Searching for the Deep Roots of Arc Volcanoes, Geoffrey Abers Presents His Tuve Lecture
On Thursday, October 31, 2019, Geoffrey Abers, the William and Katherine Snee Professor in Geological Sciences at Cornell Engineering and visiting Merle A. Tuve Senior Fellow at DTM, gave his lecture titled “Searching for the Deep Roots of Arc Volcanoes: Results from iMUSH Seismic Imaging in the Washington Cascades.” Abers uses modern seismic instrument arrays to build high-resolution images of the Earth’s crust and mantle in order to understand the material and fluid cycles of the planet.
Many volcanoes erupt magma that ultimately originates from the mantle. According to Abers, seismic imaging has done little to show the deep crustal and upper mantle plumbing that would allow this magma to make its way from its origins deep within the planet to its volcanic destinations at the Earth’s surface.
Abers explored this pathway through the deployment of a massive 70-station broadband seismic array around Mount St. Helens called iMUSH (imaging Magma Under St. Helens). During the study, iMUSH was able to capture images of the crust and underlying upper mantle in unprecedented detail.
Curiously, this imaging revealed little evidence of the deep magma plumbing system beneath Mount St. Helens. While the images captured evidence for hot material east of Mt. St. Helens, along the line defined by other volcanoes in the Cascades arc, the mantle directly beneath the iconic volcano appears to be too cold to account for the observation of mantle-derived magma contributing to its eruptions. This result provides some of the strongest evidence yet that magma travels laterally in addition to vertically to get from the mantle to the eruptive centers along the volcanic arc.
What is a Tuve Lecture?
The DTM Tuve Senior Fellowship started in 1996 in honor of the late Merle A. Tuve, who served as DTM director from 1946-1966. Among his many scientific accomplishments, Tuve supervised the development of the proximity fuze during World War Two, and the design of a pressurized Van de Graaff generator, which achieved energies above 4 MeV. In 1942, he served as founding Director of the Applied Physics Laboratory.
Chosen at the discretion of the director of DTM, recipients of the Tuve fellowship are provided housing support and DTM resources during visits to DTM to work on problems of mutual interest with current staff members at DTM. Support for the fellowship program derives from the initial gift of former staff scientist and DTM Acting Director Tom Aldrich with donations from several DTM alumni and most recently gifts in memory of Erik Hauri. Like Abers, each Tuve Fellow presents their findings in a culminating lecture as a part of the DTM Tuve lecture series.