Less than 24 hours after the quake hit, the death toll had climbed close to 10,000 and state media reported that in one county 80 percent of the buildings had been leveled. That casualty count is expected to rise still further as rescuers get closer to the epicenter of the destruction. Could some of the deaths have been prevented in this notoriously high-risk area? And what chances do those trapped under the rubble have of surviving the wait to be dug out? NEWSWEEK’s Katie Paul spoke to Weimin Dong of Risk Management Solutions, who has served on technical committees at the California-based Earthquake Engineering Research Institute and has studied earthquake-related insurance issues in China. Excerpts:
NEWSWEEK: This region suffered several smaller earthquakes earlier this year. Was it prepared for something like this? Weimin Dong: This is a moderate earthquake area, which in the Chinese design code is specified using an intensity number of 7 for new buildings. Beijing, for example, is 8, and other areas could even be a 9, which is much [more severe]. At the epicenter area of this earthquake the intensity was actually about 10. But the design required for this area is only for an intensity of 7, which I think explains a lot of the damage for the buildings in the area. That’s different from magnitude, since each earthquake has only one magnitude, while intensity looks at ground motion in areas far from the epicenter, which receive less intensity. Here, the highest intensity for this earthquake is about 9 to 10, and it goes down to 5.
Could you give a sense of how much worse a 9 or 10 is than a 7? It determines how much force a building will be able to resist. So if a building is designed for an intensity of 7, then for an intensity of 9 it will probably collapse or suffer severe damage.
And in this region most buildings are only built for an intensity of 7? That’s the best. China’s earthquake design code was not enforced until 1978, following the Tangshan earthquake. Before 1954 there was no design code. From 1964 to 1978 there was a very rudimentary design code. After 1978, that was a wakeup call. But in the rural areas a lot of the buildings are old and were built before that, and the requirement for intensity 7 is only for new building. Many of the buildings in the area were not designed for earthquakes at all.
How rural is the area? Could you describe the kinds of buildings one would find there? The city Chengdu, the capital of Sichuan province, is about 95 kilometers [60 miles] from the epicenter. This area has a lot of masonry building, brick building, adobe building. Some maybe have a wood frame building with some clay surrounding it. The buildings aren’t really engineered. They do have some reinforced concrete buildings that I saw in several pictures, but those were still built for an intensity of 7 and would not be strong enough to resist an intensity of 9 or 10. [Based on that] we shouldn’t be surprised that 80 percent of the buildings collapsed.
Why is the requirement only 7? Has the government not invested enough in this area? You cannot require all of the buildings designed to [be fully equipped], because it costs a lot. You have to have larger beam sizes and everything else, so it’s a cost consideration. After the Tangshan, China did spend a lot of money to retrofit brick buildings, which suffered the most severe damage during that earthquake. So when you go to China and see all these older brick buildings, there are concrete columns on the corner and ring beams around the buildings to try to keep the building from collapsing. They did a lot of this kind of retrofitting nationwide, but mostly in the cities.
How much of the destruction we’re seeing do you think could have or should have been prevented? That’s hard to say, because the existing building structures are much, much larger. It’s not like in Beijing or Shanghai—there they just pull down the old building and build a new high-rise. But in the rural areas the larger buildings are the older buildings. From the pictures of the schools, it seems like there was some kind of reinforcement, but it’s not well designed because in the steel bar there’s no confinement.
Is there still a chance that there could be a miracle rescue of those 900 kids under the school? I’ve seen a picture of the two kids that escaped from the school. What they said is that they just ran faster [than their classmates]. Maybe in the short term [they could be rescued], but if it takes too long, they could die. It didn’t seem like the schools were designed and built to satisfy the seismic code. I just looked at the ruins in the pictures, and it doesn’t seem like the building design considered the impact of earthquakes at all.
So it wouldn’t have withstood even an intensity of 7? No.
Given how active an earthquake region this area of the world is, were Chinese authorities adequately prepared to deal with the disaster? If earthquakes had hit [in this particular region] very often, they would have required higher design standards there. In the historical record the maximum magnitude is only 7.2 or 7.3. I think they’re doing as much as they can. I think it’s less than satisfactory in design code enforcement. But there’s just such a large stock of existing buildings, you cannot retrofit them all to modern standards. The Chinese government tried to do preparedness education in every city, so I know at least the government is requesting this, but whether or not the local townships are following it, I’m not sure.
How would you compare their preventive efforts to those that take place in other active earthquake zones, like, say, California? California is much better. In California we retrofit all of the masonry building. In San Francisco and Los Angeles we do that one by one. But China is such a vast area with so many millions and millions of these kinds of older buildings, I don’t think the Chinese government can afford to upgrade all of them. But they do try; I think it’s fair to say that.
