Bill Evans, PhD (Former Employee)
Science and Products
Filter Total Items: 110
Long-term changes in quiescent degassing at Mount Baker Volcano, Washington, USA; Evidence for a stalled intrusion in 1975 and connection to a deep magma source Long-term changes in quiescent degassing at Mount Baker Volcano, Washington, USA; Evidence for a stalled intrusion in 1975 and connection to a deep magma source
Long-term changes have occurred in the chemistry, isotopic ratios, and emission rates of gas at Mount Baker volcano following a major thermal perturbation in 1975. In mid-1975 a large pulse in sulfur and carbon dioxide output was observed both in emission rates and in fumarole samples. Emission rates of CO2 and H2S were ∼ 950 and 112 t/d, respectively, in 1975; these decreased to ∼ 150...
Authors
Cynthia A. Werner, William C. Evans, Michael P. Poland, Michael P. Doukas, D.S. Tucker
Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring
Diffuse CO2 efflux near the Ukinrek Maars, two small volcanic craters that formed in 1977 in a remote part of the Alaska Peninsula, was investigated using accumulation chamber measurements. High CO2 efflux, in many places exceeding 1000 g m−2 d−1, was found in conspicuous zones of plant damage or kill that cover 30,000–50,000 m2 in area. Total diffuse CO2 emission was estimated at 21–44...
Authors
William C. Evans, D. Bergfeld, R. G. McGimsey, A.G. Hunt
Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA
A spatial survey of the chemical and isotopic composition of fluids from the Long Valley hydrothermal system was conducted. Starting at the presumed hydrothermal upwelling zone in the west moat of the caldera, samples were collected from the Casa Diablo geothermal field and a series of monitoring wells defining a nearly linear, ~14 km long, west-to-east trend along the proposed fluid...
Authors
Shaun T. Brown, B. Mack Kennedy, Donald J. DePaolo, William C. Evans
A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California
In August 2004, a National Forest fire crew extinguished a 1.2 ha fire in a wilderness area ~40 km northeast of Santa Barbara, California. Examination revealed that the fire originated on a landslide dotted with superheated fumaroles. A 4 m borehole punched near the hottest (262 °C) fumarole had a maximum temperature of 307 °C. Temperatures in this borehole have been decreasing by ~0.1...
Authors
Robert H. Mariner, Scott A. Minor, A. King, J.R. Boles, Karl S. Kellogg, William C. Evans, Gary Landis, A.G. Hunt, Christy B. Till
Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing
Evolution of CO2 in Lakes Monoun and Nyos (Cameroon) before and during controlled degassing is described using results of regular monitoring obtained during the last 21 years. The CO2(aq) profiles soon after the limnic eruptions were estimated for Lakes Monoun and Nyos using the CTD data obtained in October and November 1986, respectively. Based on the CO2(aq)profiles through time, the...
Authors
M. Kusakabe, T. Ohba, Issa, Y. Yoshida, H. Satake, T. Ohizumi, William C. Evans, G. Tanyileke, G.W. Kling
The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results
A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8??106 m3 of sulfurous, clay-rich debris and acidic water, with an...
Authors
J.R. Schaefer, W. E. Scott, William C. Evans, J. Jorgenson, R. G. McGimsey, B. Wang
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
Filter Total Items: 110
Long-term changes in quiescent degassing at Mount Baker Volcano, Washington, USA; Evidence for a stalled intrusion in 1975 and connection to a deep magma source Long-term changes in quiescent degassing at Mount Baker Volcano, Washington, USA; Evidence for a stalled intrusion in 1975 and connection to a deep magma source
Long-term changes have occurred in the chemistry, isotopic ratios, and emission rates of gas at Mount Baker volcano following a major thermal perturbation in 1975. In mid-1975 a large pulse in sulfur and carbon dioxide output was observed both in emission rates and in fumarole samples. Emission rates of CO2 and H2S were ∼ 950 and 112 t/d, respectively, in 1975; these decreased to ∼ 150...
Authors
Cynthia A. Werner, William C. Evans, Michael P. Poland, Michael P. Doukas, D.S. Tucker
Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring
Diffuse CO2 efflux near the Ukinrek Maars, two small volcanic craters that formed in 1977 in a remote part of the Alaska Peninsula, was investigated using accumulation chamber measurements. High CO2 efflux, in many places exceeding 1000 g m−2 d−1, was found in conspicuous zones of plant damage or kill that cover 30,000–50,000 m2 in area. Total diffuse CO2 emission was estimated at 21–44...
Authors
William C. Evans, D. Bergfeld, R. G. McGimsey, A.G. Hunt
Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA
A spatial survey of the chemical and isotopic composition of fluids from the Long Valley hydrothermal system was conducted. Starting at the presumed hydrothermal upwelling zone in the west moat of the caldera, samples were collected from the Casa Diablo geothermal field and a series of monitoring wells defining a nearly linear, ~14 km long, west-to-east trend along the proposed fluid...
Authors
Shaun T. Brown, B. Mack Kennedy, Donald J. DePaolo, William C. Evans
A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California
In August 2004, a National Forest fire crew extinguished a 1.2 ha fire in a wilderness area ~40 km northeast of Santa Barbara, California. Examination revealed that the fire originated on a landslide dotted with superheated fumaroles. A 4 m borehole punched near the hottest (262 °C) fumarole had a maximum temperature of 307 °C. Temperatures in this borehole have been decreasing by ~0.1...
Authors
Robert H. Mariner, Scott A. Minor, A. King, J.R. Boles, Karl S. Kellogg, William C. Evans, Gary Landis, A.G. Hunt, Christy B. Till
Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing Evolution of CO2 in Lakes Monoun and Nyos, Cameroon, before and during controlled degassing
Evolution of CO2 in Lakes Monoun and Nyos (Cameroon) before and during controlled degassing is described using results of regular monitoring obtained during the last 21 years. The CO2(aq) profiles soon after the limnic eruptions were estimated for Lakes Monoun and Nyos using the CTD data obtained in October and November 1986, respectively. Based on the CO2(aq)profiles through time, the...
Authors
M. Kusakabe, T. Ohba, Issa, Y. Yoshida, H. Satake, T. Ohizumi, William C. Evans, G. Tanyileke, G.W. Kling
The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results
A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8??106 m3 of sulfurous, clay-rich debris and acidic water, with an...
Authors
J.R. Schaefer, W. E. Scott, William C. Evans, J. Jorgenson, R. G. McGimsey, B. Wang
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.