Todd Hoefen
Todd Hoefen is a Geophysicist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 113
Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates
An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic...
Authors
R.E. Wolf, S.A. Morman, P. L. Hageman, T.M. Hoefen, G.S. Plumlee
The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA
Mining operations began at a world-class vermiculite deposit at Vermiculite Mountain near Libby, Montana, circa 1920 and ended in 1990. Fibrous and asbestiform amphiboles intergrown with vermiculite ore are suspected to be a causative factor in an abnormally high number of cases of respiratory diseases in former mine and mill workers, and in residents of Libby. The question addressed in...
Authors
William H. Langer, Bradley S. Van Gosen, Gregory P. Meeker, David T. Adams, Todd M. Hoefen
Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes
In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for...
Authors
Ruth E. Wolf, Todd M. Hoefen, Philip L. Hageman, Suzette A. Morman, Geoffrey S. Plumlee
Detection and mapping of hydrocarbon deposits on Titan Detection and mapping of hydrocarbon deposits on Titan
We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH4), and clouds of hydrogen cyanide (HCN) aerosols using diagnostic spectral features...
Authors
Roger N. Clark, J. M. Curchin, Jason W. Barnes, Ralf Jaumann, Laurence A. Soderblom, Dale P. Cruikshank, Robert H. Brown, Sebastien Rodriguez, Jonathan Lunine, Katrin Stephan, Todd M. Hoefen, Stephane Le Mouelic, Christophe Sotin, Kevin H. Baines, Bonnie J. Buratti, Philip D. Nicholson
A method for quantitative mapping of thick oil spills using imaging spectroscopy A method for quantitative mapping of thick oil spills using imaging spectroscopy
In response to the Deepwater Horizon oil spill in the Gulf of Mexico, a method of near-infrared imaging spectroscopic analysis was developed to map the locations of thick oil floating on water. Specifically, this method can be used to derive, in each image pixel, the oil-to-water ratio in oil emulsions, the sub-pixel areal fraction, and its thicknesses and volume within the limits of...
Authors
Roger N. Clark, Gregg A. Swayze, Ira Leifer, K. Eric Livo, Raymond F. Kokaly, Todd Hoefen, Sarah Lundeen, Michael Eastwood, Robert O. Green, Neil Pearson, Charles Sarture, Ian McCubbin, Dar Roberts, Eliza Bradley, Denis Steele, Thomas Ryan, Roseanne Dominguez
A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data
This report describes a method to create color-composite images indicative of thick oil:water emulsions on the surface of clear, deep ocean water by using normalized difference ratios derived from remotely sensed data collected by an imaging spectrometer. The spectral bands used in the normalized difference ratios are located in wavelength regions where the spectra of thick oil:water...
Authors
Raymond F. Kokaly, Todd M. Hoefen, K. Eric Livo, Gregg A. Swayze, Ira Leifer, Ian B. McCubbin, Michael L. Eastwood, Robert O. Green, Sarah R. Lundeen, Charles M. Sarture, Denis Steele, Thomas Ryan, Eliza S. Bradley, Dar A. Roberts
Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team
All of the calculations and results in this report are preliminary and intended for the purpose, and only for the purpose, of aiding the incident team in assessing the extent of the spilled oil for ongoing response efforts. Other applications of this report are not authorized and are not considered valid. Because of time constraints and limitations of data available to the experts, many...
Authors
Victor F. Labson, Roger N. Clark, Gregg A. Swayze, Todd M. Hoefen, Raymond F. Kokaly, K. Eric Livo, Michael H. Powers, Geoffrey S. Plumlee, Gregory P. Meeker
A method for qualitative mapping of thick oil spills using imaging spectroscopy A method for qualitative mapping of thick oil spills using imaging spectroscopy
A method is described to create qualitative images of thick oil in oil spills on water using near-infrared imaging spectroscopy data. The method uses simple 'three-point-band depths' computed for each pixel in an imaging spectrometer image cube using the organic absorption features due to chemical bonds in aliphatic hydrocarbons at 1.2, 1.7, and 2.3 microns. The method is not...
Authors
Roger N. Clark, Gregg A. Swayze, Ira Leifer, K. Eric Livo, Sarah Lundeen, Michael Eastwood, Robert O. Green, Raymond F. Kokaly, Todd Hoefen, Charles Sarture, Ian McCubbin, Dar Roberts, Denis Steele, Thomas Ryan, Roseanne Dominguez, Neil Pearson
Examination of Libby, Montana, Fill Material for Background Levels of Amphibole from the Rainy Creek Complex Using Scanning Electron Microscopy and X-Ray Microanalysis Examination of Libby, Montana, Fill Material for Background Levels of Amphibole from the Rainy Creek Complex Using Scanning Electron Microscopy and X-Ray Microanalysis
Natural background levels of Libby-type amphibole in the sediment of the Libby valley in Montana have not, up to this point, been determined. The purpose of this report is to provide the preliminary findings of a study designed by both the U.S. Geological Survey and the U.S. Environmental Protection Agency and performed by the U.S. Geological Survey. The study worked to constrain the...
Authors
David T. Adams, William H. Langer, Todd M. Hoefen, Bradley S. Van Gosen, Gregory P. Meeker
Sample collection of ash and burned soils from the October 2007 southern California Wildfires Sample collection of ash and burned soils from the October 2007 southern California Wildfires
Between November 2 through 9, 2007 scientists from the U.S. Geological Survey (USGS) collected samples of ash and burned soils from 28 sites in six areas burned as a result of the Southern California wildfires of October 2007, including the Harris, Witch, Santiago, Ammo, Canyon, and Grass Valley Fires. The primary goal of this sampling and analysis effort was to understand how...
Authors
Todd M. Hoefen, Raymond F. Kokaly, Deborah A. Martin, Carlton J. Rochester, Geoffrey S. Plumlee, Greg Mendez, Eric G. Reichard, Robert N. Fisher
Environmental mapping of the World Trade Center area with imaging spectroscopy after the September 11, 2001 attack Environmental mapping of the World Trade Center area with imaging spectroscopy after the September 11, 2001 attack
The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) was flown over the World Trade Center area on September 16, 18, 22, and 23, 2001. The data were used to map the WTC debris plume and its contents, including the spectral signatures of asbestiform minerals. Samples were collected and used as ground truth for the AVARIS mapping. A number of thermal hot spots were observed with...
Authors
Roger N. Clark, Gregg A. Swayze, Todd M. Hoefen, Robert O. Green, Keith E. Livo, Gregory P. Meeker, Stephen J. Sutley, Geoffrey S. Plumlee, Betina Pavri, Charles M. Sarture, Joe Boardman, Isabelle Brownfield, Laurie C. Morath
Materials characterization of dusts generated by the collapse of the World Trade Center Materials characterization of dusts generated by the collapse of the World Trade Center
The major inorganic components of the dusts generated from the collapse of the World Trade Center buildings on September 11, 2001 were concrete materials, gypsum, and man-made vitreous fibers. These components were likely derived from lightweight Portland cement concrete floors, gypsum wallboard, and spray-on fireproofing and ceiling tiles, respectively. All of the 36 samples collected...
Authors
Gregory P. Meeker, Stephen J. Sutley, Isabelle Brownfield, Heather Lowers, Amy M. Bern, Gregg A. Swayze, Todd M. Hoefen, Geoffrey S. Plumlee, Roger N. Clark, Carol A. Gent
Science and Products
Filter Total Items: 113
Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates Simultaneous speciation of arsenic, selenium, and chromium: Species stability, sample preservation, and analysis of ash and soil leachates
An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic...
Authors
R.E. Wolf, S.A. Morman, P. L. Hageman, T.M. Hoefen, G.S. Plumlee
The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA
Mining operations began at a world-class vermiculite deposit at Vermiculite Mountain near Libby, Montana, circa 1920 and ended in 1990. Fibrous and asbestiform amphiboles intergrown with vermiculite ore are suspected to be a causative factor in an abnormally high number of cases of respiratory diseases in former mine and mill workers, and in residents of Libby. The question addressed in...
Authors
William H. Langer, Bradley S. Van Gosen, Gregory P. Meeker, David T. Adams, Todd M. Hoefen
Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes
In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for...
Authors
Ruth E. Wolf, Todd M. Hoefen, Philip L. Hageman, Suzette A. Morman, Geoffrey S. Plumlee
Detection and mapping of hydrocarbon deposits on Titan Detection and mapping of hydrocarbon deposits on Titan
We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH4), and clouds of hydrogen cyanide (HCN) aerosols using diagnostic spectral features...
Authors
Roger N. Clark, J. M. Curchin, Jason W. Barnes, Ralf Jaumann, Laurence A. Soderblom, Dale P. Cruikshank, Robert H. Brown, Sebastien Rodriguez, Jonathan Lunine, Katrin Stephan, Todd M. Hoefen, Stephane Le Mouelic, Christophe Sotin, Kevin H. Baines, Bonnie J. Buratti, Philip D. Nicholson
A method for quantitative mapping of thick oil spills using imaging spectroscopy A method for quantitative mapping of thick oil spills using imaging spectroscopy
In response to the Deepwater Horizon oil spill in the Gulf of Mexico, a method of near-infrared imaging spectroscopic analysis was developed to map the locations of thick oil floating on water. Specifically, this method can be used to derive, in each image pixel, the oil-to-water ratio in oil emulsions, the sub-pixel areal fraction, and its thicknesses and volume within the limits of...
Authors
Roger N. Clark, Gregg A. Swayze, Ira Leifer, K. Eric Livo, Raymond F. Kokaly, Todd Hoefen, Sarah Lundeen, Michael Eastwood, Robert O. Green, Neil Pearson, Charles Sarture, Ian McCubbin, Dar Roberts, Eliza Bradley, Denis Steele, Thomas Ryan, Roseanne Dominguez
A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data
This report describes a method to create color-composite images indicative of thick oil:water emulsions on the surface of clear, deep ocean water by using normalized difference ratios derived from remotely sensed data collected by an imaging spectrometer. The spectral bands used in the normalized difference ratios are located in wavelength regions where the spectra of thick oil:water...
Authors
Raymond F. Kokaly, Todd M. Hoefen, K. Eric Livo, Gregg A. Swayze, Ira Leifer, Ian B. McCubbin, Michael L. Eastwood, Robert O. Green, Sarah R. Lundeen, Charles M. Sarture, Denis Steele, Thomas Ryan, Eliza S. Bradley, Dar A. Roberts
Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team
All of the calculations and results in this report are preliminary and intended for the purpose, and only for the purpose, of aiding the incident team in assessing the extent of the spilled oil for ongoing response efforts. Other applications of this report are not authorized and are not considered valid. Because of time constraints and limitations of data available to the experts, many...
Authors
Victor F. Labson, Roger N. Clark, Gregg A. Swayze, Todd M. Hoefen, Raymond F. Kokaly, K. Eric Livo, Michael H. Powers, Geoffrey S. Plumlee, Gregory P. Meeker
A method for qualitative mapping of thick oil spills using imaging spectroscopy A method for qualitative mapping of thick oil spills using imaging spectroscopy
A method is described to create qualitative images of thick oil in oil spills on water using near-infrared imaging spectroscopy data. The method uses simple 'three-point-band depths' computed for each pixel in an imaging spectrometer image cube using the organic absorption features due to chemical bonds in aliphatic hydrocarbons at 1.2, 1.7, and 2.3 microns. The method is not...
Authors
Roger N. Clark, Gregg A. Swayze, Ira Leifer, K. Eric Livo, Sarah Lundeen, Michael Eastwood, Robert O. Green, Raymond F. Kokaly, Todd Hoefen, Charles Sarture, Ian McCubbin, Dar Roberts, Denis Steele, Thomas Ryan, Roseanne Dominguez, Neil Pearson
Examination of Libby, Montana, Fill Material for Background Levels of Amphibole from the Rainy Creek Complex Using Scanning Electron Microscopy and X-Ray Microanalysis Examination of Libby, Montana, Fill Material for Background Levels of Amphibole from the Rainy Creek Complex Using Scanning Electron Microscopy and X-Ray Microanalysis
Natural background levels of Libby-type amphibole in the sediment of the Libby valley in Montana have not, up to this point, been determined. The purpose of this report is to provide the preliminary findings of a study designed by both the U.S. Geological Survey and the U.S. Environmental Protection Agency and performed by the U.S. Geological Survey. The study worked to constrain the...
Authors
David T. Adams, William H. Langer, Todd M. Hoefen, Bradley S. Van Gosen, Gregory P. Meeker
Sample collection of ash and burned soils from the October 2007 southern California Wildfires Sample collection of ash and burned soils from the October 2007 southern California Wildfires
Between November 2 through 9, 2007 scientists from the U.S. Geological Survey (USGS) collected samples of ash and burned soils from 28 sites in six areas burned as a result of the Southern California wildfires of October 2007, including the Harris, Witch, Santiago, Ammo, Canyon, and Grass Valley Fires. The primary goal of this sampling and analysis effort was to understand how...
Authors
Todd M. Hoefen, Raymond F. Kokaly, Deborah A. Martin, Carlton J. Rochester, Geoffrey S. Plumlee, Greg Mendez, Eric G. Reichard, Robert N. Fisher
Environmental mapping of the World Trade Center area with imaging spectroscopy after the September 11, 2001 attack Environmental mapping of the World Trade Center area with imaging spectroscopy after the September 11, 2001 attack
The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) was flown over the World Trade Center area on September 16, 18, 22, and 23, 2001. The data were used to map the WTC debris plume and its contents, including the spectral signatures of asbestiform minerals. Samples were collected and used as ground truth for the AVARIS mapping. A number of thermal hot spots were observed with...
Authors
Roger N. Clark, Gregg A. Swayze, Todd M. Hoefen, Robert O. Green, Keith E. Livo, Gregory P. Meeker, Stephen J. Sutley, Geoffrey S. Plumlee, Betina Pavri, Charles M. Sarture, Joe Boardman, Isabelle Brownfield, Laurie C. Morath
Materials characterization of dusts generated by the collapse of the World Trade Center Materials characterization of dusts generated by the collapse of the World Trade Center
The major inorganic components of the dusts generated from the collapse of the World Trade Center buildings on September 11, 2001 were concrete materials, gypsum, and man-made vitreous fibers. These components were likely derived from lightweight Portland cement concrete floors, gypsum wallboard, and spray-on fireproofing and ceiling tiles, respectively. All of the 36 samples collected...
Authors
Gregory P. Meeker, Stephen J. Sutley, Isabelle Brownfield, Heather Lowers, Amy M. Bern, Gregg A. Swayze, Todd M. Hoefen, Geoffrey S. Plumlee, Roger N. Clark, Carol A. Gent