Research Interests

I am an observational seismologist interested in both earthquakes and what seismic waves tell us about the inside of the Earth. Although I have enjoyed working on a diversity of projects, they usually share a common theme-the mining of large seismic data sets to learn new things about the Earth. In global seismology, I have studied upper-mantle discontinuity properties, scattering from small-scale structures, and seismic attenuation. In particular, I have applied stacking (averaging) methods to improve signal-to-noise ratios and make visible features in the waveforms that are not obvious on single records, such as weak reflections from mantle discontinuities. In southern California, my work has focused on improving micro-earthquake locations and focal mechanisms using robust methods and waveform cross-correlation. More recently, my colleagues and I have experimented with back-projection methods to image earthquake ruptures, such as the 2004 Sumatra-Andaman and Parkfield earthquakes. Stacking methods have also proven useful in performing comprehensive analyses of spectra from thousands of earthquakes to resolve stress drop and other source properties.

Membership Type


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Primary Section

Section 16: Geophysics

Secondary Section

Section 15: Geology