Bill Evans, PhD
My research focused on volcanic volatiles and water-rock interaction in geothermal systems.
Gases are an important factor in volcanic hazards because of their role in driving explosive eruptions and their intrinsic toxicity. Part of the answer to, “What could happen?” at a restless volcano comes from gas studies. The mechanism of gas generation at depth and gas migration up through boiling hydrothermal systems, cold groundwaters, and the unsaturated zone are all complex processes that are only partly understood. The goal of my research is to use gas flux, composition, and isotope values to refine our general understanding of these processes and to apply this information to studies that focus on the behavior and hazards of individual volcanoes. The research involved identifying the areas of highest interest, planning the field investigations, determining the most appropriate sampling protocol, analyzing for the bulk composition and isotopic characteristics of the gas, and interpreting and publishing the results.
Science and Products
Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA
A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California
Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing
Boiling water at Hot Creek— The dangerous and dynamic thermal springs in California’s Long Valley Caldera
Mantle and Crustal Sources of Carbon, Nitrogen, and Noble gases in Cascade-Range and Aleutian-Arc Volcanic gases
Report of hydrologic investigations in the Three Sisters area of central Oregon, Summer 2001
Invisible CO2 gas killing trees at Mammoth Mountain, California
Hydrothermal activity and carbon-dioxide discharge at Shrub and upper Klawasi mud volcanoes, Wrangell Mountains, Alaska
Geochemistry and hydromechanical interactions of fluids associated with the San Andreas fault system, California
Invisible CO2 gas killing trees at Mammoth Mountain, California
Non-USGS Publications**
**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
Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA
A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California
Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing
Boiling water at Hot Creek— The dangerous and dynamic thermal springs in California’s Long Valley Caldera
Mantle and Crustal Sources of Carbon, Nitrogen, and Noble gases in Cascade-Range and Aleutian-Arc Volcanic gases
Report of hydrologic investigations in the Three Sisters area of central Oregon, Summer 2001
Invisible CO2 gas killing trees at Mammoth Mountain, California
Hydrothermal activity and carbon-dioxide discharge at Shrub and upper Klawasi mud volcanoes, Wrangell Mountains, Alaska
Geochemistry and hydromechanical interactions of fluids associated with the San Andreas fault system, California
Invisible CO2 gas killing trees at Mammoth Mountain, California
Non-USGS Publications**
**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.