Overview

Plate tectonics, the surface manifestation of mantle convection, controls fundamental planetary processes, including most earthquakes, volcanoes, and mountain building; volatile exchange between the Earth’s solid and surface layers; and long-term changes in sea level. However, first-order questions about plate tectonics remain unresolved. What physical and chemical properties define the lithosphere and allow it to translate coherently over the asthenosphere? What are the processes that form and subsequently modify the lithosphere? What is the frequency-dependent response of the mantle to an applied stress (i.e., what is its rheology)? How and why have plate motions changed over time, and what are the consequences for sea level and climate?

My research addresses these questions through analyzing and interpreting seismic waves and other geophysical data. A theme that weaves through many of my projects is the integration of seismological results with data and theory from diverse fields of the geosciences, including rock and mineral physics, petrology, and geochemistry, in order to produce a more complete picture of the planet’s interior. My research can be loosely grouped into three general areas, recognizing that there is considerable overlap between them: (1) innovating new approaches for seismic imaging of the lithosphere and asthenosphere; (2) investigating the formation and evolution of oceanic lithosphere; and (3) inferring the rheology of the mantle from seismic data. A particular research focus is seismic-wave attenuation, and I have used a combination of computational simulations and observational analyses to develop new approaches for imaging attenuation variations in the mantle.

Brown Affiliations

• Earth, Environmental, and Planetary Sciences