Help in Haiti - The Role of Science

 

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Marisa Lubeck: Welcome and thanks for tuning in to this episode of CoreCast. I'm Marisa Lubeck.

In response to the 7.0-magnitude earthquake that tragically struck Haiti on January 12, 2010, the US Geological Survey has coordinated a series of trips to the country to characterize the damage and install seismic instruments for earthquake monitoring.

I'm here with USGS seismologist Walter Mooney, who returned from the first of the series of trips in early February, to discuss the USGS' role in the aftermath of the Haitian quake.

Welcome, Walter.

Walter Mooney: Hello, Marissa. It's a pleasure to have a chance to talk with you today.

Marisa Lubeck: You recently returned from a trip to Haiti in early February. What research did you focus on there and what were the key findings?

Walter Mooney: When we went to Haiti, we had some very clear objectives in mind. The first thing we wanted to do was to asses the damage the damage to the ocean port because that needs to be re-established to bring in humanitarian aid.

01:00

We also wanted to asses the causes for the extensive damage to the buildings and roads and similar kinds of structures. And we wanted to deploy portable seismographs so we could record the shaking from aftershocks.

What we found was it will be possible to open the port by using standard and well-established marine engineering design. That's some good news. We also found that well-engineered buildings did not suffer much damage. Again, good news because it means that even though the destruction was very widespread, if the buildings are designed properly, they will survive these kinds of earthquakes.

And finally, we discovered that there were many strong aftershocks that followed the main shock of January 12. And from the measurement of these aftershocks, we could begin to map out those parts of Port-au-Prince and neighboring communities which have stronger shaking and those regions that have lesser shaking. And all of these information is useful while we think about reconstruction.

02:01

Marisa Lubeck: What was unique about your trip to Haiti as compared to other international earthquake response trips that you have made in the past?

Walter Mooney: Well., I've made a lot of trips after major earthquakes and I've seen a lot of damage. But I've never seen anything that is quite as extensive and severe as the loss of life and destruction of buildings that one encounters in Haiti. There were something like more than 150,000 casualties, 200,000 buildings destroyed. All of these exceeded by a wide measure any earthquakes that I have ever seen.

Secondly, the level of humanitarian effort necessary to care for the half million homeless and displaced persons is really staggering. And what we learned was this particular earthquake was extremely sudden and sharp and abrupt and strong in its shaking, with many of the buildings collapsing within the first five or six seconds of the earthquake.

For a great many people, there was literally no chance to escape to safety. So what I'm hoping is that the work that I'm doing with my colleagues can really contribute to avoiding another similar kind of disaster like this in Haiti.

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Marisa Lubeck: In the aftermath of this devastating earthquake in a country struggling to respond in even the most fundamental of humanitarian needs, why is this sort of scientific research important? Should science even be a concern right now?

Walter Mooney: Science is of great concern following an earthquake like this because there are some things that scientists and earthquake engineers are uniquely capable of studying.

For example, we can help establish what are the engineering requirements to open that ocean port so that humanitarian aid can come in by sea in much larger volumes that can be done by air.

Also to determine the true safety of those structures that are still standing but for which we don't really know without an evaluation whether they are safe to reoccupy at all.

And we can study the strength and number of aftershocks and the distribution of shaking all throughout Haiti so that we can identify those sections of Haiti with kind of soft, marshy soil that really should not be used in the future for building structures and residences.

04:13So all these things are really very useful and they complement the humanitarian efforts.

Marisa Lubeck: What will USGS scientists be studying during this next trip to Haiti? What sort of questions weren't answered during this trip?

Walter Mooney: The first team of scientists that went down to Haiti consisted of a mixture of seismologists and earthquake engineers. And we were able to do a certain limited set of things.

The next team to go to Haiti will also include geologists who will go out and map all of the active faults as well as identify those regions that are at high risk for future landslides. 

So the next team will have a more geological component.

Marisa Lubeck: What sort of geological factors should be taken into consideration during the rebuilding process in Haiti?

05:00Walter Mooney: There are a number of geological factors that we have to think about very carefully. For example, the safest places to rebuild are going to be near hard rock sites. Hard rock is stable and has less shaking during an earthquake. While the worst place to build will be those regions with soft sediments and a shallow water table. Both of these we can determine quite easily.

Another geological factor is proximity to the fault zone. As you can imagine, the closer you are to an active fault, the stronger will be the ground shaking. So there are indeed several geological factors that are important to consider during reconstruction.

Marisa Lubeck: What technologies or other services can the USGS offer Haiti to help earthquake response in the future should another significant earthquake strike in the area?

Walter Mooney: There are a lot of services and technologies that USGS can offer. For example, we can help install a seismic monitoring system that will help provide notification of an increase in seismic activity. It will also measure quantitatively the amount of ground shaking that's occurring in buildings so we can see how much they are being disturbed by these earthquakes.

06:08We can use global positioning satellite measurements, also known as GPS measurements, to study and measure the accumulation of strain of the stresses on the geological faults in the area. And we can make what we call earthquake seismic hazard maps, which basically are colored maps that show those regions in Haiti which are at higher risk for strong ground shaking and those regions which are at much lesser risk.

All of these services and products can really help a lot to reduce the hazard from earthquakes in a future event.

Marisa Lubeck: Why was the devastation in Haiti so great as compared to places such as California which experiences strong earthquakes frequently with significantly less damage?

Walter Mooney: People in Haiti have suffered a lot from hurricanes. And so uppermost, by far, on their minds, had been the risk from strong winds due to hurricane effects.

07:06On the other hand, the region had been relatively quiet with respect to earthquake activity for the last many decades. The result was they made very heavy buildings with heavy concrete roofs which are very vulnerable to collapse during strong ground shaking.

So the message is even though in Haiti where the earthquakes of this magnitude are relatively infrequent, they still have very major consequences. And somehow, the USGS and other agencies need to get that message out to people that even a rare event must be planned for and this is something that we have seen now several times, not only in Haiti but in China and other regions of the world.

Marisa Lubeck: Where can listeners turn for more information on this and other earthquakes?

Walter Mooney: There's a lot of information on the USGS website and that could be found in USGS.gov. Go to the section which is called 'Earthquake hazards' and there, you'll find a lot of information about the disaster in Haiti as well as other recent earthquakes.

08:09Marisa Lubeck: Thanks for speaking with me today, Walter.

Walter Mooney: You're very welcome. It's a pleasure.

Marisa Lubeck: This podcast is a product of the US Geological Survey, Department of the Interior. I'm Marisa Lubeck. Thanks for tuning in.

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Additional links of interest:

• Open-file report
• USGS Scientists, Research Help Haiti Reconstruction (news release)
• Also, for information on the recent Chile Earthquake listen to Episode 122 of CoreCast