I am currently a Research Geologist at the USGS California Volcano Observatory (CalVO) and fundamentally a field geologist who maps Cascade volcanoes and interprets their eruptive history, geochemistry and petrology.
My primary interests are in using mineralogy, crystal chemistry and rock textures to determine the origin and evolution of magmas erupting at Cascade volcanoes. I am currently the USGS geologist who most versed in geology of the Lassen Volcanic Center and southernmost Cascades volcanoes and the geology of Mount St. Helens. I interface with managers and staff at Lassen Volcanic National Park and Mount St. Helens National Volcanic Monument on geologic and interpretation issues in those parks. I entered the USGS as a student field assistant in 1975 and have been employed there ever since.
I am currently in the final stages of producing a geologic map of Mount St. Helens. The field work is complete and I am writing the materials that will accompany the map. My goal is to understand the complex eruptive history of Mount St. Helens as thoroughly as possible using stratigraphy and geochronology. I and colleagues have added considerable detail to the geologic history framework produced by earlier USGS geologists.
My work at Lassen is at a mature stage. The geologic map of the Lassen Volcanic Center and vicinity describes the geology and eruptive history of the Lassen Volcanic Center and the many smaller volcanoes that surround it. The basic geologic work at Lassen has been used to provide a framework for interpretation of the hydrothermal system and as basis for volcano hazards assessment of the region. A variety of topical studies in collaboration with colleagues include geochronology, geochemistry, isotope geology, petrology, mineral chemistry, physical volcanology, geophysics, tectonics and hydrothermal systems. Some of the geologic processes described at Lassen have guided work at other Cascades volcanoes and the arc as a whole.
Former associate editor Bulletin of Volcanology
Education and Certifications
Ph.D. University of California-Santa Cruz, 1993
M.S. California State California-San Jose, 1983
B.S. University of California-Santa Cruz, 1976
Affiliations and Memberships*
Geological Society of America
American Geophysical Union
Honors and Awards
Geological Society of America Fellow
Science and Products
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government