Ph.D. Candidate in Geophysics
California Institute of Technology
358 South Mudd
1200 E. California Blvd.
Pasadena, CA 91125
efwillia (at) gps.caltech.edu
I am a Ph.D. candidate in geophysics at the Caltech Seismo Lab, working with Prof. Zhongwen Zhan. In my research, I develop diverse applications of ambient noise in engineering and environmental seismology.
Much of my recent work involves distributed acoustic sensing (DAS), an emerging technology that converts ordinary fiber-optic cables into dense arrays of broadband strainmeters. In urban Pasadena, I am working with a multi-year continuous DAS recording on a 37-km fiber seismic network to map shallow shear-wave velocity structure and monitor velocity changes as a proxy for subsurface hydrologic conditions. With ocean-bottom DAS recordings from offshore Belgium and Spain, I am extending the techniques of seismic interferometry to ocean surface gravity waves in order to measure spatio-temporal variations in current speed and sea state. Other projects include wind turbine localization from passive ocean-bottom recordings, long-term structural health monitoring of Caltech's Millikan Library with ambient vibrations, and investigating the physics of microseism geneneration with ocean-bottom DAS data.