Neil C Terry, PhD is a a research hydrologist at the USGS New York Water Science Center.
I am a research hydrologist at the USGS New York Water Science Center, where I specialize in near-surface geophysics, modeling, and water-related projects. Particular focus areas include groundwater quality monitoring, hydrogeological characterization, contaminant detection, and groundwater-surface water interactions. I also lead and support software/methods development efforts, specifically focusing on linking electrical geophysical measurements with soil and hydrogeological properties.
Prior to joining the USGS, my PhD work at Rutgers University centered around hydrogeophysical approaches to characterize and study processes occurring in wetlands - particularly carbon gas cycling in peatlands. During this time, I also participated in critical zone characterization and archaeological studies, among other projects. My MS work at the University at Buffalo primarily involved linking geophysical data to soil moisture distributions through coupled geophysical and unsaturated flow models in a Bayesian framework.
Professional Experience
A research hydrologist at the USGS New York Water Science Center.
Education and Certifications
PhD at Rutgers University
MS at the University of Buffalo
Science and Products
What does groundwater have to do with ice in Alaska?
USGS scientists are working alongside university researchers in Alaska to understand how groundwater and permafrost conditions change over time due to seasonal variations and climate change. Changes in permafrost can pose a threat to built infrastructure (like roads, homes, and pipelines) and to valued ecological resources that provide important habitats for wildlife.
Filter Total Items: 21
Floating Transient Electromagnetic Survey Data from the Columbia River near Hanford, WA
This data release contains motorboat-towed floating transient electromagnetic data collected from the Columbia River near Hanford WA. Data were collected using a ~16 foot (4.9 meters) outboard motorboat during two field campaigns: July 2021 and April 2022. In total, several hundred linear kilometers of data were collected from a reach of the Columbia that extends from approximately Vernita Bridge
Floating Electromagnetic Surveys from the Lower Delaware River Basin
Electromagnetic (EM) geophysical methods provide information about the bulk electrical conductivity of the subsurface. EM data has been widely used to investigate aquifers and geologic structures. In the following study, the United States Geological Survey conducted a boat-towed, waterborne transient electromagnetic (FloaTEM) survey to examine conductivity within the subsurface of the main Delawar
Geophysical and Other Data From an Irrigation Monitoring Experiment at Haddam Meadows, CT, July 2019
An irrigation monitoring experiment was performed in Haddam Meadows State Park, Connecticut, on July 16, 2019. Prior to this experiment, ground penetrating radar (GPR), frequency domain electromagnetics (FDEM), and electrical resistivity tomography (ERT) geophysical data were collected over a 20 meter by 10-meter grid to provide baseline information. A vertical soil moisture probe was installed in
Main channel river water temperature collected along the East Branch, West Branch, and mainstem Delaware River down to Lordville near Handcock, NY, USA in summer 2021
The Upper Delaware River is a unique example of an aquatic system where summer river temperature is actively managed for ecological purposes. River temperature at the mainstem Delaware River at Lordville, NY gage (USGS 01427207) is targeted to remain below 25 degrees C, with warm events potentially mitigated via directed upstream reservoir releases, a process guided by predictive tools. These dire
Stream Temperature, Dissolved Radon, and Stable Water Isotope Data Collected along Headwater Streams in the Upper Neversink River Watershed, NY, USA (ver. 2.0, April 2023)
This data release contains three data types that could potentially be used to infer spatiotemporal variability in groundwater discharge processes, along with other research and monitoring purposes: 1) Temporally continuous stream channel water temperature and adjacent streambank air temperature time series data (generally starting November 2020) as well as limited temperature data from May to Octo
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Upper part of the Delaware River between Hancock and Port Jervis, New York, June-July 2021
This data release contains waterborne gradient self-potential (SP), surface-water temperature, surface-water conductivity and specific conductance, and surface-water nitrate concentration data measured continuously in the upper part of the Delaware River along approximately 123 kilometers (km) between Hancock and Port Jervis, New York. All of the data were measured from a kayak between June 27 and
Passive seismic (HVSR) data from Fountain Creek, CO
A total of 119 passive seismic soundings were collected with Tromino (MoHo s.r.l.) 3-axis seismometers in the Fountain Creek area to partially refine alluvial aquifer thickness (depth to bedrock) estimates, particularly over known or suspected paleochannels. Data were collected during June 21-24, 2021 with a team of 4-5 people, each equipped with a Tromino Blu or Tromino 3G passive seismometer.
Frequency domain electromagnetic induction (FDEM) geophysical data collected near the Agashashok River in the Noatak National Preserve, AK
Frequency domain electromagnetic induction (FDEM) data were collected in September 2016 near the Agashashok River and its tributaries, within the Noatak National Preserve near Kotzebue, AK to aid in local permafrost mapping. Data were collected with a GEM-2 instrument (1.6 m coil separation, Geophex, Ltd.); a broadband sensor that measures the bulk conductivity and magnetic susceptibility of the s
Selected borehole geophysical logs from three contaminant sites in California, Wisconsin, and New Jersey
Borehole geophysical logs were collected to characterize bedrock aquifers at three contamination sites located in California, Wisconsin, and New Jersey. The data were collected by the U.S. Geological Survey (USGS) and the University of Guelph from 2014 to 2015 as part of the U.S. Department of Defense Strategic Environmental Research and Development Program (SERDP) and Environmental Security Techn
Depth to bedrock determined from passive seismic measurements, Neversink River watershed, NY (USA)
This data release documents streambed sediment thickness in the Neversink watershed (NY) as determined by field observations and HVSR passive seismic measurements, and were collected as an extension of a previous data set collected in the same watershed (see Associated Items). These measurements were made between May 17, 2021 and May 21, 2021 using MOHO Tromino three-component seismometers (MOHO,
Data used to estimate groundwater salinity above the Montebello oil field (California, USA)
This release contains borehole geophysical electrical log data (elogs), total dissolved solids sample data (TDS), and geostatistical program files used to estimate the salinity distribution in groundwater above and in the vicinity of the Montebello Oil Field, located near Los Angeles, California, USA. Original data are drawn from a variety of publicly available sources and are combined here for us
Near-surface geophysical data collected along French Gulch near Breckenridge, Colorado, USA, September 2020
Near-surface geophysical surveys were completed in September 2020 in a mine-affected drainage near Breckenridge, Colorado, known as French Gulch. The study area was along a 0.3 mile (0.5 kilometer [km]) reach of French Gulch, approximately 2 river miles upstream from its confluence with the Blue River. This data release presents data from three geophysical surveys that used fiber-optic distributed
Filter Total Items: 15
Paired Air and Stream Temperature Analysis (PASTA) to evaluate groundwater influence on streams
Groundwater is critical for maintaining stream baseflow and thermal stability; however, the influence of groundwater on streamflow has been difficult to evaluate at broad spatial scales. Techniques such as baseflow separation necessitate streamflow records and do not directly indicate whether groundwater inflow may be sourced from more dynamic shallow flowpaths. We present a web tool application P
Authors
Danielle K. Hare, Susanne A. Benz, Barret L. Kurylyk, Zachary Johnson, Neil Terry, Ashley M. Helton
Field evaluation of semi-automated moisture estimation from geophysics using machine learning
Geophysical methods can provide three-dimensional (3D), spatially continuous estimates of soil moisture. However, point-to-point comparisons of geophysical properties to measure soil moisture data are frequently unsatisfactory, resulting in geophysics being used for qualitative purposes only. This is because (1) geophysics requires models that relate geophysical signals to soil moisture, (2) geoph
Authors
Neil Terry, F.D. Day-Lewis, John W. Lane, Carole D. Johnson, Dale Werkema
Interaction of a legacy groundwater contaminant plume with the Little Wind River from 2015 through 2017, Riverton Processing site, Wyoming
The Riverton Processing site was a uranium mill 4 kilometers southwest of Riverton, Wyoming, that prepared uranium ore for nuclear reactors and weapons from 1958 to 1963. The U.S. Department of Energy completed surface remediation of the uranium tailings in 1989; however, groundwater below and downgradient from the tailings site and nearby Little Wind River was not remediated. Beginning in 2010, a
Authors
David L. Naftz, Christopher C. Fuller, Robert L. Runkel, John Solder, W. Payton Gardner, Neil Terry, Martin A. Briggs, Terry M. Short, Daniel J. Cain, William L Dam, Patrick A. Byrne, James R. Campbell
Geostatistical mapping of salinity conditioned on borehole logs, Montebello Oil Field, California
We present a geostatistics-based stochastic salinity estimation framework for the Montebello Oil Field that capitalizes on available total dissolved solids (TDS) data from groundwater samples as well as electrical resistivity (ER) data from borehole logging. Data from TDS samples (n = 4924) was coded into an indicator framework based on falling below four selected thresholds (500, 1000, 3000, and
Authors
Neil Terry, Frederick Day-Lewis, Matthew K. Landon, Michael Land, Jennifer S. Stanton, John W. Lane
Beware of spatial autocorrelation when applying machine learning algorithms to borehole geophysical logs
Although many of the algorithms now considered to be machine learning algorithms (MLAs) have existed for nearly a century (e.g., Rosenblatt 1958), interest in MLAs has recently increased exponentially for solving data-driven problems across a variety of fields due to the expanded availability of large, complex datasets that may be difficult to interrogate using other methods, increases in computin
Authors
Neil Terry, Carole D. Johnson, Frederick Day-Lewis, Beth L. Parker, Lee D. Slater
Aufeis fields as novel groundwater-dependent ecosystems in the arctic cryosphere
River aufeis (ow′ fīse) are widespread features of the arctic cryosphere. They form when river channels become locally restricted by ice, resulting in cycles of water overflow and freezing and the accumulation of ice, with some aufeis attaining areas of ~ 25 + km2 and thicknesses of 6+ m. During winter, unfrozen sediments beneath the insulating ice layer provide perennial groundwater‐habitat that
Authors
Alexander D. Huryn, M. Gooseff, P. Hendrickson, Martin A. Briggs, K. Tape, Neil Terry
Exploring the potential of ground-penetrating radar (GPR) to measure the extent of chronic disturbance in peatlands: Examples from acid mine drainage and peat fire
Peatlands are accumulations of partially decayed organic soil that cover approximately 3% of Earth’s surface and have been shown to serve essential environmental and ecological functions such as sequestering carbon, purifying water, and providing habitat for organisms. However, peatlands are threatened by pressures from agriculture, urban development, mining, and climate change. Geophysical method
Authors
Neil Terry, Robert L. Runkel, Dale D. Werkema, Elizabeth Rutila, Xavier Comas, Matthew Warren, Agus Kristiyono, Daniel Murdiyarso
Characterizing the diverse hydrogeology underlying rivers and estuaries using new floating transient electromagnetic methodology
The hydrogeology below large surface water features such as rivers and estuaries is universally under-informed at the long reach to basin scales (tens of km+). This challenge inhibits the accurate modeling of fresh/saline groundwater interfaces and groundwater/surface water exchange patterns at management-relevant spatial extents. Here we introduce a towed, floating transient electromagnetic (TEM)
Authors
John W. Lane, Martin A. Briggs, PK Maurya, Eric A. White, JB Pedersen, Esben Auken, Neil Terry, Burke J. Minsley, Wade Kress, Denis R. LeBlanc, Ryan F. Adams, Carole D. Johnson
Seasonal subsurface thaw dynamics of an aufeis feature inferred from geophysical methods
Aufeis are sheets of ice unique to cold regions that originate from repeated flooding and freezing events during the winter. They have hydrological importance associated with summer flows and possibly winter insulation, but little is known about the seasonal dynamics of the unfrozen sediment layer beneath them. This layer may support perennial groundwater flow in regions with otherwise continuous
Authors
Neil Terry, Elliot Grunewald, Martin A. Briggs, Michael Gooseff, Alexander D. Huryn, M. Andy Kass, Ken Tape, Patrick Hendrickson, John W. Lane
Controls on spatial and temporal variations of brine discharge to the Dolores River in the Paradox Valley, Colorado, 2016–18
The Paradox Valley in southwestern Colorado is a collapsed anticline formed by movement of the salt-rich Paradox Formation at the core of the anticline. The salinity of the Dolores River, a tributary of the Colorado River, increases substantially as it crosses the valley because of discharge of brine-rich groundwater derived from the underlying salts. Although the brine is naturally occurring, it
Authors
Alisa Mast, Neil Terry
Geophysical mapping of plume discharge to surface water at a crude oil spill site: Inversion versus machine learning
The interpretation of geophysical survey results to answer hydrologic, engineering, and geologic questions is critical to diverse problems for management of water, energy, and mineral resources. Although geophysical images provide valuable qualitative insight into subsurface architecture and conditions, translating geophysical images into quantitative information (e.g., saturation, concentration,
Authors
Neil Terry, Frederick D. Day-Lewis, John W. Lane, Jared J. Trost, Barbara A. Bekins
Geophysical assessment of a proposed landfill site in Fredericktown, Missouri
In June 2018, U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency (EPA) collected geophysical measurements to help evaluate the suitability of a proposed landfill site for disposing mine-waste materials in Fredericktown, MO. The geophysical investigation included electromagnetic induction, electrical resistivity tomography, horizontal-to-vertical spectral ratio pass
Authors
Carole D. Johnson, Eric A. White, Dale D. Werkema, Neil Terry, Stephanie N. Phillips, Robert Ford, John W. Lane
Non-USGS Publications**
Terry, N. and Slater, L. ( 2017), Gas bubble size estimation in peat soils from EM wave scattering observed with ground penetrating radar, Water Resour. Res., 53, 2755– 2769, doi:10.1002/2016WR019783.
Day-Lewis, F. D., Slater, L. D., Robinson, J., Johnson, C. D., Terry, N., and Werkema, D. (2017), An overview of geophysical technologies appropriate for characterization and monitoring at fractured-rock sites, Journal of Environmental Management, 204, 709-720, doi: https://doi.org/10.1016/j.jenvman.2017.04.033.
Comas, X., Terry, N., Hribljan, J. A., Lilleskov, E. A., Suarez, E., Chimner, R. A., and Kolka, R. K. ( 2017), Estimating belowground carbon stocks in peatlands of the Ecuadorian páramo using ground‐penetrating radar (GPR), J. Geophys. Res. Biogeosci., 122, 370– 386, doi:10.1002/2016JG003550.
Terry, N., Slater, L., Comas, X., Reeve, A. S., Schäfer, K. V. R., and Yu, Z. ( 2016), Free phase gas processes in a northern peatland inferred from autonomous field‐scale resistivity imaging, Water Resour. Res., 52, 2996– 3018, doi:10.1002/2015WR018111.
Comas, X., Terry, N., Slater, L., Warren, M., Kolka, R., Kristiyono, A., Sudiana, N., Nurjaman, D., and Darusman, T.: Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization, Biogeosciences, 12, 2995–3007, https://doi.org/10.5194/bg-12-2995-2015, 2015.
**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.
RDAVT
RDAVT.r is an R Shiny-based app used to estimate immobile porosity, mobile porosity, and the mass transfer rate coefficient in dual-domain porosity media. The app allows for interactive fitting of the fluid versus bulk conductivity hysteresis curve from electrical tracer experiments using a semi-analytic graphical approach.
FLASH-R (Flow-Log Analysis of Single Holes)
FLASH-R (Flow-Log Analysis of Single Holes) is an R app for the analysis of borehole vertical flow logs to estimate fracture (or layer) transmissivities and far-field hydraulic heads.
This app is a new version of the FLASH spreadsheet tool by Day-Lewis et al. (2011) . The program is written in R, an open-source environment.
All previous features have been retained and new features incorporated i
FLASH-R: Flow-Log Analysis of Single Holes
FLASH-R (Flow-Log Analysis of Single Holes) is an R app for the analysis of borehole vertical flow logs to estimate fracture (or layer) transmissivities and far-field hydraulic heads.
MoisturEC
MoisturEC is an R-based GUI used to combine electrical conductivity (EC) data with point moisture measurements for an updated moisture estimate capitalizing on the accuracy of point moisture measurements and the spatial coverage of EC data.
MoisturEC: R-based GUI to combine electrical conductivity data with point moisture measurements
MoisturEC is an R-based GUI used to combine electrical conductivity (EC) data with point moisture measurements for an updated moisture estimate capitalizing on the accuracy of point moisture measurements and the spatial coverage of EC data.
Scenario Evaluator for Electrical Resistivity (SEER) Survey Pre-Modeling Tool
The USGS Scenario Evaluator for Electrical Resistivity (SEER) is a quick and simple Excel-based decision support tool practitioners can use to assess the likely outcome of using two-dimensional (2D) electrical resistivity imaging for site characterization and remediation monitoring.
Science and Products
- Science
What does groundwater have to do with ice in Alaska?
USGS scientists are working alongside university researchers in Alaska to understand how groundwater and permafrost conditions change over time due to seasonal variations and climate change. Changes in permafrost can pose a threat to built infrastructure (like roads, homes, and pipelines) and to valued ecological resources that provide important habitats for wildlife. - Data
Filter Total Items: 21
Floating Transient Electromagnetic Survey Data from the Columbia River near Hanford, WA
This data release contains motorboat-towed floating transient electromagnetic data collected from the Columbia River near Hanford WA. Data were collected using a ~16 foot (4.9 meters) outboard motorboat during two field campaigns: July 2021 and April 2022. In total, several hundred linear kilometers of data were collected from a reach of the Columbia that extends from approximately Vernita BridgeFloating Electromagnetic Surveys from the Lower Delaware River Basin
Electromagnetic (EM) geophysical methods provide information about the bulk electrical conductivity of the subsurface. EM data has been widely used to investigate aquifers and geologic structures. In the following study, the United States Geological Survey conducted a boat-towed, waterborne transient electromagnetic (FloaTEM) survey to examine conductivity within the subsurface of the main DelawarGeophysical and Other Data From an Irrigation Monitoring Experiment at Haddam Meadows, CT, July 2019
An irrigation monitoring experiment was performed in Haddam Meadows State Park, Connecticut, on July 16, 2019. Prior to this experiment, ground penetrating radar (GPR), frequency domain electromagnetics (FDEM), and electrical resistivity tomography (ERT) geophysical data were collected over a 20 meter by 10-meter grid to provide baseline information. A vertical soil moisture probe was installed inMain channel river water temperature collected along the East Branch, West Branch, and mainstem Delaware River down to Lordville near Handcock, NY, USA in summer 2021
The Upper Delaware River is a unique example of an aquatic system where summer river temperature is actively managed for ecological purposes. River temperature at the mainstem Delaware River at Lordville, NY gage (USGS 01427207) is targeted to remain below 25 degrees C, with warm events potentially mitigated via directed upstream reservoir releases, a process guided by predictive tools. These direStream Temperature, Dissolved Radon, and Stable Water Isotope Data Collected along Headwater Streams in the Upper Neversink River Watershed, NY, USA (ver. 2.0, April 2023)
This data release contains three data types that could potentially be used to infer spatiotemporal variability in groundwater discharge processes, along with other research and monitoring purposes: 1) Temporally continuous stream channel water temperature and adjacent streambank air temperature time series data (generally starting November 2020) as well as limited temperature data from May to OctoWaterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Upper part of the Delaware River between Hancock and Port Jervis, New York, June-July 2021
This data release contains waterborne gradient self-potential (SP), surface-water temperature, surface-water conductivity and specific conductance, and surface-water nitrate concentration data measured continuously in the upper part of the Delaware River along approximately 123 kilometers (km) between Hancock and Port Jervis, New York. All of the data were measured from a kayak between June 27 andPassive seismic (HVSR) data from Fountain Creek, CO
A total of 119 passive seismic soundings were collected with Tromino (MoHo s.r.l.) 3-axis seismometers in the Fountain Creek area to partially refine alluvial aquifer thickness (depth to bedrock) estimates, particularly over known or suspected paleochannels. Data were collected during June 21-24, 2021 with a team of 4-5 people, each equipped with a Tromino Blu or Tromino 3G passive seismometer.Frequency domain electromagnetic induction (FDEM) geophysical data collected near the Agashashok River in the Noatak National Preserve, AK
Frequency domain electromagnetic induction (FDEM) data were collected in September 2016 near the Agashashok River and its tributaries, within the Noatak National Preserve near Kotzebue, AK to aid in local permafrost mapping. Data were collected with a GEM-2 instrument (1.6 m coil separation, Geophex, Ltd.); a broadband sensor that measures the bulk conductivity and magnetic susceptibility of the sSelected borehole geophysical logs from three contaminant sites in California, Wisconsin, and New Jersey
Borehole geophysical logs were collected to characterize bedrock aquifers at three contamination sites located in California, Wisconsin, and New Jersey. The data were collected by the U.S. Geological Survey (USGS) and the University of Guelph from 2014 to 2015 as part of the U.S. Department of Defense Strategic Environmental Research and Development Program (SERDP) and Environmental Security TechnDepth to bedrock determined from passive seismic measurements, Neversink River watershed, NY (USA)
This data release documents streambed sediment thickness in the Neversink watershed (NY) as determined by field observations and HVSR passive seismic measurements, and were collected as an extension of a previous data set collected in the same watershed (see Associated Items). These measurements were made between May 17, 2021 and May 21, 2021 using MOHO Tromino three-component seismometers (MOHO,Data used to estimate groundwater salinity above the Montebello oil field (California, USA)
This release contains borehole geophysical electrical log data (elogs), total dissolved solids sample data (TDS), and geostatistical program files used to estimate the salinity distribution in groundwater above and in the vicinity of the Montebello Oil Field, located near Los Angeles, California, USA. Original data are drawn from a variety of publicly available sources and are combined here for usNear-surface geophysical data collected along French Gulch near Breckenridge, Colorado, USA, September 2020
Near-surface geophysical surveys were completed in September 2020 in a mine-affected drainage near Breckenridge, Colorado, known as French Gulch. The study area was along a 0.3 mile (0.5 kilometer [km]) reach of French Gulch, approximately 2 river miles upstream from its confluence with the Blue River. This data release presents data from three geophysical surveys that used fiber-optic distributed - Multimedia
- Publications
Filter Total Items: 15
Paired Air and Stream Temperature Analysis (PASTA) to evaluate groundwater influence on streams
Groundwater is critical for maintaining stream baseflow and thermal stability; however, the influence of groundwater on streamflow has been difficult to evaluate at broad spatial scales. Techniques such as baseflow separation necessitate streamflow records and do not directly indicate whether groundwater inflow may be sourced from more dynamic shallow flowpaths. We present a web tool application PAuthorsDanielle K. Hare, Susanne A. Benz, Barret L. Kurylyk, Zachary Johnson, Neil Terry, Ashley M. HeltonField evaluation of semi-automated moisture estimation from geophysics using machine learning
Geophysical methods can provide three-dimensional (3D), spatially continuous estimates of soil moisture. However, point-to-point comparisons of geophysical properties to measure soil moisture data are frequently unsatisfactory, resulting in geophysics being used for qualitative purposes only. This is because (1) geophysics requires models that relate geophysical signals to soil moisture, (2) geophAuthorsNeil Terry, F.D. Day-Lewis, John W. Lane, Carole D. Johnson, Dale WerkemaInteraction of a legacy groundwater contaminant plume with the Little Wind River from 2015 through 2017, Riverton Processing site, Wyoming
The Riverton Processing site was a uranium mill 4 kilometers southwest of Riverton, Wyoming, that prepared uranium ore for nuclear reactors and weapons from 1958 to 1963. The U.S. Department of Energy completed surface remediation of the uranium tailings in 1989; however, groundwater below and downgradient from the tailings site and nearby Little Wind River was not remediated. Beginning in 2010, aAuthorsDavid L. Naftz, Christopher C. Fuller, Robert L. Runkel, John Solder, W. Payton Gardner, Neil Terry, Martin A. Briggs, Terry M. Short, Daniel J. Cain, William L Dam, Patrick A. Byrne, James R. CampbellGeostatistical mapping of salinity conditioned on borehole logs, Montebello Oil Field, California
We present a geostatistics-based stochastic salinity estimation framework for the Montebello Oil Field that capitalizes on available total dissolved solids (TDS) data from groundwater samples as well as electrical resistivity (ER) data from borehole logging. Data from TDS samples (n = 4924) was coded into an indicator framework based on falling below four selected thresholds (500, 1000, 3000, andAuthorsNeil Terry, Frederick Day-Lewis, Matthew K. Landon, Michael Land, Jennifer S. Stanton, John W. LaneBeware of spatial autocorrelation when applying machine learning algorithms to borehole geophysical logs
Although many of the algorithms now considered to be machine learning algorithms (MLAs) have existed for nearly a century (e.g., Rosenblatt 1958), interest in MLAs has recently increased exponentially for solving data-driven problems across a variety of fields due to the expanded availability of large, complex datasets that may be difficult to interrogate using other methods, increases in computinAuthorsNeil Terry, Carole D. Johnson, Frederick Day-Lewis, Beth L. Parker, Lee D. SlaterAufeis fields as novel groundwater-dependent ecosystems in the arctic cryosphere
River aufeis (ow′ fīse) are widespread features of the arctic cryosphere. They form when river channels become locally restricted by ice, resulting in cycles of water overflow and freezing and the accumulation of ice, with some aufeis attaining areas of ~ 25 + km2 and thicknesses of 6+ m. During winter, unfrozen sediments beneath the insulating ice layer provide perennial groundwater‐habitat thatAuthorsAlexander D. Huryn, M. Gooseff, P. Hendrickson, Martin A. Briggs, K. Tape, Neil TerryExploring the potential of ground-penetrating radar (GPR) to measure the extent of chronic disturbance in peatlands: Examples from acid mine drainage and peat fire
Peatlands are accumulations of partially decayed organic soil that cover approximately 3% of Earth’s surface and have been shown to serve essential environmental and ecological functions such as sequestering carbon, purifying water, and providing habitat for organisms. However, peatlands are threatened by pressures from agriculture, urban development, mining, and climate change. Geophysical methodAuthorsNeil Terry, Robert L. Runkel, Dale D. Werkema, Elizabeth Rutila, Xavier Comas, Matthew Warren, Agus Kristiyono, Daniel MurdiyarsoCharacterizing the diverse hydrogeology underlying rivers and estuaries using new floating transient electromagnetic methodology
The hydrogeology below large surface water features such as rivers and estuaries is universally under-informed at the long reach to basin scales (tens of km+). This challenge inhibits the accurate modeling of fresh/saline groundwater interfaces and groundwater/surface water exchange patterns at management-relevant spatial extents. Here we introduce a towed, floating transient electromagnetic (TEM)AuthorsJohn W. Lane, Martin A. Briggs, PK Maurya, Eric A. White, JB Pedersen, Esben Auken, Neil Terry, Burke J. Minsley, Wade Kress, Denis R. LeBlanc, Ryan F. Adams, Carole D. JohnsonSeasonal subsurface thaw dynamics of an aufeis feature inferred from geophysical methods
Aufeis are sheets of ice unique to cold regions that originate from repeated flooding and freezing events during the winter. They have hydrological importance associated with summer flows and possibly winter insulation, but little is known about the seasonal dynamics of the unfrozen sediment layer beneath them. This layer may support perennial groundwater flow in regions with otherwise continuousAuthorsNeil Terry, Elliot Grunewald, Martin A. Briggs, Michael Gooseff, Alexander D. Huryn, M. Andy Kass, Ken Tape, Patrick Hendrickson, John W. LaneControls on spatial and temporal variations of brine discharge to the Dolores River in the Paradox Valley, Colorado, 2016–18
The Paradox Valley in southwestern Colorado is a collapsed anticline formed by movement of the salt-rich Paradox Formation at the core of the anticline. The salinity of the Dolores River, a tributary of the Colorado River, increases substantially as it crosses the valley because of discharge of brine-rich groundwater derived from the underlying salts. Although the brine is naturally occurring, itAuthorsAlisa Mast, Neil TerryGeophysical mapping of plume discharge to surface water at a crude oil spill site: Inversion versus machine learning
The interpretation of geophysical survey results to answer hydrologic, engineering, and geologic questions is critical to diverse problems for management of water, energy, and mineral resources. Although geophysical images provide valuable qualitative insight into subsurface architecture and conditions, translating geophysical images into quantitative information (e.g., saturation, concentration,AuthorsNeil Terry, Frederick D. Day-Lewis, John W. Lane, Jared J. Trost, Barbara A. BekinsGeophysical assessment of a proposed landfill site in Fredericktown, Missouri
In June 2018, U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency (EPA) collected geophysical measurements to help evaluate the suitability of a proposed landfill site for disposing mine-waste materials in Fredericktown, MO. The geophysical investigation included electromagnetic induction, electrical resistivity tomography, horizontal-to-vertical spectral ratio passAuthorsCarole D. Johnson, Eric A. White, Dale D. Werkema, Neil Terry, Stephanie N. Phillips, Robert Ford, John W. LaneNon-USGS Publications**
Terry, N. and Slater, L. ( 2017), Gas bubble size estimation in peat soils from EM wave scattering observed with ground penetrating radar, Water Resour. Res., 53, 2755– 2769, doi:10.1002/2016WR019783.Day-Lewis, F. D., Slater, L. D., Robinson, J., Johnson, C. D., Terry, N., and Werkema, D. (2017), An overview of geophysical technologies appropriate for characterization and monitoring at fractured-rock sites, Journal of Environmental Management, 204, 709-720, doi: https://doi.org/10.1016/j.jenvman.2017.04.033.
Comas, X., Terry, N., Hribljan, J. A., Lilleskov, E. A., Suarez, E., Chimner, R. A., and Kolka, R. K. ( 2017), Estimating belowground carbon stocks in peatlands of the Ecuadorian páramo using ground‐penetrating radar (GPR), J. Geophys. Res. Biogeosci., 122, 370– 386, doi:10.1002/2016JG003550.Terry, N., Slater, L., Comas, X., Reeve, A. S., Schäfer, K. V. R., and Yu, Z. ( 2016), Free phase gas processes in a northern peatland inferred from autonomous field‐scale resistivity imaging, Water Resour. Res., 52, 2996– 3018, doi:10.1002/2015WR018111.Comas, X., Terry, N., Slater, L., Warren, M., Kolka, R., Kristiyono, A., Sudiana, N., Nurjaman, D., and Darusman, T.: Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization, Biogeosciences, 12, 2995–3007, https://doi.org/10.5194/bg-12-2995-2015, 2015.**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.
- Software
RDAVT
RDAVT.r is an R Shiny-based app used to estimate immobile porosity, mobile porosity, and the mass transfer rate coefficient in dual-domain porosity media. The app allows for interactive fitting of the fluid versus bulk conductivity hysteresis curve from electrical tracer experiments using a semi-analytic graphical approach.FLASH-R (Flow-Log Analysis of Single Holes)
FLASH-R (Flow-Log Analysis of Single Holes) is an R app for the analysis of borehole vertical flow logs to estimate fracture (or layer) transmissivities and far-field hydraulic heads. This app is a new version of the FLASH spreadsheet tool by Day-Lewis et al. (2011) . The program is written in R, an open-source environment. All previous features have been retained and new features incorporated iFLASH-R: Flow-Log Analysis of Single Holes
FLASH-R (Flow-Log Analysis of Single Holes) is an R app for the analysis of borehole vertical flow logs to estimate fracture (or layer) transmissivities and far-field hydraulic heads.
MoisturEC
MoisturEC is an R-based GUI used to combine electrical conductivity (EC) data with point moisture measurements for an updated moisture estimate capitalizing on the accuracy of point moisture measurements and the spatial coverage of EC data.MoisturEC: R-based GUI to combine electrical conductivity data with point moisture measurements
MoisturEC is an R-based GUI used to combine electrical conductivity (EC) data with point moisture measurements for an updated moisture estimate capitalizing on the accuracy of point moisture measurements and the spatial coverage of EC data.
Scenario Evaluator for Electrical Resistivity (SEER) Survey Pre-Modeling Tool
The USGS Scenario Evaluator for Electrical Resistivity (SEER) is a quick and simple Excel-based decision support tool practitioners can use to assess the likely outcome of using two-dimensional (2D) electrical resistivity imaging for site characterization and remediation monitoring.
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