1 March 2010Democracy Now!
Even as the people of southern Chile continue to grapple with the rising death toll and the devastation wrought by Saturday’s massive earthquake, many seismologists believe the wreckage could have been far worse. The 8.8-magnitude earthquake that struck Chile early Saturday morning was 500 times more powerful than the 7.0-magnitude earthquake that struck Haiti on January 12th of this year. But it caused only a fraction of the casualties in comparison to the 300,000 people estimated to have died in Haiti. Seismologists suggest that one reason for the difference in scale is that Chile enforced building codes for earthquake resistant structures after the experience of a 9.0-magnitude earthquake fifty years ago in 1960.
Roger Bilham, professor of geology at the University of Colorado. He is the co-author with Susan Elizabeth Hough of After the Earth Quakes: Elastic Rebound on an Urban Planet.
AMY GOODMAN: In Chile, rescue workers are searching for survivors under the rubble following Saturday’s massive 8.8 earthquake, one of the strongest in recorded history. More than 700 people were killed, with the number expected to rise. Chilean President Michelle Bachelet has announced emergency measures to deal with the destruction. She said one-and-a-half million people have been affected by the earthquake and declared a “state of catastrophe.” A curfew has been put in place in some areas. The quake heavily damaged many of the country’s roads, airports and ports. It also triggered a tsunami that killed at least four people and caused serious damage to at least one port town. Concepción, Chile’s second largest city, about 300 miles south of Santiago, one the hardest hit of the cities. The mayor has said food is running out and the situation is getting out of control. Thousands of people remain homeless. The army has been sent in to support local police. Security officials used tear gas and water cannons to disperse crowds who took food and supplies from a supermarket in Concepción. But according to the New York Times, law enforcement authorities, heeding the cries of residents that they lacked food and water, eventually settled on a system that allowed staples to be taken but not televisions and other electronic goods. Even as the people of southern Chile continue to grapple with the death toll and the devastation wrought by the massive earthquake, many seismologists believe the wreckage could have been far worse. The 8.8-magnitude earthquake that struck Chile early Saturday morning was 500 times more powerful than the 7.0-magnitude quake that struck Haiti on January 12th, but it caused only a fraction of the casualties in comparison with the 300,000 people estimated to have died in Haiti. Seismologists suggest one reason for the difference in scale is that Chile enforced building codes for earthquake-resistant structures after the experience of a 9.0-magnitude earthquake fifty years ago in 1960. Earthquake expert Roger Bilham argues it is quality of building construction and not simply the strength of the tremor that poses the most danger during an earthquake. He warns some of the fastest growing cities in the global south are also those facing significant seismic hazards, and the rapid pace of haphazard construction in these cities puts some 400 million people at risk. Bilham was among the first seismologists to visit Haiti after the earthquake and in a recent article in Nature magazine calls for the enforcement of earthquake-resistant construction guidelines. University of Colorado professor of geology and co-author with Susan Elizabeth Hough of After the Earth Quakes: Elastic Rebound on an Urban Planet, Roger Bilham joins me now from Denver, Colorado. We welcome you to Democracy Now! It’s very good to have you with us. ROGER BILHAM: Good Morning. AMY GOODMAN: Roger, can you start off by explaining the magnitude of the earthquake that has hit Chile and the scope of the damage? ROGER BILHAM: Yes, a magnitude-8.8 earthquake is one of the biggest that you can have on the planet. In fact, the very largest we know about also happened in Chile in 1960, as you rightly point out. It had a magnitude of 9.5, much bigger than the one that’s just occurred. However, the death toll in Chile during that earthquake was only 1,600 people. We may reach four figures in this earthquake, but we have to think of this as a tremendous success story. Earthquake-resistant construction prevails throughout Chile. They have an intelligent government that enforces these regulations. And they have constant reminders of what earthquakes can do. So, although a tremendous number of buildings have been damaged, the buildings are damaged to the point that people can walk out of them. In Haiti, this did not occur. The buildings were shaken violently and completely pancaked, in many cases, because there was no earthquake resistance at all. And although Haiti has a history of earthquakes, stretching back to the same period of time—Christopher Columbus obviously arrived 1492, we don’t know about earthquakes before then—although Haiti has this extraordinary long history of earthquakes, the local government was completely unaware of the potential effects of bad building practices. AMY GOODMAN: And when you talk about bad building practices, what exactly do you mean? What did Chile have that Haiti didn’t have? ROGER BILHAM: Well, first of all, there are various things that earthquake engineers insist on. The survival of certain critical structures, like hospitals, schools, fire stations and so on, those have to survive earthquakes intact and operate the next, you know, few minutes after the shaking has stopped. It turns out that some of these hospitals have been damaged, but probably not as many as could have. Now, what do you do to make a building safe from earthquakes? You need good quality foundations. Most buildings now going up are known as concrete skeleton designs. They have a structure of steel embedded in concrete. And you have to make sure you have the right kind of steel. If you use brittle steel, for example, the steel will simply snap during an earthquake. What you need is ductile steel. It costs a little bit more. In Haiti, it was all brittle steel, steel without ribbing, even, in terms of little corrugations that hold the concrete together when shaking commences. There are little structural members that look as though they’re in place simply to hold the steel in place during pouring of the cement, those things called stirrups. In fact, the stirrups used in Haiti were very weak, almost chicken wire-type strength, whereas in Chile, I’m sure, they applied the appropriate strength and thickness. And what these little pieces of metal do is stop the columns from exploding during the violent vertical shaking in an earthquake. Then the quality of the cement matters. If you mix three parts of sand to one part of concrete, which is something they’ll never tell you in school, but which most construction people know, you get good quality cement that doesn’t fall to pieces in an earthquake. However, if you go down the beach and shovel beach sand into a wheelbarrow and take it back to your building site without washing it or without checking, you know, exactly what it’s got in it—it might have dirt or soil, or it might have salt in—you finish up with a very weak cement. And it’s all too tempting, if you’re building your own house, as must have occurred frequently in Haiti, to take four parts of sand or five parts of sand, making an extremely weak cement. Another thing is the addition of aggregate. When you build strong buildings, as an earthquake engineer would certainly be doing in Chile, and have done, you use a very angular kind of aggregate. If you use rounded pebbles, the pebbles don’t grab on the cement, and they just fall to pieces. So there are a number of very obvious things that can be done, and unfortunately, people are not told how to do this. You know, very frequently, the lowest-paid workers turn up at a construction site, and they’re told to, you know, mix some cement, follow what that man is doing over there, and assemble it. Well, if there’s an engineer on board, it gets done right. If the man does it on his own, he may well be copying incorrect practices. And as a result, Haiti has duplicated a series of catastrophic designs that are weak from the foundations up and consequently fell down. AMY GOODMAN: Professor Bilham, are there an increased number of earthquakes? I mean, this weekend you have what happened in Chile. Also, wasn’t there a small one in Pakistan? And then, of course, you had the horror in Haiti on January 12th. If you could talk about these, and beyond, in China, in Pakistan, in the past, in the United States. ROGER BILHAM: Of course, yes. Earthquakes are happening all the time. They’ve been happening for the last several billion years on our planet, and there’s no change in their frequency. It looks like large earthquakes are happening suddenly now, a kind of conspiracy effect. No, it’s just a statistical fluctuation. We have to worry about earthquakes that actually occur near population centers. We don’t need to worry about earthquakes that happen in the middle of the ocean. Nobody is there, just a few fish. So, what really matters is where our populations are. And one of the most unexpected things is if you make a map of the world and plop down all the cities that you know about, the very largest of them, probably half of them, are located on plate boundaries. Plate boundaries is where earthquakes occur. Now, supposing you were coming in from a distant galaxy and you wanted to just populate the planet, you would try to avoid those places. But we have grown up on this planet, and we found that plate boundaries are in fact very desirable places to live. They’re on the seashore. There’s usually a good trading arrangement, even inland, near mountain belts, which are plate boundaries, like the Himalaya and parts of Iran, and so on. Cities are often located near sources of water, and these sources of water come out at range fronts. In other words, all the most desirable places on our planet appear to be populated by very, very large cities. Now, if you wind the clock back 150 years, you find that these were only villages. The population of the world has increased tenfold in the repeat time of most damaging earthquakes on our planet. And so, we have set up a disaster waiting to happen in probably a hundred cities with populations more than a million people. And one could list—one could list these hundred cities, and probably two or three of these will be damaged in the next two or three decades. A completely unacceptable prediction. It should not be possible for us to say that we’re going to lose another 500,000 people. Six hundred and fifty thousand people have died from earthquakes just since 2000. That’s up almost fourfold since the previous two decades. And you could ask, well, why is this? Well, it’s partly a statistical fluctuation in the locations of large earthquakes that are occurring, and it’s partly a recurrence of these big earthquakes to cities that were former villages only 200 years ago. We know their history of earthquakes, and we know they will have a future of earthquakes. And so, many of these cities, mostly in the developing nations, are slated for demolition by earthquakes. And it’s—a well-known phrase is that earthquakes don’t kill people, buildings do. And we are now seeing that buildings are in fact weapons of mass destruction. And in fact, it’s, to me, completely unacceptable that we should live in a world where you can shake the ground a little bit, and the building will fall down. It’s just nonsense. We know how to do it right. It’s just that we haven’t done it right. It will take a long while, maybe— AMY GOODMAN: How does that kind of building get enforced, Roger Bilham? How does that kind of building get enforced, the kind of building regulations you’re talking about? ROGER BILHAM: Building inspectors are designed to come and watch every stage of a building’s assembly in the US. You can’t put a building up in California, or in Colorado, even, without someone watching over your shoulder every step of a moment. You can’t go to the next step until you’ve received your certificate. In a place like Karachi or Tehran, building codes are now being enforced, and that’s something that’s happening officially. However, in some parts of the world, it’s possible to talk to your building inspector and say, “Why don’t to come tomorrow, after I pour the concrete? Here’s, you know, a few hundred dollars to look the other way.” And you might think, well, how can anyone be so stupid as to assemble a building without sufficient strength? The answer is, you can save money. And in the developing nations, there is this battle between what should be done and human nature, trying to either overtly make profits or covertly just to save money for the builders. You know, very often these— AMY GOODMAN: And also the issue of poverty. ROGER BILHAM: Yes. In Haiti, seismologists, my colleagues, told the Haitians that, in fact, large earthquakes were overdue, and they had happened a few hundred years ago, and there was enough strain now developed at the plate boundary to repeat a sequence of events that happened in the 1700s. Well, this knowledge is like kind of “dream on.” There are so many problems that Haiti had that even if they had started to act on retrofitting these buildings, it would have taken two, three decades. And there was no money for this. There are much more pressing issues. AMY GOODMAN: Finally, are there manmade situations or phenomena that are increasing the number of earthquakes? Does anything human beings do on earth have an effect on earthquakes, the number of earthquakes or their intensity? ROGER BILHAM: Not really. I can’t say that it doesn’t happen at all. If you build a very large dam, you sometimes trigger an earthquake. But what we’re watching is just the relentless movement of the plates. And what the earth has in store for us are usually a hundred magnitude-7.0 earthquakes a year. Our future disasters depend whether those earthquakes occur close to cities that are vulnerable to shaking, or whether they occur away from these cities. And it’s a hit-or-miss problem. But I forecast that it is possible now to have something that has never happened in earth’s history: an earthquake killing perhaps a million people. And how can you make such a ridiculous prediction? The answer is that never before have we had such large populations at risk from earthquakes, cities of 12 million. And there are many cities like this, and several of them, like Istanbul and Tehran, have a history of damaging earthquakes, and we may well see the effects of corruption and bad building practices revealed only after these earthquakes have struck. AMY GOODMAN: Finally, do you predict an earthquake in the United States anytime soon? ROGER BILHAM: Well, we’re very careful not to predict earthquakes. We tried that with a harmless earthquake in a field of cows at Parkfield a few years ago and failed miserably. What we can do, though, is forecast earthquakes, meaning that we know earthquakes will occur in something like a thirty-year window. And on the San Andreas Fault, of course, there are a couple of large earthquakes overdue, one near Palm Springs. It might reach up into the LA region through Palmdale and so on. That earthquake is known to be ripe, sufficiently mature to happen any day. It may not happen for a hundred years, but it’s certainly something they’re expecting. And, of course, earthquake resistance is pretty good in LA. I mean, the houses are made of wood, and earthquake-resistant design prevails throughout. But there is a much larger earthquake that could occur, and that is from Cape Mendocino northwards through Oregon, up to Washington state. We are expecting in this country a magnitude-9.0 earthquake. This may—this, again, could occur now; it may not occur for a hundred years. But occur, it will. And when it does, it will test those building regulations that have been put into effect in places like Seattle. There is a large building stock that hasn’t had the benefit of earthquake-resistant construction from the start. One can think of a lot of masonry buildings that will be damaged. There will also be a very large tsunami. And yeah, this is something that is definitely going to occur in our future, or the next generation. And I think we are more or less ready for it, certainly much better prepared than Haiti and as well-prepared as Chile. AMY GOODMAN: Roger Bilham, I want to thank you for being with us, professor of geology at the University of Colorado in Boulder, co-author with Susan Elizabeth Hough of After the Earth Quakes: Elastic Rebound on an Urban Planet.
