James R. Rice awarded 2008 Panetti-Ferrari International Prize for Applied Mechanics

Congratulations to James!

Congratulations to James on his wonderful Achievement

I take the liberty to post the following paragraphs written by several of us (Yehuda Ben-Zion, Alan Needelman, Paul Segall, Zhigang Suo) on a different occasion.  You can also read a more extensive biography of Rice written by Tze-jer Chuang and John Rudnicki.

For over four decades Rice has defined many of the most exciting frontiers of solid mechanics. It is worth reflecting on the enduring areas of research where the issues were framed and the key questions asked (and often answered) by Rice: nonlinear fracture mechanics, localization of deformation, growth and coalescence of voids, rate-dependent plasticity, ductile-to-brittle transition, interfacial facture, poroelasticity, frictional stability; the list goes on. A recent list of the 19 all-time most cited papers in solid and computational mechanics (http://imechanica.org/node/587) contained four papers directly related to Rice: the J-integral, the HRR field (with Rosengre), void growth (with Tracey), and the Gurson model (by Rice's PhD student Gurson). The ISI records 14,127 citations to his papers, with the h-index 59. (The ISI list is incomplete, missing his several most cited papers.) While these numbers are extremely large, they in fact significantly underestimate his influence, since his ideas are so embedded that reference to his ideas are often made without citation.

In the recent decade, Rice has focused on the mechanics of geological processes. The radically different time scales of the interseismic period (centuries to millennia) and the seismic event (tens to hundreds of seconds) present enormous computational challenges. Rice and Lapusta developed an ingenious separation of quasi-static and dynamic terms that enables efficient and accurate computation of the dynamic stressing effects. These models are the most accurate descriptions we have of earthquakes. As computational capabilities improve, it becomes feasible to model friction more closely resembling laboratory observations, and the Lapusta-Rice simulations become more and more "earthlike".

Rice has also made enormous contributions to our knowledge of dynamic rupture propagation. With Zheng and Perrin, he determined the conditions that promote self-healing slip pulses as opposed to a crack-like mode of rupture. He has also explored the implications of contrast in elastic properties across a fault. With Ranjith and Cochard, Rice clarified the nature of a remarkable dynamic instability on a bimaterial interface, and showed how to regularize the problem and deduced implications for several important processes. More recently, Rice and Rudnicki analyzed dynamic effects associated with a contrast of poroelastic properties. Rice and co-workers have explored the tendency of propagating earthquake ruptures to branch off the main fault onto adjoining structures. They have shown that the tendency for branching, and indeed the direction of the branch fault, depends on the orientation of the principal stresses relative to the fault and the speed of the rupture front. They have compared the model predictions with observations from among others the 1992 Landers rupture and the great Denali earthquake in Alaska. In both cases the model does a remarkably good job of predicting rupture behavior, and offers the possibility of predicting the response in future quakes.

In the last few years, Rice has made significant progress in understanding thermal effects of water-infiltrated rocks on faulting. Because the coefficient of thermal expansion of water greatly exceeds that of rock, heat generated by a slip increases the pressure in water. Rice analyzed the coupled flow of fluid and heat for a planar fault model with a fault slipping at a constant speed. Fault strength decreases with slip in a manner that can be described, for these special conditions, by nonlinear slip weakening. Rice showed that this leads to a slip-dependent fracture energy that is in remarkably good agreement with fracture energies inferred for earthquakes, both in absolute amplitude and in the slip dependence of fracture energy. While considerable uncertainties exist on both sides of the comparison, this represents as close to a field confirmation of theory as one can achieve without direct sampling of the fault during and earthquake. This is a tremendously exciting result and suggests a paradigm in which earthquake nucleation is governed by rate and state friction, while the physics of rapid slip is controlled by shear heating induced thermal pressurization.

Rice's work is marked by elegant mechanics, state-of-the-art computations, and penetrating interpretation of results within a broad context of laboratory and field observations. He is also an excellent communicator. He has been instrumental in showing the materials science and geophysics communities that careful, rigorous mechanics can address seemingly intractable problems in their disciplines.

Professor Rice is unique in solid mechanics in terms of the depth, breadth and impact of his contributions.