Skip to main content
U.S. flag

An official website of the United States government

Todd Hoefen

Todd Hoefen is a Geophysicist with the Geology, Geophysics, and Geochemistry Science Center.

Science and Products

link
Collage of airborne spectroscopy imagery

Spectroscopy and Hyperspectral Imaging of Critical Mineral Resources

Our project will characterize the primary critical minerals (minerals that contain critical elements in their base structure) that are not yet in the USGS Spectral Library. We propose to increase understanding of the spectral indicators of critical minerals using lab-based studies of hand specimens and drill core, hyperspectral field scanning, and hyperspectral images collected from aircraft.
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab
link

Spectroscopy and Hyperspectral Imaging of Critical Mineral Resources

Our project will characterize the primary critical minerals (minerals that contain critical elements in their base structure) that are not yet in the USGS Spectral Library. We propose to increase understanding of the spectral indicators of critical minerals using lab-based studies of hand specimens and drill core, hyperspectral field scanning, and hyperspectral images collected from aircraft.
Learn More
link
Hyperspectral camera measures output from calibration lamp

Development and Validation of Hyperspectral Imager for Field and Lab Scanning

The Mineral Resources Program has advanced methods of imaging spectroscopy (hyperspectral remote sensing) that are now used routinely by the earth science and remote sensing communities for mineral mapping, soil quality mapping, hazard mitigation, and other terrestrial and planetary applications. The USGS is highly qualified to advance this technology based on its world class expertise in mineral...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab
link

Development and Validation of Hyperspectral Imager for Field and Lab Scanning

The Mineral Resources Program has advanced methods of imaging spectroscopy (hyperspectral remote sensing) that are now used routinely by the earth science and remote sensing communities for mineral mapping, soil quality mapping, hazard mitigation, and other terrestrial and planetary applications. The USGS is highly qualified to advance this technology based on its world class expertise in mineral...
Learn More
link
spectral library example

USGS High Resolution Spectral Library

The USGS Spectral Library contains reflectance spectra, including samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, plants, vegetation communities, microorganisms, and man-made materials. The samples and spectra collected were assembled for the purpose of using spectral features for the remote detection of these and similar materials. The latest...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab
link

USGS High Resolution Spectral Library

The USGS Spectral Library contains reflectance spectra, including samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, plants, vegetation communities, microorganisms, and man-made materials. The samples and spectra collected were assembled for the purpose of using spectral features for the remote detection of these and similar materials. The latest...
Learn More
link
Hyperspectral images after the World Trade Center Twin Towers collapse

Environmental Studies of the World Trade Center Area After the September 11, 2001 Attack

USGS scientists conducted a remote sensing and mineralogical characterization study of lower Manhattan around the WTC after the September 11, 2001 attack.
By
Geology, Geophysics, and Geochemistry Science Center, Denver Microbeam Laboratory, Spectroscopy Lab
link

Environmental Studies of the World Trade Center Area After the September 11, 2001 Attack

USGS scientists conducted a remote sensing and mineralogical characterization study of lower Manhattan around the WTC after the September 11, 2001 attack.
Learn More

Spectroscopy of Expanded Vermiculite Products and Insulation

This dataset contains descriptions and analytical data (i.e., electron microprobe, X-ray diffraction, spectral reflectance, and scanning electron microprobe analyses) for unexpanded and expanded vermiculite samples. These data are provided for 52 samples of vermiculite attic insulation, horticultural products, aggregate, and packing materials derived from mines near Enoree, South Carolina; Libby,
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Denver Microbeam Laboratory, Spectroscopy Lab

Corescan Hyperspectral Core Imager, Mark III system data collected for the characterization of mineral resources near Nabesna, Alaska, 2014-2016

Corescan Hyperspectral Core Imager Mark III (HCI-III) system data were acquired for hand samples, and subsequent billets made from the hand samples, collected during the U.S. Geological Survey (USGS) 2014, 2015, and 2016 field seasons in the Nabesna area of the eastern Alaska Range. This area contains exposed porphyry deposits and hand samples were collected throughout the region in support of the
By
Geology, Geophysics, and Geochemistry Science Center

Imaging spectrometer reflectance data, mineral predominance map, and white mica wavelength position map, Nabesna Quadrangle, Alaska

Approximately 1,900 square kilometers of imagery were collected from July 14 to July 21, 2014 using a HyMap sensor (Cocks and others, 1998) mounted on a modified Piper Navajo aircraft. The survey area covered parts of the Wrangell and Nutzotin Mountains in the eastern Alaska Range near Nabesna, Alaska. The aircraft was flown at an altitude of approximately 5,050 meters (m) (3,480 m above the mean
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Whole rock, soil, sediment, x-ray diffraction, and electron microprobe analyses of samples from the Orange Hill-Bond Creek area, Nabesna Quadrangle, Alaska

This data release includes geochemical, x-ray diffraction mineralogical, and electron probe microanalysis (EPMA) data on rocks, soils, and sediments collected near the Orange Hill and Bond Creek porphyry copper deposits, Nabesna quadrangle, Alaska. Geochemical analyses were completed by a laboratory under contract with the U.S. Geological Survey (USGS). Electron microprobe and x-ray diffraction mi
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Denver Microbeam Laboratory, Spectroscopy Lab

Airborne imaging spectrometer data collected for characterizing mineral resources near Nabesna, Alaska, 2014

Imaging spectrometer (hyperspectral) data were collected using the HyMap sensor over the Nabesna Area of Interest (AOI) in the eastern Alaska Range, July 14 and July 21, 2014. The primary study area was a remote part of the eastern Alaska Range where porphyry deposits are exposed. The HyMap imaging spectrometer measured reflected sunlight in 126 narrow channels spanning the 0.4 to 2.5 micron wavel
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

USGS Spectral Library Version 7 Data

This data release provides the U.S. Geological Survey (USGS) Spectral Library Version 7 and all related documents. The library contains spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns). Laboratory samples of specific minerals, plants, chemical compounds, and man-made materials w
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link
link
Very high-resolution thermal infrared image shows the temperature of the fire line.
link
DJI S1000 UAS with a “Kolibri” sensor
link
DJI S1000 UAS flying into smoke plume
link
Prescribed Burn at Tall Timbers Research Station
link
Image shows a side-by-side view of plywood and its spectral signature
link
Image shows a side-by-side view of plywood and its spectral signature
link
Filter Total Items: 109

Imaging spectroscopy for the detection, assessment and monitoring of natural and anthropogenic hazards

Natural and anthropogenic hazards have the potential to impact all aspects of society including its economy and the environment. Diagnostic data to inform decision-making are critical for hazard management whether for emergency response, routine monitoring or assessments of potential risks. Imaging spectroscopy (IS) has unique contributions to make via the ability to provide some key quantitative
By
Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Multiscale hyperspectral imaging of the Orange Hill Porphyry Copper Deposit, Alaska, USA, with laboratory-, field-, and aircraft-based imaging spectrometers

In the past decade, use of hyperspectral imaging (imaging spectroscopy) for mineral exploration and mining operations has been increasing at different spatial scales. In this paper, we focus on recent trends in applying imaging spectrometer data to: 1) airborne imaging of high latitude deposits, 2) field-based imaging of outcrops, and 3) laboratory-level imaging of geologic samples. Comparing mine
By
Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Characterizing the source of potentially asbestos-bearing commercial vermiculite insulation using in situ IR spectroscopy

Commercially produced vermiculite insulation from Libby, Montana, contains trace levels of asbestiform amphibole, which is known to cause asbestos-related diseases. When vermiculite insulation is found in a building, evaluation for its potential asbestos content traditionally involves collecting a sample from an attic or wall and submitting it for time-consuming analyses at an off-site laboratory.
By
Geology, Geophysics, and Geochemistry Science Center, Denver Microbeam Laboratory, Spectroscopy Lab

USGS Spectral Library Version 7

We have assembled a library of spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns [μm]). Laboratory samples of specific minerals, plants, chemical compounds, and manmade materials were measured. In many cases, samples were purified, so that unique spectral features of a material ca
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Denver Microbeam Laboratory, Spectroscopy Lab

Environmental implications of the use of sulfidic back-bay sediments for dune reconstruction — Lessons learned post Hurricane Sandy

Some barrier-island dunes damaged or destroyed by Hurricane Sandy's storm surges in October 2012 have been reconstructed using sediments dredged from back bays. These sand-, clay-, and iron sulfide-rich sediments were used to make berm-like cores for the reconstructed dunes, which were then covered by beach sand. In November 2013, we sampled and analyzed partially weathered materials collected fro
By
Ecosystems, Toxic Substances Hydrology, Environmental Health Program, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Hyperspectral surveying for mineral resources in Alaska

Alaska is a major producer of base and precious metals and has a high potential for additional undiscovered mineral resources. However, discovery is hindered by Alaska’s vast size, remoteness, and rugged terrain. New methods are needed to overcome these obstacles in order to fully evaluate Alaska’s geology and mineral resource potential. Hyperspectral surveying is one method that can be used to ra
By
Energy and Minerals, Mineral Resources Program, Geology, Energy & Minerals Science Center, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Trace elements in stormflow, ash, and burned soil following the 2009 station fire in southern California

Most research on the effects of wildfires on stream water quality has focused on suspended sediment and nutrients in streams and water bodies, and relatively little research has examined the effects of wildfires on trace elements. The purpose of this study was two-fold: 1) to determine the effect of the 2009 Station Fire in the Angeles National Forest northeast of Los Angeles, CA on trace element
By
Water Resources, Mineral Resources Program, California Water Science Center, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Mapping surficial minerals at high latitudes: The USGS 2014 imaging spectrometer data collection in Alaska

Passive optical remote sensing of high latitude regions faces many challenges including a short acquisition season and poor illumination due to low solar elevation. Additional complications are encountered in the identification of surface minerals for mineral resource characterization because minerals of interest commonly are exposed on steep terrain, further challenging reflectance retrieval and
By
Mineral Resources Program, Geology, Energy & Minerals Science Center, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

The environmental and medical geochemistry of potentially hazardous materials produced by disasters

Many natural or human-caused disasters release potentially hazardous materials (HM) that may pose threats to the environment and health of exposed humans, wildlife, and livestock. This chapter summarizes the environmentally and toxicologically significant physical, mineralogical, and geochemical characteristics of materials produced by a wide variety of recent disasters, such as volcanic eruptions
By
Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Spectroscopy Lab

Deposit model for heavy-mineral sands in coastal environments

This report provides a descriptive model of heavy-mineral sands, which are sedimentary deposits of dense minerals that accumulate with sand, silt, and clay in coastal environments, locally forming economic concentrations of the heavy minerals. This deposit type is the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, through recovery of the minerals ilmenite (Fe2
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Asphaltene content and composition as a measure of Deepwater Horizon oil spill losses within the first 80 days

The composition and content of asphaltenes in spilled and original wellhead oils from the Deepwater Horizon (DWH) incident provide information on the amount of original oil lost and the processes most responsible for the losses within the first 80 days of the active spill. Spilled oils were collected from open waters, coastal waters and coastal sediments during the incident. Asphaltenes are the mo
By
Energy Resources Program, Central Energy Resources Science Center, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

Hyperspectral surface materials map of quadrangle 3466, La`l wa Sar Jangal (507) and Bamyan (508) quadrangles, Afghanistan, showing carbonates, phyllosilicates, sulfates, altered minerals, and other materials

This map shows the spatial distribution of selected carbonates, phyllosilicates, sulfates, altered minerals, and other materials derived from analysis of airborne HyMap™ imaging spectrometer (hyperspectral) data of Afghanistan collected in late 2007. The map is one in a series of U.S. Geological Survey/Afghanistan Geological Survey quadrangle maps covering Afghanistan. Flown at an altitude of 50,
By
Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab

USGS Digital Spectral Library

References for material identification in remote sensing images. The library contains spectral reflectance data for of hundreds of materials, including minerals, vegetation, organic and volatile compounds, and man-made materials.

By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Spectroscopy Lab
link

Igniting a New Trend in Public Safety

U.S. Geological Survey scientists and partners are taking technology to the next level, using unmanned aircraft systems (UAS), commonly called drones...

Read Article
link

USGS Spectral Library gets Ultra- and Hyper- Revamp

We've got a library full of spectral signatures, like a police fingerprint library for minerals and other substances!

Read Article

Science and Products