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.
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
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.
Marisa Lubeck: What was unique about your trip to Haiti as compared
to other international earthquake response trips that you have made in
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.
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.
So 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
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?
Walter 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.
We 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.
On 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.
Marisa Lubeck: Thanks for speaking with me today,
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.
Description: In response to the 7.0-magnitude earthquake that tragically struck Haiti on January 12, 2010, the U.S. Geological Survey has coordinated a series of trips to the country to characterize the damage and install seismic instruments for earthquake monitoring. USGS seismologist Walter Mooney, who returned from the first of the series of trips in early February, discusses the USGS role in the aftermath of the Haitian quake.