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On the Ground With Eric Calais, U.N.'s Geophysicist in Haiti
13 September 2010 1:41 pm
In August the United Nations brought in geophysicist Eric Calais of Purdue University in West Lafayette, Indiana, as yearlong scientific adviser to help Haiti vamp up its disaster preparedness in the wake of the magnitude-7.0 quake that hit the poverty-stricken country in January. Calais spoke with ScienceInsider about his work, his discoveries about the quake, and why an even bigger one could be on the horizon for Haiti:
Q: Can you describe the beginning of your work in Haiti?
E.C.: The week after the earthquake, I was in Haiti for purely scientific reasons to measure the ground damage caused by the earthquake and try to understand what happened during the earthquake. ... There were very few scientists in the field at the time. There was a lot of information flowing at [policymakers], and it was difficult for them to sort through that information and decide which was correct or incorrect, or useful or not so useful. So I played that role for the first 5 weeks I was there.
Q: When did the U.N. start talking about bringing you on as an adviser?
E.C.: Somewhere in April, May this year. ... There was a need to have someone in Haiti who would be able to provide scientific advice while interacting with the U.N. and its agencies as well as the Haitian government, someone with enough understanding of the politics of Haiti and the institutional intricacies of Haiti who also had a strong scientific understanding of the earthquake hazards.
Q: You've been there for a month now. Can you give some examples of advice you've given to the Haitian government and the U.N.?
E.C.: One of the examples is the importance of what we call in technical terms microzoning, which means that before you decide how and where to rebuild a large city in an earthquake-prone area, you need to know what the characteristics of the subsurface are in terms of the reaction of the ground to seismic waves as they pass through. Some terrains are really good, really stiff and do not amplify seismic waves, but some do in ways that are very complex. Depends on the type of soil, depends on the topography, depends on many factors. ...
We know that Port-au-Prince will be impacted by a major earthquake in the future. Can't tell when, but we know it will happen and we know it will be worse than what happened on Jan 12, 2010. So the bottom line for us as far as urban planning is this microzoning.
Q: How much do we know about the next earthquake to hit Haiti?
E.C.: We know from our evidence that the southern part of Haiti, the southern peninsula, the region really close to Port-au-Prince, is one of those [earthquake-prone] areas. We also know that the northern coastline is one of those areas ... because it is building up that elastic energy that will eventually be released in an earthquake. Scientists know that it will happen again, we know the possible magnitude of the earthquakes to come, and we know that those magnitudes are greater than 7. So we know that Haiti needs to prepare for earthquakes of magnitude greater than 7.
Q: Do you think Haiti will be better prepared when the next one strikes?
E.C.: When engineers talk about reconstruction and about buildings, they think about the 50-year time scale because that's the average lifetime of a building. So within the next 50 years, the likelihood of another magnitude 7 is high. That is a scientific fact. Given that, there are two options: You ignore that threat and do business as usual, or you do not ignore that fact but try proactively to plan properly for the reconstruction and to build properly and to educate properly and to monitor earthquakes properly. So there are many things that need to be done in order to be ready when the next earthquake hits. Hopefully, it will hit very late in the future at a time when Haiti will be much more ready than it is now. ...
In my viewpoint, it doesn't matter when an earthquake will strike. What matters is whether the country will be ready to face that earthquake.
Q: What about your recent finding that the earthquake occurred not on the Enriquillo fault, but a previously unknown fault?
E.C.: [This discovery] is not a big surprise for two reasons. Reason number one is that there are other faults beside the Enriquillo that we know of that we know are active. And number two, this is not the first time at all that an earthquake highlights a fault that we didn't know about before. Think about Northridge 1994. ... It took an earthquake to tell us this fault is active, it's capable of producing an earthquake. So this happens all the time, unfortunately.
Q: Do you think reconstruction is moving quickly enough?
E.C.: It is a little slow to my taste, but I understand that there are other considerations that are at play here, and the government is under a lot of political pressure, social pressure. ... But at the same time, they should not forget that there are important steps that have to be taken.