The Haitian Earthquake - A Week Later

 

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Marisa Lubeck: Welcome and thanks for tuning in to this episode of CoreCast. I'm Marisa Lubeck. As Haiti copes with the aftermath of the earthquake that struck 10 miles southwest of its capital of Port-au-Prince on Tuesday, January 12, 2010, the U.S. Geological Survey is working to gather information that can aid response efforts.

I'm here with Michael Blanpied, USGS Earthquake Hazards Program Coordinator, for an update conversation about the current situation in Haiti and to answer questions about the global picture.

Welcome, Mike.

Michael Blanpied: Hi, how are you this morning?

Marisa Lubeck: I'm well, thanks. As Haiti grapples with the aftermath of the seven magnitude earthquake, what's the risk of further aftershocks and what is the current aftershock count as of today, January 15th?

Michael Blanpied: Well, the devastation in Haiti has been quite considerable from the earthquake and aftershocks have been continuing. As of this morning there have been about 60 or 65 aftershocks in the magnitude 4.5 to six range and 13 of those have been magnitude five or above.

01:06

The rate of the aftershocks is tapering off as we would expect but we certainly expect aftershocks to continue for weeks or months. So while they don't pose the hazard that they did initially, we would expect there to be continued hazard from aftershocks in the coming weeks and it's something for people to be aware of.

Marisa Lubeck: What is the likelihood that Haiti will experience another event like this earthquake?

Michael Blanpied: The likelihood that there'll be another magnitude sevenish kind of earthquake is rather low but not zero. It happens sometimes that a large earthquake will be followed later whether it's days, weeks, or months later by another large earthquake that is triggered by the first sort of like a large late aftershock. However, that more likely not to happen than to happen. We're working hard to evaluate where that might happen if it did but at this point, our thinking is that that's fairly unlikely.

Marisa Lubeck: Has the government of Haiti been seeking any technical assistance from the USGS?

01:59

Michael Blanpied: Not at this point. Right now the Haitians are very focused on the search and rescue stage of the disaster and meeting immediate needs of the folks; food, water, medical attention. We won't expect the request for technical assistance until those immediate needs are met. So over the coming weeks as they begin to get their feet under them, we'll continue our conversations with USAID and with our colleagues in Haiti and see what we can offer that will help them as they recover from the earthquake.

Marisa Lubeck: Is the USGS using any tools to help Haiti prepare for additional hazards such as aftershocks, land slides, or possibly even a tsunami?

Michael Blanpied: What we are doing at the moment is providing information about the ongoing aftershock sequence as needed. We cannot predict when an aftershock will occur but we can certainly say how active the sequence is. This is an active sequence so we're providing information about that to those who would desire that information while they're on the ground conducting the relief effort.

Marisa Lubeck: Where else in the world could an earthquake similar to that which struck Haiti potentially occur?

03:01

What other nations are vulnerable?

Michael Blanpied: There's seismic hazards really in a lot of the worlds and there's great concern that an earthquake of this type could strike an urban area in a number of different places, in particular in Africa, along the East African rift. You may recall just about three weeks ago, there was an earthquake of moderate magnitude in Malawi that caused damage but this is an illustration of what can occur there.

China is very seismic reactive as the Sichuan earthquake of May 2008 illustrated and there's a long history of devastating earthquakes in China and certainly the danger there is large as ever. For also -- continued concern for Indonesia where there's the possibility of further large earthquakes that could cause both strong shaking and tsunami run-ups.

You may recall there was an earthquake in the mountains of Pakistan not long ago that killed a large number of people. And there's also fault lines that run near Tehran and there are hundreds of thousands of people there at risk.

03:59

There's really a large number of cities around the world that has lurking dangers from earthquakes. We have perhaps 15 earthquakes of this size every year and most of them wide of the mark. Unfortunately, every once in a while, there's a bull's eye and some of the cities that are sitting at those bull's eyes include, as I mentioned, Tehran, Istanbul, Turkey, Jakarta, Manila, Lima, Peru, Islamabad, Kabul, Managua and even in the United States. So this is a worry and we need to continue to look very hard at these areas and work very hard to prepare for those earthquakes so that they don't become disasters if they do occur.

Marisa Lubeck: Would you anticipate damage to be comparable on these areas?

Michael Blanpied: It really depends on the earthquake but the cities I've described do have significant vulnerability. The damage from an earthquake depends on two things. One is the earthquake itself; how big, how close, how much shaking, and the other is how resilient the infrastructure is in the area. Some of the older cities of the world especially in developing parts of the world have infrastructure that's really not built to standards that resist earthquake shaking.

05:06

So if we had a significant hit on a big urban area like that there could be really a significant damage that even exceed what we've seen here. For example, we have the City of Tokyo which is likely to eventually experience a very large earthquake. In that case, they've got a relatively modern and resilient infrastructure; the buildings are relatively well built. However, that is an incredibly large and densely built urban environment and the damage will be considerable.

A city like Katmandu in Nepal is very large concentration of people, high seismic hazard and construction that just isn't up to the par and there we would fear a very large humanitarian disaster if there was an earthquake there.

Marisa Lubeck: What is the likelihood of a magnitude seven earthquake happening in the United States similar to that which occurred in Haiti?

Michael Blanpied: The risk of magnitude seven-like earthquakes in the United States is lower once we get away from the tectonic plate boundary that runs up the West Coast.

06:03

However, there is appreciable seismic hazards in parts of the U.S. including along the East Coast. Back in the 1800s there were a couple of large earthquakes that struck, again the Charleston, South Carolina area. We don't understand those earthquakes very well because it was very poorly recorded at that time. We didn't have seismometers but we understand that there is a hazard there and need to be prepared for it.

There were earthquakes that struck in the New Madrid seismic zone which is a seismic reactive area near Memphis in 1811 and 1812. There were three at least large earthquakes that were magnitude seven or larger that caused very broad shaking in the Center of U.S. The area had a low population density at that time but geologists who have examined that area see evidence that those earthquakes have repeated over and over through the last many hundreds of years.

So as we approach the 200th anniversary of those New Madrid earthquakes, we're taking a hard look at that area and working hard to make people aware that there is a seismic hazard in the Central U.S. and that it would pay to pay attention to that to prepare for earthquakes, to strengthen the infrastructure and be ready because really an earthquake could occur at any time.

07:15

Marisa Lubeck: What did scientists learn from the 2004 Indian Ocean earthquake and tsunami that could potentially help relief efforts in Haiti? For example, what sort of technologies were developed to improve earthquake and tsunami detection and response?

Michael Blanpied: Absolutely the first result of the Sumatra earthquake and tsunami was just a global awareness of earthquake hazards that devastation was so stark and then lives lost were so great in that tsunami that the awareness of earthquakes and the need to prepare for tsunamis really went way up. In terms of technology, there were a number of advances that were made in that time since then. First is that both in the Indian Ocean and elsewhere, including in the Caribbean, there's been a great improvement in the rapid detection of earthquakes for tsunami warning.

The USGS installed nine improved seismometers to complete the monitoring network in the Caribbean and that information is flowing directly to the National Oceanic and Atmospheric Administration, NOAA, so that they can make rapid tsunami announcement as they did in this case.

08:19

If you will recall within four minutes of the earthquake, NOAA had issued a watch for potential tsunami in the adjacent islands that was later cancelled once the earthquake was determined for sure to have been under land. Another thing that we were able to do in Sumatra is improve our global monitoring. We have 150 seismometers around the globe that are streaming information in real-time back to our earthquake information center in Golden Colorado so we can very quickly determine location, magnitude, and shaking extent for earthquakes where ever they occur.

We also now operate that center 24/7 with the transmissions on the spot ready to go whenever the earthquake strike. Quite a bit has happened in the last five years or so and we can't do anything about reducing the risk that earthquakes are going to occur.

09:04

We are in a much better position to respond to them very quickly with information to direct relief efforts where needed.

Marisa Lubeck: What will scientists be trying to learn in the aftermath of this event in Haiti?

Michael Blanpied: Immediately what we're trying to learn is exactly what happened during that earthquake. We have information about the fault that broke from our understanding of the fault from prior geologic studies and I'll remind the listeners that this probably occurred along the Enriquillo fault zone which runs along that southern part of Haiti out along that peninsula west of Port-au-Prince and then it actually goes out to sea. It comes on to land again along the southern part of Jamaica to the southwest.

It's a very long fault zone and only a portion of it broke in this earthquake so one of the things we're trying to understand is how much of it broke and what are the implications of that for the unbroken parts of the fault that may also have been storing a lot of seismic energy.

10:00

Another thing we're looking hard at using satellite imagery and other means is the distribution of other hazards; liquefaction that may have occurred on the flat lands, port area of Port-au-Prince, where landslides may have occurred in the mountainous areas around and the distribution of damage; how far is it that the shaking was evidently quite strong based on the distribution of damage.

This is part of the world in which we have large earthquakes every once in a while but we've not have well-recorded earthquakes recently. So our understanding of how those earthquake waves spread over space following an earthquake is limited and when we have an earthquake of this type that was well recorded, we want to take full advantage of that to understand better earthquakes in the Caribbean and be better enable to then predict the likely effects from earthquakes that may occur in the future.

Remember our goal through all of this is to increase the resilience of the vulnerable parts of the world. We want to be able to give advice to the nations of the Caribbean on how to best prepare for the earthquake hazards that face the region, how likely are those earthquakes, how big, and what are some measures that can be taken to safeguard populated areas so that earthquakes don't become disasters.

11:13

Marisa Lubeck: Where can listeners turn for up-to-date information on the situation in Haiti?

Michael Blanpied: For technical information about the earthquakes and their effects, the best place to go is to usgs.gov with the direct link on to the Haiti earthquake magnitude seven or for all the earthquake information that we have about the recent earthquakes and others, go to earthquake.usgs.gov.

Marisa Lubeck: Thanks for speaking with us today, Mike.

Michael Blanpied: It's been my pleasure.

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

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Related Information:

 

• Magnitude 7.0 Haiti Region (earthquake event details and maps)