Hélène Le Mével Talks Gravity, Magma, Volcanoes at Broad Branch Road

The Carnegie Broad Branch Road campus hosts Neighborhood Lectures in the fall and spring, welcoming friends and neighbors and providing an opportunity to get up close and personal with Carnegie scientists.
Tuesday, April 30, 2019 

Hélène Le Mével presented a talk titled, “The gravity of volcanoes: using gravity data to probe magma reservoirs,” on April 25 at the Carnegie Institution for Science’s Broad Branch Road (BBR) campus as part of the Spring 2019 Neighborhood Lecture Series hosted by the Department of Terrestrial Magnetism and the Geophysical Laboratory.

The latest addition to DTM’s group of Staff Scientists, Le Mével gave a quick introduction of gravity and the scientists who study it. She also emphasized the importance of Earth’s gravity data for volcanology.

Le Mével also presented an overview of the tools and instruments volcanologists use to measure gravity data. These included satellite observations and measurements from the ground. “Gravimetry is very powerful to image magmatic systems and the active processes taking place in the magma chamber,” she said.

Le Mével (left) mingled with the audience after the lecture and showed DTM’s gravimeter, an instrument that she uses to gather gravity data in the field. Photo by Roberto Molar Candanosa, Carnegie DTM.

A volcano geodesist, Le Mével’s research focuses on understanding the surface deformation signals observed at volcanoes to infer the ongoing magmatic processes occurring in the underlying reservoir.

“Magma has a lower density than the surrounding rocks, so it would create a negative gravity anomaly due to that lower density,” Le Mével said. “It means that if we measure gravity at the surface of a volcano, we can actually see what the density difference is underground.”