Finding Order in Chaos: Complexity in the Career of Don L Anderson

Don Anderson's career has been marked by a long standing interest in plate tectonics and the earth's interior. But from time to time, he has departed from these major themes to investigate related topics. For example, during the 1970's, he proposed several seminal ideas, such as the applicability of cracks and fracture theory to earthquakes, and the idea of accelerated plate tectonics. Although on the surface, these topics might seem quite disparate from mantle convection, seismic structure of the earth's interior, and thermodynamics of mineral phases, they nonetheless are now known to share common theoretical underpinnings. In particular, the concepts of nonlinear dynamical systems, complexity, chaos, and energy and fitness landscapes can be used to describe the evolution of all complex nonlinear systems. The principle of minimum free energy (maximum fitness) is frequently used to obtain Langevin-type equations for such systems, and ideas of statistical field theory are employed to obtain scaling exponents and other features. In this talk, we describe these ideas and relate them to the types of problems in which Don Anderson has been primarily interested.