Interdisciplinary Methods and Applications in Geophysics (IMAGe) Active
The project focuses on the development of novel geophysical techniques that improve our ability to understand Earth's subsurface, with broad relevance to the Mineral Resources Program and the USGS Science Strategy. Our goal is to develop and maintain state-of-the art geophysical capabilities that support the diverse science needs of USGS projects that aim to meet the challenges of the 21st century by helping to improve the economic and environmental health and prosperity of people and communities across the Nation and around the world.
Science Issue and Relevance
Mineral resource studies are fundamentally subsurface studies — from the need to characterize the geological structures that host important deposits to better understanding the landscape and environmental impacts of resource development, sophisticated geophysical methods and instruments are needed. Constantly evolving modern geophysical techniques, in particular airborne geophysical methods, present new opportunities for large-scale subsurface characterization, but also require new computational tools and software algorithms that translate geophysical datasets into meaningful interpretations that can support management decisions. The Mineral Resources Program, and the USGS as a whole, has a continuing need for the development of state-of-the-art geophysical methods and instruments that have application to mineral resource and mineral environmental studies.
Methods to Address Issue
The IMAGe project focuses on the development of novel geophysical techniques that improve our ability to understand Earth's subsurface, with broad relevance to the Mineral Resources Program and the USGS Science Strategy. Our goal is to develop and maintain state-of-the-art geophysical capabilities that support the diverse science needs of USGS projects that aim to meet the challenges of the 21st century by helping to improve the economic and environmental health and prosperity of people and communities across the Nation and around the world.
The main objectives of our research include:
Frontier Geophysical Methods: Develop novel data analysis and interpretation algorithms that help maintain USGS at the forefront of airborne geophysics. Activities will include:
- develop expertise in the use of fixed-wing airborne electromagnetic (AEM) systems which are effective for regional-scale mapping activities;
- evaluating tools for the analysis of airborne induced polarization effects, a cutting-edge approach to identifying mineralized geologic targets;
- evaluating nodal seismometers for passive seismic studies and developing open source workflows to facilitate use and analysis of these data;
- evaluation of compensation and calibration methods for UAS-based aeromagnetic surveys.
Computational Geophysics: Support maintenance of existing software codes developed over many years by Geology, Geophysics, and Geochemistry Science Center (GGGSC) researchers that are used for the processing and analysis of airborne potential field and electromagnetic datasets. Develop new advanced computational capabilities including cooperation with the USGS Advanced Research Computing (ARC) group to facilitate the implementation of geophysical codes on the USGS high-performance computing cluster (Yeti). Current focus includes:
- developing new algorithms for high performance and high throughput parallel computing needs in cooperation with GGGSC researchers,
- facilitating publication of new and existing codes through the USGS Github group,
- facilitate access and use of the Yeti high-performance computing system,
- developing hdf5 and netCDF data standards for geophysical datasets, along with open source workflows to facilitate processing, visualization, and archival of datasets.
Quantitative geologic inferences from integrated geophysical methods: Many geologic mapping targets are best resolved through the use of integrated geophysical methods that are sensitive to different physical characteristics. We will continue research into methods for combined geologic interpretations using multiple geophysical methods. Examples include: models of hydrothermally altered regions based on magnetic and resistivity data collected at Mt. Iliamna, AK, and models of the Stillwater layered mafic intrusion based on gravity, magnetic, and seismic reflection data.
Uncertainty quantification: There are two fundamental sources of uncertainty in developing geological interpretations from geophysical data. First is the underlying uncertainty in geophysical properties (e.g. electrical resistivity, magnetic susceptibility, density, or seismic velocity) given a specific type of geophysical survey along with measurement errors. The second is the uncertainty in the relationship between geophysical and geological properties. We will address multiple aspects of uncertainty quantification for different types of geophysical data. Work will include:
- Continued development of GeoBIPy open source software for uncertainty quantification of airborne electromagnetic data, and extension to other data types
- Probabilistic geologic modeling to quantify the uncertainty in geological model structure given prior expert knowledge, geophysical data, and other existing observations. One application will be to investigate uncertainty in the shape and location of carbonatite deposits in the Mountain Pass project based on gravity and magnetic data. We will also build tools to quantify geological model uncertainty based on airborne electromagnetic datasets along with geostatistical simulation tools.
- An open-source toolbox for physical property relationships and uncertainty. We will develop an source software application using Python that will allow users, in a stochastic framework, to estimate physical properties such as temperature, water content, clay content, partial melt, or porosity based on geophysical parameters such as resistivity, density, or magnetic susceptibility.
Facilities
Geophysical Test Site - In 2015, we began to establish a geophysical test site at the USGS Boulder Geomagnetic Observatory. We are continuing to collect new baseline datasets for a broad suite of geophysical instruments. The test site will be used to calibrate and assess the accuracy of in-house and commercial geophysical tools, to develop and test new instrumentation, and for training Geology, Geophysics, and Geochemistry Science Center scientists and partners.
Previous Project Activities
Geophysical Instrument Development - The USGS and its Mineral Resources Program required the development of new geophysical instrumentation, and the maintenance of existing geophysical instrumentation.
Alaska Geophysical Data Processing - Alaska is a geologic frontier with substantial mineral resource potential. Complex geology, limited outcrop, and high logistical costs make airborne geophysics essential for efficient reconnaissance. We performed an advanced analysis of electromagnetic data to map geologic trends, structural geologic and tectonic patterns, and identify key lithologies for direct integration with geologic framework and mineral potential studies.
Monthly Webinar Series - We coordinated an internal, monthly webinar series to highlight cutting-edge geophysical research and applications related to our project's research, as well as other innovative work related to remote sensing and geochemistry by Geology, Geophysics, and Geochemistry Science Center scientists and other USGS colleagues.
Petrophysics Laboratory - The Petrophysics Laboratory is a multi-user facility that provides physical property data of earth materials for geophysical research. The Laboratory is equipped to make physical property measurements on rocks and sediment including density, magnetic properties, electrical properties, and radiometric properties. Knowledge of a site's physical properties is an important asset in planning geophysical surveys; particularly in selection of an appropriate method and in selecting optimum survey parameters such as array size and frequency. Knowing the range of physical properties for a given area help refine geophysical interpretations and provide justification for constraining model input parameters. The integration of physical property data with mineralogical and geochemical data provides an important link between the rocks and ores to their observed geophysical signatures.
Geophysical Instrumentation Laboratory - The Geophysical Instrumentation Laboratory provides electronic, software, and mechanical design and fabrication services for projects within the Geology, Geophysics, and Geochemistry Science Center.
- Machine shop with tools for wood, metal, plastic, and fiberglass fabrication
- Expertise with LabVIEW software for data acquisition and signal processing
- Electronic design, analysis and fabrication capability includes signal filtering, digital logic and circuit design, and more
Return to Mineral Resources Program | Geology, Geophysics, and Geochemistry Science Center
Below are other science projects associated with this project.
Below are data or web applications associated with this project.
Below are publications associated with this project.
A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment
Down to Earth with an electric hazard from space
Automatic mapping of the base of aquifer — A case study from Morrill, Nebraska
Semiautomatic approaches to account for 3-D distortion of the electric field from local, near-surface structures in 3-D resistivity inversions of 3-D regional magnetotelluric data
Generation of 3-D hydrostratigraphic zones from dense airborne electromagnetic data to assess groundwater model prediction error
Semiautomatic mapping of permafrost in the Yukon Flats, Alaska
Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA
Geoelectric hazard maps for the continental United States
Construction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota
Acquisition of a unique onshore/offshore geophysical and geochemical dataset in the Northern Malawi (Nyasa) Rift
Highly conductive horizons in the Mesoproterozoic Belt-Purcell Basin: Sulfidic early basin strata as key markers of Cordilleran shortening and Eocene extension
Below are software products associated with this project.
Below are news stories associated with this project.
In addition to the USGS Geomagnetism Program and the USGS Advanced Research Computing group, below are external partners associated with this project.
- Overview
The project focuses on the development of novel geophysical techniques that improve our ability to understand Earth's subsurface, with broad relevance to the Mineral Resources Program and the USGS Science Strategy. Our goal is to develop and maintain state-of-the art geophysical capabilities that support the diverse science needs of USGS projects that aim to meet the challenges of the 21st century by helping to improve the economic and environmental health and prosperity of people and communities across the Nation and around the world.
Science Issue and Relevance
Mineral resource studies are fundamentally subsurface studies — from the need to characterize the geological structures that host important deposits to better understanding the landscape and environmental impacts of resource development, sophisticated geophysical methods and instruments are needed. Constantly evolving modern geophysical techniques, in particular airborne geophysical methods, present new opportunities for large-scale subsurface characterization, but also require new computational tools and software algorithms that translate geophysical datasets into meaningful interpretations that can support management decisions. The Mineral Resources Program, and the USGS as a whole, has a continuing need for the development of state-of-the-art geophysical methods and instruments that have application to mineral resource and mineral environmental studies.
Methods to Address Issue
The IMAGe project focuses on the development of novel geophysical techniques that improve our ability to understand Earth's subsurface, with broad relevance to the Mineral Resources Program and the USGS Science Strategy. Our goal is to develop and maintain state-of-the-art geophysical capabilities that support the diverse science needs of USGS projects that aim to meet the challenges of the 21st century by helping to improve the economic and environmental health and prosperity of people and communities across the Nation and around the world.
The main objectives of our research include:
Frontier Geophysical Methods: Develop novel data analysis and interpretation algorithms that help maintain USGS at the forefront of airborne geophysics. Activities will include:
- develop expertise in the use of fixed-wing airborne electromagnetic (AEM) systems which are effective for regional-scale mapping activities;
- evaluating tools for the analysis of airborne induced polarization effects, a cutting-edge approach to identifying mineralized geologic targets;
- evaluating nodal seismometers for passive seismic studies and developing open source workflows to facilitate use and analysis of these data;
- evaluation of compensation and calibration methods for UAS-based aeromagnetic surveys.
Computational Geophysics: Support maintenance of existing software codes developed over many years by Geology, Geophysics, and Geochemistry Science Center (GGGSC) researchers that are used for the processing and analysis of airborne potential field and electromagnetic datasets. Develop new advanced computational capabilities including cooperation with the USGS Advanced Research Computing (ARC) group to facilitate the implementation of geophysical codes on the USGS high-performance computing cluster (Yeti). Current focus includes:
- developing new algorithms for high performance and high throughput parallel computing needs in cooperation with GGGSC researchers,
- facilitating publication of new and existing codes through the USGS Github group,
- facilitate access and use of the Yeti high-performance computing system,
- developing hdf5 and netCDF data standards for geophysical datasets, along with open source workflows to facilitate processing, visualization, and archival of datasets.
Quantitative geologic inferences from integrated geophysical methods: Many geologic mapping targets are best resolved through the use of integrated geophysical methods that are sensitive to different physical characteristics. We will continue research into methods for combined geologic interpretations using multiple geophysical methods. Examples include: models of hydrothermally altered regions based on magnetic and resistivity data collected at Mt. Iliamna, AK, and models of the Stillwater layered mafic intrusion based on gravity, magnetic, and seismic reflection data.
Uncertainty quantification: There are two fundamental sources of uncertainty in developing geological interpretations from geophysical data. First is the underlying uncertainty in geophysical properties (e.g. electrical resistivity, magnetic susceptibility, density, or seismic velocity) given a specific type of geophysical survey along with measurement errors. The second is the uncertainty in the relationship between geophysical and geological properties. We will address multiple aspects of uncertainty quantification for different types of geophysical data. Work will include:
- Continued development of GeoBIPy open source software for uncertainty quantification of airborne electromagnetic data, and extension to other data types
- Probabilistic geologic modeling to quantify the uncertainty in geological model structure given prior expert knowledge, geophysical data, and other existing observations. One application will be to investigate uncertainty in the shape and location of carbonatite deposits in the Mountain Pass project based on gravity and magnetic data. We will also build tools to quantify geological model uncertainty based on airborne electromagnetic datasets along with geostatistical simulation tools.
- An open-source toolbox for physical property relationships and uncertainty. We will develop an source software application using Python that will allow users, in a stochastic framework, to estimate physical properties such as temperature, water content, clay content, partial melt, or porosity based on geophysical parameters such as resistivity, density, or magnetic susceptibility.
Facilities
Geophysical Test Site - In 2015, we began to establish a geophysical test site at the USGS Boulder Geomagnetic Observatory. We are continuing to collect new baseline datasets for a broad suite of geophysical instruments. The test site will be used to calibrate and assess the accuracy of in-house and commercial geophysical tools, to develop and test new instrumentation, and for training Geology, Geophysics, and Geochemistry Science Center scientists and partners.
Previous Project Activities
Geophysical Instrument Development - The USGS and its Mineral Resources Program required the development of new geophysical instrumentation, and the maintenance of existing geophysical instrumentation.
Alaska Geophysical Data Processing - Alaska is a geologic frontier with substantial mineral resource potential. Complex geology, limited outcrop, and high logistical costs make airborne geophysics essential for efficient reconnaissance. We performed an advanced analysis of electromagnetic data to map geologic trends, structural geologic and tectonic patterns, and identify key lithologies for direct integration with geologic framework and mineral potential studies.
Monthly Webinar Series - We coordinated an internal, monthly webinar series to highlight cutting-edge geophysical research and applications related to our project's research, as well as other innovative work related to remote sensing and geochemistry by Geology, Geophysics, and Geochemistry Science Center scientists and other USGS colleagues.
Petrophysics Laboratory - The Petrophysics Laboratory is a multi-user facility that provides physical property data of earth materials for geophysical research. The Laboratory is equipped to make physical property measurements on rocks and sediment including density, magnetic properties, electrical properties, and radiometric properties. Knowledge of a site's physical properties is an important asset in planning geophysical surveys; particularly in selection of an appropriate method and in selecting optimum survey parameters such as array size and frequency. Knowing the range of physical properties for a given area help refine geophysical interpretations and provide justification for constraining model input parameters. The integration of physical property data with mineralogical and geochemical data provides an important link between the rocks and ores to their observed geophysical signatures.
Geophysical Instrumentation Laboratory - The Geophysical Instrumentation Laboratory provides electronic, software, and mechanical design and fabrication services for projects within the Geology, Geophysics, and Geochemistry Science Center.
- Machine shop with tools for wood, metal, plastic, and fiberglass fabrication
- Expertise with LabVIEW software for data acquisition and signal processing
- Electronic design, analysis and fabrication capability includes signal filtering, digital logic and circuit design, and more
Return to Mineral Resources Program | Geology, Geophysics, and Geochemistry Science Center
- Science
Below are other science projects associated with this project.
- Data
Below are data or web applications associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 72A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near TaAuthorsV. J. S. Grauch, Paul W. Bauer, Benjamin J. Drenth, Keith I. KelsonUndiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment
A probabilistic mineral resource assessment of metal resources in undiscovered porphyry copper deposits of the Ural Mountains in Russia and Kazakhstan was done using a quantitative form of mineral resource assessment. Permissive tracts were delineated on the basis of mapped and inferred subsurface distributions of igneous rocks assigned to tectonic zones that include magmatic arcs where the occurrAuthorsJane M. Hammarstrom, Mark J. Mihalasky, Stephen Ludington, Jeffrey Phillips, Byron R. Berger, Paul Denning, Connie Dicken, John C. Mars, Michael L. Zientek, Richard J. Herrington, Reimar SeltmannDown to Earth with an electric hazard from space
In reaching across traditional disciplinary boundaries, solid-Earth geophysicists and space physicists are forging new collaborations to map magnetic-storm hazards for electric-power grids. Future progress in evaluation storm time geoelectric hazards will come primarily through monitoring, surveys, and modeling of related data.AuthorsJeffrey J. Love, Paul A. Bedrosian, Adam SchultzAutomatic mapping of the base of aquifer — A case study from Morrill, Nebraska
When a geologist sets up a geologic model, various types of disparate information may be available, such as exposures, boreholes, and (or) geophysical data. In recent years, the amount of geophysical data available has been increasing, a trend that is only expected to continue. It is nontrivial (and often, in practice, impossible) for the geologist to take all the details of the geophysical data iAuthorsMats Lundh Gulbrandsen, Lyndsay B. Ball, Burke J. Minsley, Thomas Mejer HansenSemiautomatic approaches to account for 3-D distortion of the electric field from local, near-surface structures in 3-D resistivity inversions of 3-D regional magnetotelluric data
This report summarizes the results of three-dimensional (3-D) resistivity inversion simulations that were performed to account for local 3-D distortion of the electric field in the presence of 3-D regional structure, without any a priori information on the actual 3-D distribution of the known subsurface geology. The methodology used a 3-D geologic model to create a 3-D resistivity forward (“known”AuthorsBrian D. RodriguezGeneration of 3-D hydrostratigraphic zones from dense airborne electromagnetic data to assess groundwater model prediction error
We present a new methodology to combine spatially dense high-resolution airborne electromagnetic (AEM) data and sparse borehole information to construct multiple plausible geological structures using a stochastic approach. The method developed allows for quantification of the performance of groundwater models built from different geological realizations of structure. Multiple structural realizatioAuthorsNikolaj K Christensen, Burke J. Minsley, Steen ChristensenSemiautomatic mapping of permafrost in the Yukon Flats, Alaska
Thawing of permafrost due to global warming can have major impacts on hydrogeological processes, climate feedback, arctic ecology, and local environments. To understand these effects and processes, it is crucial to know the distribution of permafrost. In this study we exploit the fact that airborne electromagnetic (AEM) data are sensitive to the distribution of permafrost and demonstrate how the dAuthorsMats Lundh Gulbrandsen, Burke J. Minsley, Lyndsay B. Ball, Thomas Mejer HansenMagnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA
High-resolution airborne magnetic and gravity gradiometry data provide the geophysical framework for evaluating the exploration potential of hidden iron oxide deposits in Mesoproterozoic basement rocks of southeast Missouri. The data are used to calculate mineral prospectivity for iron oxide-apatite (IOA) ± rare earth element (REE) and iron oxide-copper-gold (IOCG) deposits. Results delineate theAuthorsAnne E. McCafferty, Jeffrey Phillips, Rhonda L. DriscollGeoelectric hazard maps for the continental United States
In support of a multiagency project for assessing induction hazards, we present maps of extreme-value geoelectric amplitudes over about half of the continental United States. These maps are constructed using a parameterization of induction: estimates of Earth surface impedance, obtained at discrete geographic sites from magnetotelluric survey data, are convolved with latitude-dependent statisticalAuthorsJeffrey J. Love, Antti Pulkkinen, Paul A. Bedrosian, Seth Jonas, Anna Kelbert, Erin (Josh) Rigler, Carol Finn, Christopher Balch, Robert Rutledge, Richard Waggel, Andrew Sabata, Janet Kozyra, Carrie BlackConstruction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota
The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux aquifer consists of glacial outwash sands and gravels aAuthorsJoshua F. Valder, Gregory C. Delzer, Janet M. Carter, Bruce D. Smith, David V. SmithAcquisition of a unique onshore/offshore geophysical and geochemical dataset in the Northern Malawi (Nyasa) Rift
The Study of Extension and maGmatism in Malawi aNd Tanzania (SEGMeNT) project acquired a comprehensive suite of geophysical and geochemical datasets across the northern Malawi (Nyasa) rift in the East Africa rift system. Onshore/offshore active and passive seismic data, long‐period and wideband magnetotelluric data, continuous Global Positioning System data, and geochemical samples were acquired bAuthorsDonna J. Shillington, J. B. Gaherty, Cynthia J. Ebinger, Christopher A. Scholz, Kate Selway, Andrew A. Nyblade, Paul A. Bedrosian, Cornelia Class, Scott Nooner, Matthew E. Pritchard, Julie L. Elliott, Patrick R. N. Chindandali, Gaby Mbogoni, Richard Wambura Ferdinand, Nelson Boniface, Shukrani Manya, Godson Kamihanda, Elifuraha Saria, Gabriel Mulibo, Jalf Salima, Abdul Mruma, Leonard Kalindekafe, Natalie J. Accardo, Ntambila Daud, Marsella Kachingwe, Gary T. Mesko, Tannis McCartney, Melania Maquay, J. P. O'Donnell, Gabrielle Tepp, Khalfan Mtelela, Per Trinhammer, Douglas Wood, Ernest Aaron, Mark Gibaud, Martin Rapa, Cathy Pfeifer, Felix Mphepo, Duncan Gondwe, Gabriella Arroyo, Celia EddyHighly conductive horizons in the Mesoproterozoic Belt-Purcell Basin: Sulfidic early basin strata as key markers of Cordilleran shortening and Eocene extension
We investigated the crustal structure of the central Mesoproterozoic Belt Basin in northwestern Montana and northern Idaho using a crustal resistivity section derived from a transect of new short- and long-period magnetotelluric (MT) stations. Two- and three-dimensional resistivity models were generated from these data in combination with data collected previously along three parallel short-periodAuthorsPaul A. Bedrosian, Stephen E. Box - Software
Below are software products associated with this project.
- News
Below are news stories associated with this project.
- Partners
In addition to the USGS Geomagnetism Program and the USGS Advanced Research Computing group, below are external partners associated with this project.