James R. Rice Receives 2012 Walter H. Bucher Medal: Citation

Eos, Vol. 94, No. 1, 1 January 2013

James R. Rice Receives 2012 Walter H. Bucher Medal James R. Rice was awarded the 2012 Walter H. Bucher Medal at the AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif.The medal is for “original contributions to the basic knowledge of the crust and lithosphere.”

PAGE 8 Citation Jim Rice’s long and distinguished record of seminal theoretical contributions to our understanding of fault and earthquake mechanics is unprecedented. His work has influenced the entire community working on earthquake science. It is hard to imagine how any single individual in the future could ever come close to making so many fundamental advances in this field. He focuses on the most important problems and advances our understanding of them and their solutions by insightful analysis using many mathematical and numerical techniques, supported by his encyclopedic knowledge and understanding of all relevant theoretical, experimental, and observational information. His contributions to geophysics include not only his own personal research but the influence he has had on many exceptional students, postdocs, and collaborators who are leaders in the field. There are so many of these that I will mention none, for lack of space and lest I leave important ones out! Jim started in engineering and began working on earthquake problems while at Brown. After moving to Harvard he gradually shifted nearly all of his research to geophysics. His more than 105 strictly geophysical publications are less than half of his total publication list, which has more than 250 entries! His engineering mechanics papers are extremely influential in that field and many of them also indirectly influence the geophysics literature. Throughout his career Jim’s papers have defined the cutting edge of research. I can only allude to a few of his contributions here. Jim’s first work in geophysics involved the interrelationship between pore fluid pressure, dilatancy, and strength of saturated rocks. These topics frequently have been the theme of his papers ever since. The contexts include the absolute and relative weakness of the San Andreas Fault, the influence dilatancy has on fault stability, and the role possibly played by thermal pressurization of pore fluid on earthquake nucleation and during dynamic earthquake rupture. Another set of Jim’s influential contributions are his many papers on rock friction, both rate and state friction and highvelocity friction, and their use in earthquake simulations. These include the behavior during a sequence of earthquake cycles and what can occur during a single dynamic rupture, for example whether ruptures propagate as

expanding cracks or as self-healing slip pulses, the role of elastic contrast on changes in faultnormal stress and rupture directivity, the influence of initial stress orientations and rupture velocity on a fault’s tendency to branch dynamically, and the off-fault damage produced by dynamic rupture propagation. Jim’s recent theoretical work on the role of friction and of pore pressure addresses one of the hottest topics in seismology and tectonophysics today, the origin and significance of episodic tremor and slip. Jim is an extremely kind and gentle person and a delight to work with. He not only writes excellent and readable papers, he gives lectures of exceptional and legendary clarity on very complex problems. Jim is not only an intellectually gifted individual, he works nearly nonstop. As an example to others with lesser talents, which includes most of us, he is an inspiring example. —TERRY E. TULLIS, Brown University, Providence, R. I.

Response Thank you, Terry, for those generous remarks, also for easing me into geophysics many years ago at Brown and for the friendship and wonderful exchanges on friction, lab things, faulting, and earthquakes over the years since. Charles Frank of Bristol, a personal hero who contributed greatly to geophysics, also pioneered understanding of line defects, called dislocations, in crystals. Those defects enable plastic flow, reproduce, and facilitate growth. Frank had a famous quip about crystals, defects, and people, which, given the focus of the Bucher Medal, I could paraphrase as “the crust and lithosphere are like people: it’s their faults that make them interesting.” My route to faults was circuitous: I came as an engineering Ph.D. from Lehigh to Brown in 1964 with a strong grounding in continuum mechanics and related mathematics. At Brown I built expertise in materials physics and directed that toolbox to cracking and plastic flow in engineering metals. That went well but, gradually, I decided to focus some on Earth processes, too. I didn’t have a clear idea how to do that but, with brilliant students and colleagues, tried to understand why deformation of soils and rocks is often localized into shear bands or faults, how pore fluid infiltration would interact with dilatancy of such media, causing time-dependent failures, and how that might underlie progressive extension of slip surfaces in landslides. Around then the

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James R. Rice dilatancy mania hit earthquake science. One couldn’t help reading, even in newspapers, about rock dilatancy, pore fluids, and earthquake prediction being just around the corner. I realized that I was developing just the tools to enter the fray. That focused me on earthquakes, or at least half of me: I continued, at Harvard to where I moved in 1981, a juggling act, staying simultaneously active on fracture in both seismology and engineering. Gradually, since the new century, I seem to have shifted entirely to Earth science, now including, along with earthquakes and a bit on tsunamis, mechanisms enabling rapid ice sheet motion and topics intermingling geomechanics and hydrology. I deeply appreciate how welcoming and encouraging the geophysics community was. My toolkit was surely as relevant there as in engineering, but I was without credentials and had gigantic gaps in knowledge, some occasionally exposed as unfilled still. That welcoming group, beyond Terry and his colleagues at Brown, includes marvelous people at USGS starting with Bill Stuart and then a host of others that I better not try to name, Paul Segall and his colleagues in geophysics at Stanford, and many others. I’ve been blessed, too, with some wonderful colleagues at Harvard and Brown. Most of all, I have a soulmate in life, a seismologist with equal passion for all things relating to earthquakes and the like, and for many more placid things, too—music not the least—that being my wife, Renata Dmowska. Should I close with something for the young, like the incredible power of getting a strong grounding in math, mechanics, and other physics theory, which perhaps worked for me, or instead just ask them for help swimming into the modern data-swamped era? —JAMES R. RICE, Harvard University, Cambridge, Mass.