Seismologist and geophysicist Paul Gordon Silver, at Terrestrial Magnetism, died in an automobile accident in North Carolina on August 7, 2009, as he was driving his daughter Celine back from a research internship in Florida. Celine perished in the crash as well.

A member of the Research Staff at the Carnegie Institution’s Department of Terrestrial Magnetism in northwest Washington, D.C., since 1982, Silver was an international leader in understanding how earthquakes are triggered and how they interact with each other. Born in Los Angeles, Silver obtained a B.A. degree in psychology from UCLA, a B.A. in geology from UC Berkeley, and a Ph.D. in geophysics from UC San Diego in 1982. Since 1986 he has held a joint appointment as a Research Associate Professor at The Johns Hopkins University Department of Earth and Planetary Sciences.

Silver made a series of important contributions to earthquake research by observing the slow redistribution of stress and strain in the Earth. In one long-term study of small earthquakes triggered by a large event in southern California, he and his colleagues discovered an annual cycle: fall had the greatest number of earthquakes, spring the least. The team found that this pattern could be related to barometric pressure changes—less pressure meant reduced stress on the faults, which permitted them to move more frequently.

Just last year, Silver was co-author of a paper showing there were subtle changes in the speed of seismic waves that preceded two small earthquakes—encouraging results for the field of earthquake prediction.

Silver’s research took him all over the world. He organized and conducted seismic field experiments in northern Canada, southern Africa, Chile and Bolivia, China, and Tibet, as well in California and elsewhere in western North America. He is widely recognized for developing the techniques to determine the direction-dependence of seismic wave speeds in the Earth’s upper mantle, a procedure now in widespread use to study the patterns of convective flow in the Earth’s interior and the processes by which the continents were assembled.

Silver served as the President of the Seismology Section of the American Geophysical Union from 2004 to 2006, and he chaired the Board of Directors of both UNAVCO and the Incorporated Research Institutions for Seismology. He was a leader in proposing the concept of a Plate Boundary Observatory of seismometers, strainmeters, and geodetic instruments in western North America, a facility that is now operational as part of the EarthScope project of the National Science Foundation.

Among his honors, Silver was elected a Fellow of the American Academy of Arts and Sciences in 2007, and he was the Royal Astronomical Society Harold Jeffreys Lecturer in 2005. He was also a Fellow of the American Geophysical Union and the Geological Society of America and a member of Phi Beta Kappa.

A man of exceptional creativity and consistently good humor, Silver served as mentor and collaborator to younger scientists throughout his career. Many of the students and postdoctoral scientists who worked with Silver while at the Carnegie Institution continued to collaborate with him for years thereafter, testimony to the positive influence that he had on the careers of many now active in Earth science.

"Paul will be greatly missed. He was an exceptional scientist and a wonderful person," commented Carnegie president, Richard Meserve.

A skilled jazz musician, Silver was a drummer in a jazz trio that played throughout greater Washington, D.C.He is survived by his wife, Nathalie Valette-Silver of North Bethesda, his daughter, Karen Silver of Baltimore, and two sisters, Lauren Silver of Indianola, Washington, and Ellen Silver of Santa Rosa, California.

Donations can be sent to the Paul G. Silver Postdoctoral Fellowship in Seismology at Carnegie and to Taglit Birthright Israel

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Earth/Planetary Science