Richard J. O’Connell, a pioneer of global geodynamics, passed away in 2015. Over the course of a scientific career that began when plate tectonics was just being discovered, he played a key role in shaping the emerging theories about the dynamics of Earth’s interior. He leaves behind a strong and lasting legacy that embodies the qualities of his scholarly career and refined approach to life. This legacy was celebrated at a remarkable gathering at Harvard, the Rickfest, shortly before his death.
Rick grew up in Montana in a town where his father was the sheriff. After a Ph.D. program that took him farther west to the California Institute of Technology (Caltech) and postdocs at the University of California, Los Angeles, and Caltech, he joined the faculty of Harvard in 1971, where he would be active as a scholar for the next 4 decades. He pursued a number of beautiful problems that lent themselves to elegant and insightful solutions, demonstrating a remarkable talent for distilling fundamental physical rules from complex Earth science phenomena.
Eclectic Interests, Expressed with Simplicity
Rick’s earliest contributions integrated measurements of plate motion, Earth’s gravity field and shape, and newly emerging seismic images of Earth’s interior with the equations describing viscous flow to draw a connection between global-scale observations and mantle dynamics. With then grad student Brad Hager, he laid the foundations of global mantle circulation modeling. This approach of estimating plate tectonic driving forces and how they are expressed at the surface of the Earth is used widely to this day.
Later work with Bernhard Steinberger of the GFZ German Research Centre for Geosciences in Potsdam set the stage for exploring how mantle plumes feeding hot spot volcanism are swept up in large-scale flow patterns (advected in the mantle wind). Rick and Bernhard also explored how these movements affect the orientation of Earth’s rotation axis with respect to the solid envelope of the lithosphere. Rick’s most widely cited contributions are a series of landmark papers with his Harvard colleague Bernard Budiansky on the mechanical and thermodynamic properties of materials containing cracks and inclusions.
Rick’s scientific interests ranged wide, from the measurement of seismic wave speeds in the laboratory to exoplanets. At the heart of his papers is a philosophy that models should be as simple as needed to provide insights into the processes that matter. His contributions were recognized by the highest honors in his field, including the Lehmann, Day, and Love medals of the American Geophysical Union (AGU), Geological Society of America, and European Geosciences Union, respectively.
Mentoring, Teaching, and Broadening the Field
Perhaps Rick’s greatest impact on science was his nurturing, directly and indirectly, of an expansive network of students and students of students through at least five generations. His unfailing support of unconventional ideas, his dedication to what might be called learner-centric study, and his ability to spot the most fundamental relationships that govern how systems behave permeated his approach to mentoring and teaching.
He shared his appreciation for interdisciplinary science more broadly with the scientific community: He served as a founding editor of AGU’s first online journal, Geochemistry, Geophysics, Geosystems; he helped to establish the National Science Foundation’s Cooperative Studies of the Earth’s Deep Interior (CSEDI) program; and he met the challenge of bringing space-based geodesy to the Earth sciences.
Most of Rick’s former students can recall laying the foundations for their scientific advances by working through a derivation on the blackboard. This “blackboard physics” approach applied not only to graduate education (and the long-planned textbook that remains unwritten) but also to Rick’s well-loved undergraduate classes aimed at nonscience students.
Strength, Humor, and Integrity
Rick leaves behind his wife, Susan; son, Brian; stepdaughter, Lily; sister, Pat; niece and nephew, Shannon and Ian; and stepson by marriage, Tom. Those of us who got to share time with Rick during the few years that he battled severe illness stand in awe of how his gentle nature, good spirit, humor, and love for single malt remained strong and steadfast until the very end.
Rick was a cowboy in the very best sense of the word: unassuming, modest, and quietly good-natured but possessed of strength, perseverance, and conviction to always do what was right and to do things in the right way. He has inspired generations of scientists to pose challenging questions and then to pursue them with the utmost integrity and respect for the scientific endeavor.
—Michael Manga (email: [email protected]), Earth and Planetary Science, University of California, Berkeley; and Thorsten W. Becker, Institute for Geophysics and Department of Geological Sciences, Jackson School of Geoscience, University of Texas at Austin