran, that would kill more than a million people."
Nonetheless, elected officials and disaster agencies, both public and private, remain focused on responding to catastrophes instead of trying to make societies more resilient in the first place, said Dr. Brian E. Tucker, a geophysicist and the head of GeoHazards International, a private research group trying to reduce poor countries' vulnerability to earthquakes. For instance, while the United Nations in 1989 declared the 1990's the "International Decade for Natural Disaster Reduction," and created a secretariat to run it, it set no concrete goals or timetable for accomplishing them, Dr. Tucker said.
He described a recent study by Tearfund, a Christian relief agency, that found that less than 10 percent of the money spent on disaster relief by government agencies and institutions like the World Bank goes to preventive measures. According to the study, Mozambique, anticipating major flooding in 2002, asked for $2.7 million to make basic emergency preparations. It received only half that amount from international donor organizations. After the flood, those same organizations ended up committing $550 million in emergency assistance, rehabilitation and reconstruction financing.
Dr. Sieh said he was not confident that wealthy countries would ever recognize the value of prevention. Even as they grow more scientifically prescient, people have a blind spot for certain inevitable disasters, either because they play out over long time frames, like global warming, or because they are rare, like tsunamis.
"I really am wondering if, from an evolutionary biological perspective, we're really equipped to deal with things that only recur once every several lifetimes or longer," Dr. Sieh said.
Jeffrey Sachs, director of Columbia University's Earth Institute, was more optimistic, if only slightly so. He noted how Bangladesh had seen its mortality rates from flooding drop sharply since the 1970's, mainly by adopting simple means of getting people to higher ground, some as basic as installing high platforms for people to climb above the floodwaters.
But he also noted another class of cataclysms that which receive no blanket news coverage: malaria, AIDS, crop failures - even global warming.
"We're at a period in Earth's history where we're living on an edge where things can go terribly wrong if we're not attentive," Dr. Sachs said. "But we also have magnificent knowledge and technologies that could make the outcomes far better than they are now."
The tsunami assault, he said, could be a call to action. But he and Dr. Sieh agreed that it could also end up just another in a series of distant disasters, a disturbing distraction for the world's more fortunate nations.
"There is a technological and scientific basis for proactive strategies," Dr. Sachs said. "But they are not being applied, and there is no reason for that. It's not even a question of money. It's much cheaper to anticipate rather than respond." That is true, he said, whether the goal is restoring fertility to African soil or building a system to warn of tsunamis.
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Posted on Sun, Jan. 02, 2005
Look closely at ancient Earth to save lives now
Scientists, like art teachers who have not mastered anatomy, often assume that what they do not know is not important. And, when it comes to earth science, what they do not know is the pattern of geologic time, particularly what has happened beneath the ground in the billions of years the Earth has existed. What have been the consequences of large waves and water movement to whatever life existed on its surface?
Humans might know that the universe is theorized to be 15 billion years old, but the way we feel about ourselves in relation to a 4.5 billion-year-old Earth is not much different from the way indigenous people studying a night sky might have felt 10,000 years ago. The subject of what can possibly happen on Earth is simply too big for most of us to handle if we are to continue to be an optimistic race.
Yet there are facts that we should not let pass into an obscure scientific history, for remembering them will undoubtedly help ensure a safer future for all on our planet. This is harder than it sounds.
We have a tsunami warning system in the Pacific Ocean because, in recent history, we've experienced tsunamis there. We don't have a similar system in the Indian Ocean. This has something to do with the technologies developing nations can afford, of course. But it also has to do with the fact that our experience with the giant waves in this region is less immediate. Yet the single worst explosion in our known geologic history -- an eruption of a 20-by-60-mile caldera some 71,000 years ago -- occurred on Sumatra, just 100 miles from the epicenter of Sunday's earthquake.
The earlier eruption so filled the sky with ash that it probably created our last ice age.
And think of this. Earthquakes as a rule occur at the ridge of land and water, where plates usually meet and either slide, thrust or pull apart, releasing awesome power. But there are exceptions.
The largest earthquake ever in the United States that we know of, probably at least as large as the one that destroyed most of San Francisco in 1906, occurred in the Mississippi Valley area in 1811. Boats were thrown over in the river and people drowned. This earthquake, and its aftershocks, were so destructive that Congress passed the first federal relief act in 1815 to support the farmers whose land was turned to swamp, sand and mud.
But the seismological activity that caused that quake has never been explained in definitive terms. Scientists speculate that the Earth tried but failed to separate 600 million years ago, creating a weakness of some kind beneath the ground. The U.S. Geological Survey vaguely refers to the area as a plate boundary zone, which means that the agency doesn't know if there are plate boundaries in the vicinity. But we do have historical evidence of many substantial earthquakes in a wide area of the southern Midwest, from St. Louis to Memphis -- an area where more than 10 million people live today.
The greatest cliche in geology is the question, can it happen again? Sure. Will it happen again? Well, nature is never overdue, and we simply don't know.
It is mind-boggling to think that only 200 million years ago the Earth was one gigantic continent, and one can only imagine the explosions that broke it into today's continents.
And the truth is that there are physical realities in our world that we are not paying attention to. For instance, in 1971 an earthquake of 6.4 magnitude occurred in the San Fernando Valley. It occurred on a fault that had not been known to exist.
At one end of this valley is the Van Norman Dam, which lost 30 feet from its top, and tons of water, during the shaking. Behind it is a reservoir larger than the one that created the famous Johnstown, Pa., flood that killed 2,200 people in 1889. Afterward, engineers concluded that the Van Norman Dam would have collapsed had the quake lasted eight more seconds. Today, almost half a million people live in the valley.
The possibility of great landmasses falling into the ocean is also always with us, and recently scientists found vertical fault lines through a volcano on La Palma, one of the Canary Islands. The volcano has a crater about five miles wide and a half-mile high, and erupts about every 200 years. The last eruption was in 1948, but the newly discovered fault lines have convinced some scientists that eventually the huge crater will break apart and slide into the ocean.
Since tsunamis are created in proportion to the amount of land that has fallen into the water, this event would most likely create a wave mass never before known to written history, many times bigger than the 1958 wave at Lituya Bay, Alaska, produced when an earthquake cased a landslide into the sea. That 1,720-feet-high tsunami could have swept over the Empire State Building. Fortunately, it headed into a wildlife area rather than to Hawaii and Japan.
A wave from La Palma, if it hit the Atlantic seaboard, could be higher than the skyscrapers of Boston, New York and Miami. Scientists do not know if it will take one, four, or 10 eruptions to separate the landmass, only that the separation is inevitable.
The only good news is that volcanoes usually send signals before they erupt, and it would take eight hours for the wave to travel from Africa to the United States' eastern shoreline. It is not sufficient time, however, to move all the people who would be in its path. In any event, surely the mountain on La Palma should be reduced in size, to lessen the impact should it ever slide into the Atlantic. But, who will pay for such a huge reduction of a landmass?
Big earthquakes occur infrequently, but when they do they usually come unexpectedly and with horrendous power. It is, of course, dangerous to live in an earthquake-prone area, but what area in the world can we say is earthquake-safe? Surely the people in the Mississippi Valley feel they are safe, as do the people in New York City. Yet, New York has a fault line going across 125th Street that I guess 99 percent of the population doesn't know about.
And what if they did? Americans have always lived in dangerous places -- on the flat cyclone fields of the Midwest and on the hurricane-battered coasts of Florida.
I hope for the future in the same way I hope when I step onto an airplane. I hope the people in control know what they are doing.
But I also know that we will continue to be unprepared for disaster if we don't look more deeply into the past. I don't mean studying a volcanic eruption a century ago. I mean another past, in geologic time, that we simply don't know enough about.
Thinking about that explosion on Sumatra 71,000 years ago is a good place to start.
DENNIS SMITH, a retired New York City firefighter, is the author of the forthcoming ``San Francisco Is Burning,'' a history of the 1906 earthquake. He wrote this article for the New York Times.
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