ABSTRACT

One of the dreams of geoscience is to connect deep structures to surface processes. To do this, one must understand the forces driving, and the strengths resisting, deformation. Since these forces and strengths are primarily driven by density, temperature, and composition (including volatiles), it becomes imperative to move from seismological maps of red and blue regions to maps of physical state. However, a range of phenomena can produce similar observations; for instance, melting and temperature increases can both produce similar changes in seismic velocities. Hence, a range of observeables must be combined--carefully--to properly assess the range of physical state variations that fit the data. In this talk, some of the challenges in assessing physical state will be considered, and several examples of integrating knowledge to assess physical state will be demonstrated.