CAREER: Investigating composition and rheology of circum-Pacific mantle wedges with body-wave attenuation

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Seismic observations help us understand the geological processes in subduction zones, where megathrust earthquakes occur and most volcanoes form. Seismologists usually measure seismic waves propagating in rocks to probe the temperature, composition, and other properties of the Earth. Yet many details of the subduction processes remain unknown partly because interpreting these velocity measurement are sometimes ambiguous. Seismic attenuation measures how a seismic wave loses energy as it moves through the Earth, and these measurements may help to reduce some of the uncertainties we have in observing and interpreting seismic signals. In particular, by combining velocity and attenuation measurements this project has the potential for detecting magma, water, and oxygen associated with the formation of volcanoes and earthquakes. This project will integrate research in seismic attenuation with an education plan that will develop a diverse geophysics workforce at Michigan State University (MSU). This work helps to address grand challenge science questions about tectonics, earthquakes and volcanoes highlighted in the Earth in Time report from the National Academies of Science, Engineering, and Medicine. The primary research goal is to conduct a series of attenuation studies on regional and global scales. The project will image the attenuation structure of multiple subduction zones surrounding the Pacific Ocean, with three focus sites of Tonga, Alaska, and the Pampean flat slab segment of the South American subduction zone. These systematic investigations will advance our understanding of seismic interpretation, upper-mantle dynamics, subduction processes, and material recycling in the Earth’s interior. The education component of this project raises awareness of geophysics as an area of study for students in STEM. This project will work with the MSU Science Theatre, an undergraduate student organization, develop several geophysics demonstrations for use on campus and at local elementary schools. Second, the PI will develop a junior-level modular course to prepare geoscience students with much-needed quantitative skills. Third, this project will also provide research opportunities for undergraduate and graduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.