Bill Evans, PhD (Former Employee)
Science and Products
Chemical and isotopic compositions of gases from volcanic and geothermal areas in California Chemical and isotopic compositions of gases from volcanic and geothermal areas in California
Gas chemical and isotopic compositions are reported for samples collected from 9 volcanic and geothermal areas in California: Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Mono Lake Volcanic Field, Long Valley Caldera, Mammoth Mountain, Coso Volcanic Field, and Salton Sea Geothermal Field. Beginning in 2014, gas samples were collected as part of...
Chemical and isotopic data on gases and waters for thermal and non-thermal features across Yellowstone National Park (2003-2015) Chemical and isotopic data on gases and waters for thermal and non-thermal features across Yellowstone National Park (2003-2015)
Degassing thermal features at Yellowstone National Park include spectacular geysers, roiling hot springs, bubbling mud pots, fumaroles, frying pans, and areas of passive degassing characterized by steaming ground. Most of these features are readily identified by visible clouds of steam that are occasionally accompanied by a strong rotten egg odor from emissions of hydrogen sulfide gas...
Fumarole gas geochemistry and tree-ring radiocarbon data at Mammoth Mountain, California (1989-2016) Fumarole gas geochemistry and tree-ring radiocarbon data at Mammoth Mountain, California (1989-2016)
Mammoth Mountain is a dacitic dome complex located on the southwestern rim of Long Valley Caldera, California. Mammoth Mountain has exhibited unrest over the past ~30 years, characterized by seismicity over a broad range of depths, elevated 3He/4He ratios in fumarolic gas and large-scale diffuse CO2 emissions. Monitoring of this unrest has included collection of fumarole gas samples for
Filter Total Items: 110
Geochemistry and fluxes of gases from hydrothermal features at Newberry Volcano, Oregon, USA Geochemistry and fluxes of gases from hydrothermal features at Newberry Volcano, Oregon, USA
We present the chemical and isotopic compositions of gases and fluxes of CO2 from the hydrothermal features of Newberry Volcano, a large composite volcano located in Oregon's Cascade Range with a summit caldera that hosts two lakes, Paulina and East Lakes. Gas samples were collected from 1982 to 2021 from Paulina Hot Springs (PHS) on the shore of Paulina Lake, East Lake Hot Springs (ELHS...
Authors
Jennifer L. Lewicki, William C. Evans, Steven E. Ingebritsen, Laura E. Clor, Peter J. Kelly, Sara Peek, Robert A. Jensen, Andrew G. Hunt
Groundwater dynamics at Kīlauea Volcano and vicinity, Hawaiʻi Groundwater dynamics at Kīlauea Volcano and vicinity, Hawaiʻi
Kīlauea Volcano, on the Island of Hawaiʻi, is surrounded and permeated by active groundwater systems that interact dynamically with the volcanic system. A generalized conceptual model of Hawaiian hydrogeology includes high-level dike-impounded groundwater, very permeable perched and basal aquifers, and a transition (mixing) zone between freshwater and saltwater. Most high-level...
Authors
Shaul Hurwitz, Sara E. Peek, Martha A. Scholl, Deborah Bergfeld, William C. Evans, James P. Kauahikaua, Stephen B. Gingerich, Paul A. Hsieh, R. Lopaka Lee, Edward F. Younger, Steven E. Ingebritsen
A post-eruption study of gases and thermal waters at Okmok Volcano, Alaska A post-eruption study of gases and thermal waters at Okmok Volcano, Alaska
We report here on the first focused study of gas discharges and thermal spring waters at Okmok Volcano since the 2008 phreatomagmatic eruptions. Results include the first compositional gas data from Okmok with minimal air contamination and the first data on magmatic carbon in Okmok spring waters. Chemical and isotopic analyses of the waters and gases are used to assess the character of...
Authors
Deborah Bergfeld, William C. Evans, Andrew G. Hunt, Taryn Lopez, Janet Schaefer
Potential for increased hydrothermal arsenic flux during volcanic unrest: Implications for California water supply Potential for increased hydrothermal arsenic flux during volcanic unrest: Implications for California water supply
The hydrothermal systems associated with the restless high-threat volcanoes at Lassen and Long Valley, California, each release large amounts of arsenic (As) to surface waters – ~6 and ~8 metric tons/yr, respectively. The hydrothermal As output can increase during volcanic unrest, as illustrated by a two-fold increase during unrest at Lassen in 2014–15. During that period of unrest...
Authors
Steven E. Ingebritsen, William C. Evans
Hydraulic, geochemical, and thermal monitoring of an aquifer system in the vicinity of Mammoth Lakes, Mono County, California, 2015–17 Hydraulic, geochemical, and thermal monitoring of an aquifer system in the vicinity of Mammoth Lakes, Mono County, California, 2015–17
Since 2014, the U.S. Geological Survey has been working in cooperation with the Bureau of Land Management, Mono County, Ormat Technologies, Inc., and the Mammoth Community Water District to design and implement a groundwater-monitoring program for the proposed Casa Diablo IV Geothermal Power Project in Long Valley Caldera, California, to characterize baseline groundwater-level, water...
Authors
James F. Howle, William C. Evans, Devin L. Galloway, Paul A. Hsieh, Shaul Hurwitz, Gregory A. Smith, Joseph Nawikas
Rate of magma supply beneath Mammoth Mountain, California based on helium isotopes and CO2 emissions Rate of magma supply beneath Mammoth Mountain, California based on helium isotopes and CO2 emissions
Mammoth Mountain, California, has exhibited unrest over the past ~30 years, characterized by seismicity over a broad range of depths, elevated 3He/4He ratios in fumarolic gas, and large-scale diffuse CO2 emissions. This activity has been attributed to magmatic intrusion, but minimal ground deformation and the presence of a shallow crustal gas reservoir beneath Mammoth Mountain pose a...
Authors
Jennifer L. Lewicki, William C. Evans, Emily K. Montgomery-Brown, Margaret T. Mangan, John King, Andrew G. Hunt
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
Chemical and isotopic compositions of gases from volcanic and geothermal areas in California Chemical and isotopic compositions of gases from volcanic and geothermal areas in California
Gas chemical and isotopic compositions are reported for samples collected from 9 volcanic and geothermal areas in California: Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Mono Lake Volcanic Field, Long Valley Caldera, Mammoth Mountain, Coso Volcanic Field, and Salton Sea Geothermal Field. Beginning in 2014, gas samples were collected as part of...
Chemical and isotopic data on gases and waters for thermal and non-thermal features across Yellowstone National Park (2003-2015) Chemical and isotopic data on gases and waters for thermal and non-thermal features across Yellowstone National Park (2003-2015)
Degassing thermal features at Yellowstone National Park include spectacular geysers, roiling hot springs, bubbling mud pots, fumaroles, frying pans, and areas of passive degassing characterized by steaming ground. Most of these features are readily identified by visible clouds of steam that are occasionally accompanied by a strong rotten egg odor from emissions of hydrogen sulfide gas...
Fumarole gas geochemistry and tree-ring radiocarbon data at Mammoth Mountain, California (1989-2016) Fumarole gas geochemistry and tree-ring radiocarbon data at Mammoth Mountain, California (1989-2016)
Mammoth Mountain is a dacitic dome complex located on the southwestern rim of Long Valley Caldera, California. Mammoth Mountain has exhibited unrest over the past ~30 years, characterized by seismicity over a broad range of depths, elevated 3He/4He ratios in fumarolic gas and large-scale diffuse CO2 emissions. Monitoring of this unrest has included collection of fumarole gas samples for
Filter Total Items: 110
Geochemistry and fluxes of gases from hydrothermal features at Newberry Volcano, Oregon, USA Geochemistry and fluxes of gases from hydrothermal features at Newberry Volcano, Oregon, USA
We present the chemical and isotopic compositions of gases and fluxes of CO2 from the hydrothermal features of Newberry Volcano, a large composite volcano located in Oregon's Cascade Range with a summit caldera that hosts two lakes, Paulina and East Lakes. Gas samples were collected from 1982 to 2021 from Paulina Hot Springs (PHS) on the shore of Paulina Lake, East Lake Hot Springs (ELHS...
Authors
Jennifer L. Lewicki, William C. Evans, Steven E. Ingebritsen, Laura E. Clor, Peter J. Kelly, Sara Peek, Robert A. Jensen, Andrew G. Hunt
Groundwater dynamics at Kīlauea Volcano and vicinity, Hawaiʻi Groundwater dynamics at Kīlauea Volcano and vicinity, Hawaiʻi
Kīlauea Volcano, on the Island of Hawaiʻi, is surrounded and permeated by active groundwater systems that interact dynamically with the volcanic system. A generalized conceptual model of Hawaiian hydrogeology includes high-level dike-impounded groundwater, very permeable perched and basal aquifers, and a transition (mixing) zone between freshwater and saltwater. Most high-level...
Authors
Shaul Hurwitz, Sara E. Peek, Martha A. Scholl, Deborah Bergfeld, William C. Evans, James P. Kauahikaua, Stephen B. Gingerich, Paul A. Hsieh, R. Lopaka Lee, Edward F. Younger, Steven E. Ingebritsen
A post-eruption study of gases and thermal waters at Okmok Volcano, Alaska A post-eruption study of gases and thermal waters at Okmok Volcano, Alaska
We report here on the first focused study of gas discharges and thermal spring waters at Okmok Volcano since the 2008 phreatomagmatic eruptions. Results include the first compositional gas data from Okmok with minimal air contamination and the first data on magmatic carbon in Okmok spring waters. Chemical and isotopic analyses of the waters and gases are used to assess the character of...
Authors
Deborah Bergfeld, William C. Evans, Andrew G. Hunt, Taryn Lopez, Janet Schaefer
Potential for increased hydrothermal arsenic flux during volcanic unrest: Implications for California water supply Potential for increased hydrothermal arsenic flux during volcanic unrest: Implications for California water supply
The hydrothermal systems associated with the restless high-threat volcanoes at Lassen and Long Valley, California, each release large amounts of arsenic (As) to surface waters – ~6 and ~8 metric tons/yr, respectively. The hydrothermal As output can increase during volcanic unrest, as illustrated by a two-fold increase during unrest at Lassen in 2014–15. During that period of unrest...
Authors
Steven E. Ingebritsen, William C. Evans
Hydraulic, geochemical, and thermal monitoring of an aquifer system in the vicinity of Mammoth Lakes, Mono County, California, 2015–17 Hydraulic, geochemical, and thermal monitoring of an aquifer system in the vicinity of Mammoth Lakes, Mono County, California, 2015–17
Since 2014, the U.S. Geological Survey has been working in cooperation with the Bureau of Land Management, Mono County, Ormat Technologies, Inc., and the Mammoth Community Water District to design and implement a groundwater-monitoring program for the proposed Casa Diablo IV Geothermal Power Project in Long Valley Caldera, California, to characterize baseline groundwater-level, water...
Authors
James F. Howle, William C. Evans, Devin L. Galloway, Paul A. Hsieh, Shaul Hurwitz, Gregory A. Smith, Joseph Nawikas
Rate of magma supply beneath Mammoth Mountain, California based on helium isotopes and CO2 emissions Rate of magma supply beneath Mammoth Mountain, California based on helium isotopes and CO2 emissions
Mammoth Mountain, California, has exhibited unrest over the past ~30 years, characterized by seismicity over a broad range of depths, elevated 3He/4He ratios in fumarolic gas, and large-scale diffuse CO2 emissions. This activity has been attributed to magmatic intrusion, but minimal ground deformation and the presence of a shallow crustal gas reservoir beneath Mammoth Mountain pose a...
Authors
Jennifer L. Lewicki, William C. Evans, Emily K. Montgomery-Brown, Margaret T. Mangan, John King, Andrew G. Hunt
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.