Geophysicist Maria Beatrice Magnani has been an assistant research professor at
the Center for Earthquake Research and Information (CERI) at the U of M since January
2006. After studying plate boundaries all over the world, Dr. Magnani recently had
a major discovery of a previously unknown fault line beneath the Mississippi River.
She has also been featured in a PBS documentary and on their Web site as an “Ask the
Maria Beatrice Magnani
How did you become interested in geology?
I like to travel and I’ve always had a passion for science and exploration. My choice
to become a geologist and a geophysicist was mostly influenced by my science professor
in high school. He was (and still is!) a geologist and explained volcanoes, subduction
zones and earthquakes as being linked phenomena through the plate tectonics theory.
The idea that I could travel the world for work was very appealing. Probably growing
up in a seismically active country like Italy added the extra bonus.
Tell us about yourself and your educational and research background.
I have a master’s in geology and a PhD in earth sciences, both from the Universita’
degli Studi of Perugia, Italy. My research has mostly focused on tectonic studies
on the evolution and deformation of continents and their margins.
How did you end up at the U of M from your native Italy?
As part of the PhD in Italy, I was selected to spend two years at the Department of
Geological Sciences at Cornell University to carry out my research and fulfill my
coursework requirement. After graduation, I moved to Rice University to pursue my
post-doctoral studies. After several projects and papers, I decided to move on and
start my own research group. That’s when I came to CERI.
You’ve studied the Apennine Mountains in Italy, the Rocky Mountains and the Caribbean/South
American plate boundary near Venezuela in South America. You’re now working in the
New Madrid Seismic Zone. How does it compare to working in the others?
My research has focused in areas of large deformation, along plate boundaries and
on mountain belts, where the general tectonic processes are understood and we are
now working on important details. The New Madrid Seismic Zone instead is an area where
deformation is subtle and more challenging to understand because evidence is controversial
and difficult to reconcile. Intraplate seismicity and deformation is one of the last
frontiers of plate tectonics, as we still have to understand the fundamental processes
responsible for the large earthquakes that occurred away from plate boundaries.
You recently had a major discovery of a previously unknown fault line, the Meeman-Shelby
Fault, a 30-mile long fault below the Mississippi River along Shelby Forest and the
Shelby County border that if active, could cause a 7.0-magnitude earthquake. Tell
us about that find.
In summer 2008 together with a team of scientists from the University of Texas at
Austin, I acquired a long profile (200 miles) along the Mississippi River, from Caruthersville,
Mo., to Helena, Ark. It was innovative research, the first of its kind to collect
high-quality seismic reflection data along a large river. The profile identified two
previously unknown faults exhibiting a long history of deformation and very recent
activity. The most puzzling part about these two faults is that they are not located
within the New Madrid Seismic Zone, which is the area where seismicity is recorded
today. One of these faults, the Meeman-Shelby Fault, trends NE-SW and is located very
close to Memphis. With a length of approximately 30 miles, the fault is capable of
generating a 7.0-magnitude earthquake. The fact that the fault has moved in the last
few thousand years poses the question whether the fault is still active and will move
again soon. To answer these questions, I am planning on acquiring new seismic data
across the fault, this time on land, and identify the precise location of the fault,
so that geologists can trench the structure and date the recent deformation with greater
If the Meeman-Shelby fault became active and caused a 7.0-magnitude earthquake in
the Memphis area, what would that look like?
First, we don’t know whether the fault is inactive or quiescent. Faults like this,
far away from the plate boundaries, have a long repeat time. They might be quiescent
for 1,000 to 3,500 years and then, all of a sudden, trigger a magnitude 8.0. The data
shows that the fault we discovered has a long history of activity.
Should that fault become active, it would be capable of generating a 7.0-magnitude
earthquake, which would cause widespread damage, especially in areas prone to liquefaction
as is the case for most of the Mississippi River alluvial plain. Memphis is located
outside the alluvial plain, on top of the bluffs, and liquefaction may be less widespread.
Studies show that this may be due to the presence of a stiff layer of loess deposited
on tops of sands. Those locations where the loess has been incised and eroded, by
a river, for example, might experience more liquefaction than those areas where the
loess layer is still intact. I don’t know if many buildings will be standing. I sure
hope so! Several buildings in the Memphis area have been retrofitted to withstand
large accelerations associated with strong ground motion. The damage would extend
to an area beyond the city of Memphis to include bridges on the Mississippi River,
etc. An area from St. Louis to New Orleans would feel it. In the middle of the continent,
seismic waves travel very far because the continent is old, cold and rigid, and the
energy released by an earthquake is not attenuated much (or dissipated very quickly).
This is different from California, for example, where the crust is hot and attenuates
seismic waves much more efficiently. The interior of the continent is like a bell
that rings for long distances and for a very long time.
Haiti recently suffered a 7.0-magnitude earthquake. Have you seen any similarities
with the recent earthquake in Haiti to anything you’ve previously studied?
The earthquake in Haiti is similar to the type of earthquakes that are generated at
the plate boundary between the Caribbean plate and the South American plate. Similarly
to the boundary to the south, the plate margin between North America and the Caribbean
plate is the location of strike-slip movement along nearly vertical faults. Whether
these faults cut through the crust or are shallow features is still to be established.
Are you planning to study the geological impacts of Haiti in the future?
Yes. I’d like to study the crustal structure of the system of faults that were responsible
of the Jan. 12, 2010 earthquake.
You were featured in the PBS documentary, Earthquakes in the Midwest, and then on
PBS’s Nova ScienceNOW Web site as the “Ask an Expert.” People wrote in with questions
about the New Madrid Seismic Zone. How was that experience?
It was fun and challenging at the same time. People asked a variety of questions and
it was difficult to answer all of them clearly. I was surprised that so many people
watched the documentary and wrote in.
What do you enjoy doing when you’re not studying the Earth’s crust?
I like traveling, sailing and playing guitar.