Dr. Fischer is renowned for her research on Earth’s upper mantle dynamics, the structure and evolution of continental lithosphere, and the dynamics of subduction systems. Over her career she has clearly made “outstanding contributions to the understanding of the structure, composition and dynamics of the Earth’s mantle,” the hallmark of the Lehmann medal.

Fischer’s work contributes immeasurably to understanding major uppermost-mantle discontinuities. Her group has shown what these signals consist of and has constructed credible geodynamic hypotheses for them. The community would pay far less attention to these features had it not been for the groundbreaking work by her and her students. In subduction zones and back arcs and around continents, she has been one of the pioneers in the innovative use of shear wave birefringence (“splitting”) to understand mantle flow. Her work has always been intimately and quantitatively tied to geodynamics, investigating such problems as subarc distributed flow, interaction of slabs and asthenospheric flow, flow in back-arc spreading, and localized versus distributed deformation in the mantle. She has pioneered the design of imaging arrays uniquely structured to resolve major questions about the origin and evolution of continents. Beginning in the early 1990s, a series of projects across North America and elsewhere displayed the value of thoughtful experimental design carefully planned to test interesting geodynamic problems.

In all of these cases, what sets her contributions apart is her ability to connect careful seismic observations to the underlying geodynamic processes. These studies have fundamentally changed our thinking of what is a continent and the role of the mantle in continental stability. What makes Professor Fischer a great scientist is not just the scope and innovation of the projects she has undertaken but the care, thoroughness and creativity through which she uses seismic signals to directly test geodynamic hypotheses. Every paper by her or any of her students is worth reading. In that context, Professor Fischer is the consummate colleague and mentor. She has mentored a long list of distinguished graduate students, undergraduates and postdocs, bringing out the best in all of them. In summary, Professor Fischer well deserves this award for her leadership and for seminal discoveries in the structure and behavior of Earth’s upper mantle.

— Geoff Abers
Cornell University
Ithaca, New York

Thank you, Geoff, for your generous citation. I am deeply honored and humbled to receive this medal, especially given the many deserving colleagues in our field and because Inge Lehmann was a true pioneer, both for her work on Earth structure — including finding the inner core — and as a woman in geophysics. I share this award with the wonderful students, postdocs and collaborators with whom I have worked over the years. Thank you for your talent, creativity and dedication. Discussing research with you is a high point of my day, and watching your careers flourish has been a highlight of my life. I would especially like to recognize former and current Ph.D. students and postdocs: Xiaoping Yang, Matthew Fouch, Aibing Li, Catherine Rychert, David Abt, Heather Ford, Julia MacDougall, Emily Hopper, Junlin Hua, Hannah Krueger, Isabella Gama, Sarah Bowers, Stéphane Rondenay, Ved Lekic, Margarete Jadamec, Nicholas Mancinelli, Zachary Eilon, Eva Golos, Kai-Xun Chen and Michael Mann. I am lucky to have spent most of my career at Brown, immersed in great colleagues with exciting ideas. Special thanks to Don Forsyth for his kind, but persistent, skepticism; Marc Parmentier, Greg Hirth and Alberto Saal for their insights about the mantle; Colleen Dalton for her excellence as a seismologist and collaborator; and Jan Tullis for many happy years of co-teaching. Understanding Earth’s interior is a team sport, and I am grateful to my collaborators around the world. I wish I could recognize you all by name. I will highlight Geoff Abers, who has been an inspiring colleague in our studies of subduction zones. Other fundamental ingredients are the data and instrumentation provided by the international seismological community, in particular by the Incorporated Research Institutions for Seismology (IRIS), and now by the EarthScope Consortium. Our traditions of open data and community-led governance are essential. I owe so much to Tom Jordan, Marcia McNutt, Ken Creager and Mike Purdy for their mentoring and support during my Ph.D. years and to Emile Okal for sharing the beauty of seismology when I was an undergraduate. Profound thanks to my spouse, Mary Alice McGee, for three plus decades of happiness and home. Finally, to our younger colleagues, if you have felt that you do not fit in science because of any aspect of who you are, please know that you do. To all, let’s continue building pathways to rewarding careers where everyone feels they belong, through listening, empathy, funding and action.— Karen M. Fischer, Brown University, Providence, Rhode Island