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 resolution.

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.