What do you do?
I am basically a structural geologist with interests in the mechanisms of rock deformation, the structures developed in rocks that are characteristic of the operation of those mechanisms, how we can interpret those structures, and the rheologic properties that we can infer from the evidence for the operation of those mechanisms. At present my principal interest is in the brittle deformation of crustal rocks, especially during faulting. We use seismic data from earthquakes as well as field data from shear zones to tell us how the crust has deformed during faulting events, and the seismic data gives us a three-dimensional view of how the deformation in distributed in the crust.

Why should the general public be interested in what you do?
All geologists, I would hazard to say, are driven by a curiosity about how the Earth works, what its history is, and what is going to happen to it. These questions are relevant to everyone who cares about our home in space. My particular research is oriented toward understanding the deformation processes that are associated with earthquakes. The work of our group provides a means to improve our assessment of seismic hazard in seismically active or potentially active areas. We aim to advance our fundamental understanding of crustal deformation, its relation to seismicity and to tectonic motions, and of the use seismic data to improve our understanding of how the earth deforms.

Why does it interest you?
I am fascinated by the questions of how and why deformation occurs in the earth. Investigating those processes involves understanding the detailed mechanisms by which rock deformation occurs, understanding how evidence for those mechanisms is recorded in deformed rocks, and then using that understanding to work backwards from field or geophysical data to infer the distribution of deformation and the rheologic characteristics of the rocks when they were deforming. It is a fascinating puzzle that requires interdisciplinary work in fields including materials science, continuum mechanics, geophysics, and structural geology, and integrating these fields provides an exciting and stimulating opportunity for new advances.

What major advances/discoveries have occurred in your research field over the last 10 years?
The research by our group has provided insight into the geometry and distribution of strain, both horizontally and with depth that is associated with major earthquakes as well as in regions of distributed seismicity. It has provided new insights into the tectonics of regions such as the San Francisco Bay area and the Northern California Coast Range. We also have discovered that fault block rotations have an observable effect on the seismic signals, which had not been recognized before, and we have proposed a physical mechanism that accounts for this effect.