Fault rupture in the Napa area caused extensive damage, and fault afterslip is confounding repair work by residents. FEMA commissioned USGS to forecast the afterslip; a challenging task never done for any other earthquake. The USGS used a variety of field observations including alinement array and GPS surveys, InSAR and UAVSAR data to develop a new quantitative system for characterizing fault afterslip hazard.

Dr. Ken Hudnut is a Geophysicist for the Earthquake Science Center of the United States Geological Survey (since 1992) and a Visiting Associate in Geophysics on the faculty of the California Institute of Technology in Pasadena, California. He recently led the fault afterslip forecast for the South Napa earthquake for FEMA. To better understand earthquakes and faults, he incorporates real-time GPS into the ShakeAlert earthquake early warning system for the west coast of the US, and innovator of systems for airborne imagery of active faults. From 2009-2012, he coordinated all USGS Earthquake Program work in Southern California and served as chair of the statewide California Integrated Seismic Network. He has served multiple terms on the boards of the Southern California Earthquake Center and UNAVCO. He recently conducted field studies after the earthquakes in Haiti and Baja California, Mexico and provided expertise to investigate damaging earthquakes in China. He led the earthquake source design for the ShakeOut scenario, a M 7.8 on the southern San Andreas Fault, and has directly advised the Governor of California on the 'Big One' and the statewide earthquake threat. He received his Ph.D. (in Geology) from Columbia in 1989, and his A.B. (high honors in Earth Sciences) from Dartmouth in 1983.