AGU member since 1982 (Fellow, 1999). Professor of geophysics, Scripps Institution of Oceanography, University of California, San Diego (UCSD). Major research interests include upper-mantle discontinuities, deep-Earth scattering, earthquake location methods, and spectral analysis for Q and source properties. B.S., 1978, Yale University; Ph.D., 1986, Scripps Institution of Oceanography, University of California, San Diego. Postdoc at University of Cambridge, 1986–1988; Green scholar/assistant researcher at UCSD, 1988–1991; on UCSD faculty from 1991. Member, Seismological Society of America; IRIS Executive Committee, 1996–2000; USArray Steering Committee, 1998–2002; SCEC Seismology Committee, 2001–2006; NSF Geophysics Panel, 2007–2009. Authored 110 refereed papers, 55 in AGU publications. AGU Fall Meeting Program Committee, 1998–2000; AGU Gutenberg Lecturer, 2005.