Anji Shah is a research geophysicist with the Geology, Geophysics, and Geochemistry Science Center in Denver, CO, specializing in the use of gravity, magnetic and radiometric methods for geologic characterization and interpretation.
She is currently working on several projects involving subsurface geologic characterization for earthquake hazard, mineral resource, and energy resource applications. She also has a background in marine geophysics.
For earthquake hazard studies, Dr. Shah uses gravity and magnetic data to distinguish contacts between subsurface rocks with different densities or magnetic properties. In some regions, these contacts may delineate buried faults and other structures that suggest seismic risk (see this article for application to the 2011 Mw5.8 Mineral, Virginia earthquake). Gravity and magnetic data can also be used to distinguish areas that may be more likely to exhibit seismicity in response to fluid injection (see this article for application to north-central Oklahoma).
Dr. Shah has also led several projects involving imaging and evaluation of rare-earth-element (REE) deposits. Concentrations of REE-bearing minerals in certain geological environments can be detected using radiometric and magnetic methods. Heavy mineral sands are of particular interest because their extraction involves minimal impact; REE-bearing monazite and xenotime have been observed throughout the southeastern U.S. The Eastern Adirondacks were mined in the 1800's and 1900's for magnetite. The ores also contain REE-bearing apatite, and often REE's are present in mining tailings. A combination of geophysical, geological and geochronological approaches is being used to study this area.
Professional Experience
Research Geophysicist, U.S. Geological Survey, 2007-present
Senior Research Scientist, Dynamics Technology, Inc. (now Raytheon Company), 2004-2007
National Research Council Postdoctoral Research Associate, Naval Research Laboratory, 2001-2004
Education and Certifications
Ph.D. Earth and Environmental Sciences, Columbia University, 2001
M.S. Oceanography, University of Washington, 1996
M.S. Applied Mathematics, New York University, 1990
B.S. Mathematics, Stony Brook University, 1988
Abstracts and Presentations
Shah, A., Walsh, G., Taylor, R., Taylor, C., Aleinikoff, J., Klein, A., Regan, S., and Lupulescu, M., 2016, Geophysical, geochemical, and geological approaches to evaluating rare earth resources in the Eastern Adirondacks, upstate New York, Geological Society of America 2016 Annual Meeting, doi: 10.1130/abs/2016AM-281761.
Boyd, O.S. and A. K. Shah, 2016, Progress on the USGS National Crustal Model for seismic hazard studies, Seismological Society of America Annual Meeting, 2016.
Shah, A., R. Stanley, K.A. Lewis, P.J. Haeussler, C.J. Potter, R.W. Saltus and J. Phillips, 2015, Aeromagnetic survey data used to map features of the Cook Inlet and Susitna basins, Alaska, AGU-SEG Workshop "Potential field and electromagnetic methods applied to basin studies," 2015.
Pratt, T., A. Shah, and J.W. Horton, 2014, Discerning Faults Responsible for the Charleston, SC earthquake of 1886, Seismological Society of America Annual Meeting, 2014.
Science and Products
Critical Mineral Resources in Heavy Mineral Sands of the U.S. Atlantic Coastal Plain
Mineville, Eastern Adirondacks – Geophysical and Geologic Studies
Geophysical and Geochemical Approaches to Evaluating Rare Earth Element (REE) Potential in the Southeastern U.S.
Airborne magnetic and radiometric survey, Virginia and North Carolina Fall Zone, 2021
Airborne magnetic and radiometric survey, Munsungun region in northern Maine, 2021
Ground-based gamma spectrometry data collected in northern Maine (Version 2.0, September 2022)
Airborne magnetic and radiometric survey, Columbia, South Carolina and surrounds, 2020
Digital geologic map of the Elizabethtown Quadrangle, Essex County, New York
Airborne Geophysical Survey Inventory of the Conterminous United States, Alaska, Hawaii, and Puerto Rico (ver. 3.0, November 2021)
Airborne magnetic and radiometric survey, Charleston, South Carolina and surrounds, 2019
Digital datasets documenting subsurface data locations, topographic metrics, fault scarp mapping, and revised fault network for Crowley's Ridge, New Madrid Seismic Zone
Principal facts of gravity data collected in and around the eastern Adirondack highlands, northern New York
Airborne Magnetic Surveys over Oklahoma, 2017
Petrophysical data collected on outcrops and rock samples from the eastern Adirondack Highlands, New York
GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
Focus areas for data acquisition for potential domestic resources of 11 critical minerals in the conterminous United States, Hawaii, and Puerto Rico—Aluminum, cobalt, graphite, lithium, niobium, platinum-group elements, rare earth elements, tantalum, tin,
Focus areas for data acquisition for potential domestic resources of 13 critical minerals in the conterminous United States and Puerto Rico — Antimony, barite, beryllium, chromium, fluorspar, hafnium, helium, magnesium, manganese, potash, uranium, vanadiu
Mapping critical minerals from the sky
Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York
Three-dimensional shape and structure of the Susitna basin, south-central Alaska, from geophysical data
Evidence for late Quaternary deformation along Crowley's Ridge, New Madrid seismic zone
The US Geological Survey’s Earth Mapping Resources Initiative (Earth MRI)—Providing framework geologic, geophysical, and elevation data to the nation’s critical mineral-bearing regions
Geochemistry and geophysics of iron oxide-apatite deposits and associated waste piles with implications for potential rare earth element resources from ore and historic mine waste in the eastern Adirondack Highlands, New York, USA
Depth to basement and thickness of unconsolidated sediments for the western United States—Initial estimates for layers of the U.S. Geological Survey National Crustal Model
Aeromagnetic data reveal potentially seismogenic basement faults in the induced seismicity setting of Oklahoma
Assessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017
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
- Science
Critical Mineral Resources in Heavy Mineral Sands of the U.S. Atlantic Coastal Plain
In many parts of the southeastern U.S., dark-colored sands can be seen at beaches or beneath soil. These sands contain titanium, zirconium, and rare earth elements, which are considered critical mineral resources. Such sands are present in areas from the coast to a hundred miles or more inland beneath soil within the Atlantic Coastal Plain Province. In some locales they are concentrated enough to...Mineville, Eastern Adirondacks – Geophysical and Geologic Studies
The USGS is using a set of advanced imaging and analysis tools to study the rocks within the eastern Adirondacks of upstate New York. The goal of these studies is to gain a better understanding of the geology and mineral resources in the area.Geophysical and Geochemical Approaches to Evaluating Rare Earth Element (REE) Potential in the Southeastern U.S.
Rare-earth elements (REE) are an essential component of numerous advanced technology applications including high efficiency batteries, emerging energy technologies, and key defense systems. The goal of this study was to assist in the evaluation of the distribution of rare earth element deposits in the southeastern U.S., with a focus on sediment-hosted resources. - Data
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Airborne magnetic and radiometric survey, Virginia and North Carolina Fall Zone, 2021
This data release provides digital flight line data for a high-resolution airborne magnetic and radiometric survey over Virginia and North Carolina along and near the eastern U.S. 'Fall Zone', which represents the transitional area between Atlantic Coastal Plain sediments and Piedmont metamorphic and igneous rocks. The airborne data collection was funded by the U.S. Geological Survey (USGS) EarthAirborne magnetic and radiometric survey, Munsungun region in northern Maine, 2021
This data release provides digital flight line data for a high-resolution airborne magnetic and radiometric survey over parts of northern Maine. The airborne data collection was funded by the U.S. Geological Survey (USGS) Earth Mapping Resource Initiative (Earth MRI) with goals of better understanding volcanogenic massive sulfide mineral deposits, sediment hosted manganese deposits, and their surrGround-based gamma spectrometry data collected in northern Maine (Version 2.0, September 2022)
Radiometric (gamma spectrometry) measurements were made during walking surveys in northern Maine using a GF Instruments Gamma Surveyor. These surveys involved recording measurement averages over 30-second intervals while holding the instrument approximately 1 meter above the ground. Locations were obtained via a handheld GPS. Data were collected over and in the vicinity of a radiometric thorium anAirborne magnetic and radiometric survey, Columbia, South Carolina and surrounds, 2020
This data release provides digital flight line data for a high-resolution airborne magnetic and radiometric survey over Columbia, South Carolina, and the surrounding region. The airborne data collection was funded by the U.S. Geological Survey (USGS) Earth Mapping Resource Initiative (Earth MRI) with goals of better understanding placer deposits containing critical mineral resources titanium, zircDigital geologic map of the Elizabethtown Quadrangle, Essex County, New York
This website provides digitized shapefiles representing surface geologic features depicted in Matthew S. Walton's unpublished 1960 geologic map of the Elizabethtown quadrangle, Essex County, New York. Features represented by these files include geologic units representing Precambrian basement rock, geologic structures, diabase dikes, mine shaft locations, and water bodies. The shape files in thisAirborne Geophysical Survey Inventory of the Conterminous United States, Alaska, Hawaii, and Puerto Rico (ver. 3.0, November 2021)
This data release is a compilation of the locations of airborne geophysical surveys in the United States. The inventory documents public airborne geophysical surveys primarily flown by or contracted by the USGS from 1943 to present. In addition, surveys from the State of Alaska, Department of Natural Resources, Division of Geological and Geophysical Surveys (DGGS): Airborne GeophysWeb, the BureauAirborne magnetic and radiometric survey, Charleston, South Carolina and surrounds, 2019
This data release provides digital flight line data for a high-resolution airborne magnetic and radiometric survey over Charleston, South Carolina and the surrounding region. These data were collected to better understand earthquake hazards in the Charleston seismic zone by imaging structural features in the crystalline basement and to image heavy mineral sands containing titanium, zirconium, andDigital datasets documenting subsurface data locations, topographic metrics, fault scarp mapping, and revised fault network for Crowley's Ridge, New Madrid Seismic Zone
This release provides the data and interpretations supporting evidence of late Quaternary faulting along Crowleys Ridge in the New Madrid seismic zone. The release includes location information for seismic reflection and airborne electromagnetic (AEM) data over Crowleys Ridge, a table of topographic metrics derived from analysis of the 10m National Elevation Dataset (NED) digital elevation model (Principal facts of gravity data collected in and around the eastern Adirondack highlands, northern New York
Gravity data were collected in 2016 and 2017 to assist in mapping subsurface geology in and around the eastern Adirondack highlands, northern New York, which host numerous iron-oxide apatite deposits. Many of these deposits contain rare-earth elements, which are considered a critical mineral resource. This data release provides principal facts for 189 new gravity stations that were acquired to filAirborne Magnetic Surveys over Oklahoma, 2017
Airborne magnetic surveys were conducted in Oklahoma from August 11th, 2017-October 28th, 2017, by Goldak Airborne Surveys. Here we present downloadable flight line data from those surveys in comma-separated values (csv format). Three areas were flown along a draped surface with a nominal survey height above ground of 120 meters. The flight line spacing for these areas was 200 to 400 m for Area 12Petrophysical data collected on outcrops and rock samples from the eastern Adirondack Highlands, New York
Petrophysical data were collected in the eastern Adirondack Highlands during several field campaigns in 2016-2017. This data release provides magnetic susceptibility, gamma spectrometry, and density measurements on rock outcrops, hand samples, and during walking surveys. Rock types for the outcrops and samples were identified using standard field methods. Locations of the outcrops or samples wereGIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS Earth Mappi - Multimedia
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Focus areas for data acquisition for potential domestic resources of 11 critical minerals in the conterminous United States, Hawaii, and Puerto Rico—Aluminum, cobalt, graphite, lithium, niobium, platinum-group elements, rare earth elements, tantalum, tin,
In response to a need for information on potential domestic sources of critical minerals, the Earth Mapping Resources Initiative (Earth MRI) was established to identify and prioritize areas for acquisition of new geologic mapping, geophysical data, and elevation data to improve our knowledge of the geologic framework of the United States. Phase 1 of Earth MRI concentrated on those geologic terraneFocus areas for data acquisition for potential domestic resources of 13 critical minerals in the conterminous United States and Puerto Rico — Antimony, barite, beryllium, chromium, fluorspar, hafnium, helium, magnesium, manganese, potash, uranium, vanadiu
The Earth Mapping Resources Initiative (Earth MRI) is conducted in phases to identify areas for acquiring new geologic framework data to identify potential domestic resources of the 35 mineral materials designated as critical minerals for the United States. This report describes the data sources and summary results for 13 critical minerals evaluated in the conterminous United States and Puerto RicMapping critical minerals from the sky
Critical mineral resources titanium, zirconium, and rare earth elements occur in placer deposits over vast parts of the U.S. Atlantic Coastal Plain. Key questions regarding provenance, pathways of minerals to deposit sites, and relations to geologic features remain unexplained. As part of a national effort to collect data over regions prospective for critical minerals, the first public high-resoluIntegrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York
The eastern Adirondack Highlands of northern New York host dozens of iron oxide-apatite (IOA) deposits containing magnetite and rare earth element (REE)-bearing apatite. We use new aeromagnetic, aeroradiometric, ground gravity, and sample petrophysical and geochemical data to image and understand these deposits and their geologic framework. Aeromagnetic total field data reflect highly magnetic leuThree-dimensional shape and structure of the Susitna basin, south-central Alaska, from geophysical data
We use gravity, magnetic, seismic reflection, well, and outcrop data to determine the three-dimensional shape and structural features of south-central Alaska’s Susitna basin. This basin is located within the Aleutian-Alaskan convergent margin region and is expected to show effects of regional subduction zone processes. Aeromagnetic data, when filtered to highlight anomalies associated with sourcesEvidence for late Quaternary deformation along Crowley's Ridge, New Madrid seismic zone
The New Madrid seismic zone has been the source of multiple major (M ~7.0–7.5) earthquakes in the past 2 ka, yet the surface expression of recent deformation remains ambiguous. Crowleys Ridge, a linear ridge trending north‐south for 300+ km through the Mississippi Embayment, has been interpreted as either a fault‐bounded uplift or a nontectonic erosional remnant. New and previously published seismThe US Geological Survey’s Earth Mapping Resources Initiative (Earth MRI)—Providing framework geologic, geophysical, and elevation data to the nation’s critical mineral-bearing regions
New detailed mapping of the geologic resources of the Nation has the potential to significantly close the gap in the essential data needed to fuel a modern era of economic development and technological innovation, while at the same time dramatically enhancing our understanding of the fundamental way geology impacts everyday life, from the domestic critical mineral resources that are necessary forGeochemistry and geophysics of iron oxide-apatite deposits and associated waste piles with implications for potential rare earth element resources from ore and historic mine waste in the eastern Adirondack Highlands, New York, USA
The iron oxide-apatite (IOA) deposits of the eastern Adirondack Highlands, New York, are historical high-grade magnetite mines that contain variable concentrations of rare earth element (REE)-bearing apatite crystals. The majority of the deposits are hosted within sodically altered Lyon Mountain granite gneiss, although some deposits occur within paragneiss, gabbro, anorthosite, or potassically alDepth to basement and thickness of unconsolidated sediments for the western United States—Initial estimates for layers of the U.S. Geological Survey National Crustal Model
We present numeric grids containing estimates of the thickness of unconsolidated sediments and depth to the pre-Cenozoicbasement for the western United States. Values for these grids were combined and integrated from previous studies or deriveddirectly from gravity analyses. The grids are provided with 1-kilometer grid-node spacing in ScienceBase (https://www.sciencebase.gov).These layers may be uAeromagnetic data reveal potentially seismogenic basement faults in the induced seismicity setting of Oklahoma
New aeromagnetic survey data collected over north central Oklahoma image possible seismogenic faults in the crystalline basement. Linear earthquake sequences associated with induced seismicity suggest the reactivation of ancient basement faults, but few of these sequences are aligned with mapped faults. The new data show many earthquake sequences aligned with linear magnetic gradients or offsets bAssessment of undiscovered oil and gas resources of the Susitna Basin, southern Alaska, 2017
The U.S. Geological Survey (USGS) recently completed an assessment of undiscovered, technically recoverable oil and gas resources in the Susitna Basin of southern Alaska. Using a geology-based methodology, the USGS estimates that mean undiscovered volumes of about 2 million barrels of oil and nearly 1.7 trillion cubic feet of gas may be found in this area.Non-USGS Publications**
Shah, A. and W. R. Buck, 2006, The rise and fall of axial highs at ridge jumps: Journal of Geophysical Research, 111, B08101, https://doi.org/10.1029/2005JB003657.Shah, A., M.-H. Cormier, W. F. Ryan, W. Jin, J. Sinton, E. Bergmanis, J. Carlut, A. Bradley and D. Yoerger, 2003, Episodic dike swarms inferred from near-bottom magnetic anomaly maps at the southern East Pacific Rise: Journal of Geophysical Research, 108 (B2), 2097, https://doi.org/10.1029/2001JB000564.Shah, A. and W. R. Buck, 2003, Plate bending stresses at axial highs and implications for faulting behavior, Earth and Planetary Science Letters, 211 (3-4), 343-356, https://doi.org/10.1016/S0012-821X(03)00187-0.Cormier, M.-H., W. B. Ryan, A. Shah, W. Jin, A. M. Bradley, D. Yoerger, 2003, Waxing and waning volcanism along the East Pacific Rise on the millennium timescale: Geology, 31 (7), 633-636, https://doi.org/10.1130/0091-7613(2003)031<0633:WAWVAT>2.0.CO;2.Shah, A. and W. R. Buck, 2001, Causes for axial high topography at mid-ocean ridges and the role of crustal thermal structure, Journal of Geophysical Research, 106 (B12), 30865-30879, https://doi.org/10.1029/2000JB000079.Shah, A. and J.-C. Sempéré, 1998, Morphology of the transition from an axial high to a rift valley at the Southeast Indian Ridge, and the relation to variations in mantle temperature: Journal of Geophysical Research,103 (B3), 5203-5223, https://doi.org/10.1029/97JB03110.Géli, L., H. Bougalt, D. Aslanian, A. Briais, L. Dosso, J. Etoubleau, J.-P. LeFormal, M. Maia, H. Ondréas, J.-L. Olivet, C. Richardson, K. Sayanagi, N. Seama, A. Shah, I. Vlastelic, and M. Yamamoto, 1997, Evolution of the Pacific-Antarctic Ridge South of the Udintsev Fracture Zone: Science, 278 (5341), 1281-1284, https://doi.org/10.1126/science.278.5341.1281.Goff, J. A., Y. Ma, A. Shah, J. R. Cochran, and J.-C. Sempéré, 1996, Stochastic analysis of seafloor morphology on the flanks of the Southeast Indian Ridge: The influence of ridge morphology on the formation of abyssal hills: Journal of Geophysical Research, 102 (B7), 15521-15534, https://doi.org/10.1029/97JB00781.**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.
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