Reports
Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 82,000 reports authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
Filter Total Items: 85226
Improving offshore 3D splay fault geometries and slip histories using seismic data reprocessing and structural modeling Improving offshore 3D splay fault geometries and slip histories using seismic data reprocessing and structural modeling
The goal of this project as written in the CRESCENT seed grant proposal was as follows: 1) reprocess selected profiles along strike from 45° to 48°N from the CASIE21 crustal-scale seismic data to obtain higher-resolution and higher-quality imaging of the uppermost 1-2 km of the accretionary wedge; 2) convert high-resolution USGS sparker seismic data from the time to depth domain to...
Authors
Anna M. Ledeczi, Nathaniel C. Miller, Harold J. Tobin, Cailey B. Condit
Range-wide relative abundance of the Appalachian grizzled skipper (Pyrgus centaureae wyandot) in the Eastern United States Range-wide relative abundance of the Appalachian grizzled skipper (Pyrgus centaureae wyandot) in the Eastern United States
The U.S. Fish and Wildlife Service has designated the Pyrgus centaureae wyandot (Appalachian Grizzled Skipper [AGS]) to be at-risk, based on its declining populations and the lack of information on its status. The objective of this study was to complete range-wide surveys to locate extant AGS colonies and to quantify the number of AGS observed at each location. From 2021–24, 284 surveys...
Authors
Nimish B. Vyas, Jennifer Selfridge, David Cuthrell, Robert Somes, Erin White, Judith Ratcliffe, J. Merrill Lynch, Laurie Hamon, Eileen Wyza, Betsy Leppo, Pete Woods, Anthony Tur, Donovan Drummey, Kathryn Nolan, Ellison Orcutt, Andrew Rapp, Leah Card, Jakob Goldner, Susan Olcott
Status and trends of pelagic and benthic prey fish populations in Lake Michigan, 2025 Status and trends of pelagic and benthic prey fish populations in Lake Michigan, 2025
Fall bottom trawl (fall BT) and lakewide acoustic (AC) surveys are conducted annually to generate indices of pelagic and benthic prey fish densities in Lake Michigan. The fall BT survey has been conducted each fall since 1973 using 12-m trawls at depths ranging from 9 to 110 m at fixed locations distributed across seven transects; this survey estimates densities of seven prey fish...
Authors
Ralph W. Tingley, Timothy P. O’Brien, Charles P. Madenjian, Peter C. Esselman, Patricia M. Dieter, Kristy R. Phillips, Ben Turschak, Dale Hanson, Steven A. Farha
Continuous and high-resolution longitudinal profiles of the water surface and riverbed elevation for 282 miles of the Colorado River from Lees Ferry to Pearce Ferry, Arizona, 2021 Continuous and high-resolution longitudinal profiles of the water surface and riverbed elevation for 282 miles of the Colorado River from Lees Ferry to Pearce Ferry, Arizona, 2021
Longitudinal profiles of water surface and riverbed elevations capture key geomorphic characteristics that can be affected by water infrastructure and natural processes. Continuous water surface profiles of the Colorado River in Grand Canyon, a river influenced by two of the largest dams in the United States, have been measured infrequently. The water surface profile was first measured...
Authors
Shannon L. Sartain, Matthew A. Kaplinski, Keith Kohl, Katherine A. Chapman, Nathaniel D. Bransky, Joel B. Sankey, Paul E. Grams
High-resolution transboundary vegetation community maps of the Sonoran and Mojave Desert ecoregion to support critical landscape conservation planning and habitat management needs High-resolution transboundary vegetation community maps of the Sonoran and Mojave Desert ecoregion to support critical landscape conservation planning and habitat management needs
We produced a 30-m resolution binational land cover map of Bird Conservation Region 33 (BCR 33) for the U.S. North American Bird Conservation Initiative. The region covers large portions of the Sonoran and Mojave Deserts. The map can support the U.S. Fish and Wildlife Service (FWS) Migratory Bird Program’s recovery planning efforts and constitutes the first known binational land cover...
Authors
Pamela L Nagler, Jennie N. Duberstein, James Broska, Kamel Didan, Myles B. Traphagen
Critical minerals memory match game Critical minerals memory match game
An educational information packet about the 2025 List of Critical Minerals, which includes a memory match game about select critical minerals and how they are used.
Authors
Danielle A. Olinger
The Great Lakes Geologic Mapping Coalition—Working collaboratively to understand the geology of the Great Lakes Region The Great Lakes Geologic Mapping Coalition—Working collaboratively to understand the geology of the Great Lakes Region
Introduction The Great Lakes Geologic Mapping Coalition (GLGMC), commonly referred to as the “Coalition,” is a partnership between the U.S. Geological Survey (USGS), the U.S. States of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin and the Canadian province of Ontario. The member States receive funding for geologic mapping work from the USGS National
Authors
Brianna Lopez, Jenna L. Shelton, Michael Marketti, Kate Ritzel, Brandon L. Graham
Assessment of undiscovered conventional oil and gas resources in the Berkine, Illizi, Hamra, Murzuq, and Erdis Kufra Basins of northern Africa, 2026 Assessment of undiscovered conventional oil and gas resources in the Berkine, Illizi, Hamra, Murzuq, and Erdis Kufra Basins of northern Africa, 2026
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 419 million barrels of oil and 5.5 trillion cubic feet of gas in the Berkine, Illizi, Hamra, Murzuq, and Erdis Kufra Basins of northern Africa.
Authors
Christopher J. Schenk, Tracey J. Mercier, Cheryl A. Woodall, Thomas M. Finn, Heidi M. Leathers-Miller, Michael E. Brownfield, Phuong A. Le, Stephanie B. Gaswirth, Marilyn E. Tennyson
Factors affecting benthic macroinvertebrate health in the City of Roanoke, Virginia, 2020–2023 Factors affecting benthic macroinvertebrate health in the City of Roanoke, Virginia, 2020–2023
Major waterways in the City of Roanoke (City) have failed to meet Virginia’s aquatic life designated use since 1996. Segments of the upper Roanoke River lack healthy benthic macroinvertebrate communities which prompted a total maximum daily load (TMDL) study by the Virginia Department of Environmental Quality (VDEQ) to identify the most probable stressor(s) causing the impairment. Excess...
Authors
Samuel Adam Miller, Marcus F Aguilar, Logan Helsley, Sally Entrekin
Methodology for construction of a three-layer geologic model of the conterminous United States using land surface, top of bedrock, and top of basement Methodology for construction of a three-layer geologic model of the conterminous United States using land surface, top of bedrock, and top of basement
This report describes the methodology used for the construction of a digital three-layer geologic model of the conterminous United States by mapping the altitude of three surfaces: land surface, the top of bedrock, and the top of basement. These surfaces are mapped through the compilation and synthesis of published stratigraphic horizons from numerous topical studies. The mapped surfaces...
Authors
Donald S. Sweetkind
Status and understanding of groundwater quality in the San Joaquin Valley Kern County subbasin domestic-supply aquifer study unit, 2022—California GAMA Priority Basin Project Status and understanding of groundwater quality in the San Joaquin Valley Kern County subbasin domestic-supply aquifer study unit, 2022—California GAMA Priority Basin Project
The quality of water accessed by domestic wells (here referred to as domestic groundwater resources) in the San Joaquin Valley Kern County subbasin (basin number 5-022.14) was assessed as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project (GAMA-PBP), in cooperation with the California State Water Resources Control Board. Kern County...
Authors
Jennifer S. Harkness, Kirsten E. Faulkner, Bryant C. Jurgens
Precipitation-based flood-inundation maps for the East Fork Little Blue River and tributaries at Lee’s Summit, Missouri, 2024 Precipitation-based flood-inundation maps for the East Fork Little Blue River and tributaries at Lee’s Summit, Missouri, 2024
The U.S. Geological Survey, in cooperation with the City of Lee’s Summit, Missouri, assessed flooding of the East Fork Little Blue River and tributaries for varying precipitation magnitudes and durations, varying antecedent runoff conditions, and projected climate-change conditions. The precipitation scenarios were used to develop a library of flood-inundation maps for a 2.95-mile reach...
Authors
Allison A. Atkinson