I am interested in understanding the processes that assemble and occur in the bodies of silicic magma that give rise to huge, explosive eruptions that spread ash continent-wide. My students and I study young volcanoes to determine how large and how explosive future eruptions might be, how frequently they are likely to occur, and what mechanisms trigger eruptions. We also do field-based studies in mountainous areas where plutons and the guts of volcanoes are well-exposed, mapping them and then analyzing their products in the laboratory, in order to reconstruct the life histories of these systems. To these ends we make extension use of 40-39Ar geochronology and use the Stanford-USGS ion probe to determine U-Pb and U-series ages. The main foci of our current research are (1) widespread Mid-Miocene silicic volcanism and calderas associated with the Columbia River flood basalts; (2) controls on the pre-eruptive concentrations of energy-critical elements in silicic magmas as evidenced by melt inclusions; (3) petrologic evidence for volcanic hazards in the Long Valley--Mammoth Mountain--Mono Craters--Mono Basin region; and (4) volcanic hazards of western Saudi Arabia at Harrat Rahat and petrologic study of the origin of trachytes associated with young basaltic lavas. I also have an interest in geoarchaeology, especially in the application of petrologic and geochemical techniques to determining the provenance of obsidian and ceramics.
I teach an introductory physical geology course that culminates in a field trip to Death Valley and the eastern Sierra Nevada. My upper-division-level course on volcanology includes a field trip to young volcanism of the eastern Sierra Nevada (Long Valley, Mammoth Mountain, Mono Craters, Mono Lake). I teach a graduate-level course on igneous petrogenesis, and field seminars in physical volcanology of the southern Cascade arc and transform-related volcanism in the Coast Range of California, as well as specialized graduate seminars in petrology and physical volcanology from time to time.
Associate Vice Provost for Graduate Education (2006-07); Associate Dean for Graduate Policy (2005-06); Member, Faculty Steering Committee, Campaign for Undergraduate Education (2000-05); Member, Executive Committee, Interdisciplinary Program in Archaeology (2000-2008); Faculty leader, Stanford Alumni trip to Mongolia