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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
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Improving gas-derived parameterization of groundwater using free phase gas measurements Improving gas-derived parameterization of groundwater using free phase gas measurements
Dissolved atmogenic gasses in groundwater provide significant information about recharge conditions, flowpath, and age. Free phase gas in aquifers is largely ignored in these analyses and there is a lack of quantitative analysis for gas flux mechanisms. Many related fields encountering multiphase flow acknowledge that the presence of bubbles allows for the rapid exsolution of dissolved...
Authors
Robert J Agnew, Andrew G. Hunt, Todd Halihan
The Geodetic Centroid (gCent) Catalog: Global earthquake monitoring with satellite imaging geodesy The Geodetic Centroid (gCent) Catalog: Global earthquake monitoring with satellite imaging geodesy
Remote sensing geodetic observations (Interferometric Synthetic Aperture Radar [InSAR] and optical correlation [“pixel tracking”]) serve an increasingly diverse and important role in earthquake monitoring and response. This study introduces the Geodetic Centroid (gCent) catalog—an earthquake catalog derived solely from space‐based geodetic observations—and analysis of 74 earthquakes (...
Authors
William D. Barnhart, Hannah N. Shea
Intra-site sources of restoration variability in severely invaded rangeland: Strong temporal effects of herbicide-weather interactions; weak spatial effects of plant-community patch type and litter Intra-site sources of restoration variability in severely invaded rangeland: Strong temporal effects of herbicide-weather interactions; weak spatial effects of plant-community patch type and litter
Invasions by exotic annual grasses (EAGs) are replacing native perennials in semiarid areas globally, including the vast sagebrush-steppe rangelands of western North America. Efforts to eradicate EAGs and restore perennials have had mixed success, especially in relatively warm and dry areas where EAGs had high dominance prior to intervention. Greater consideration of the ecological...
Authors
Rebecca Donaldson, Matthew J. Germino
In-reservoir physical processes modulate aqueous and biological methylmercury export from a seasonally anoxic reservoir In-reservoir physical processes modulate aqueous and biological methylmercury export from a seasonally anoxic reservoir
Anoxic conditions within reservoirs related to thermal stratification and oxygen depletion lead to methylmercury (MeHg) production, a key process governing the uptake of mercury in aquatic food webs. Once formed within a reservoir, the timing and magnitude of the biological uptake of MeHg and the relative importance of MeHg export in water versus biological compartments remain poorly...
Authors
Austin K. Baldwin, Collin A. Eagles-Smith, James Willacker, Brett Poulin, David P. Krabbenhoft, Jesse Naymik, Michael T. Tate, Dain Bates, Nick Gastelecutto, Charles Hoovestol, Christopher F. Larsen, Alysa Muir Yoder, James A. Chandler, Ralph Myers
Combining eddy covariance and chamber methods to better constrain CO2 and CH4 fluxes across a heterogeneous restored tidal wetland Combining eddy covariance and chamber methods to better constrain CO2 and CH4 fluxes across a heterogeneous restored tidal wetland
Tidal wetlands play an important role in global carbon cycling by storing carbon in sediment at millennial time scales, transporting dissolved carbon into coastal waters, and contributing significantly to global CH4 budgets. However, these ecosystems' greenhouse gas monitoring and predictions are challenging due to spatial heterogeneity and tidal flooding. We utilized eddy covariance and...
Authors
Julie Shahan, Housen Chu, Lisamarie Windham-Myers, Maiyah Matsumura, Joseph Carlin, Elke Eichelmann, Ellen J Goodrich-Stuart, Brian A. Bergamaschi, Kyle Kensuke Nakatsuka, Patty Oikawa, Cove Sturtevant
Evaluation of select velocity measurement techniques for estimating discharge in small streams across the United States Evaluation of select velocity measurement techniques for estimating discharge in small streams across the United States
Multiple instruments and methods exist for collecting discrete streamflow measurements in small streams with low flows, defined here as less than 5.7 m3/s (200 ft3/s). Included in the available methods are low-cost approaches that are infrequently used, in part, because their uncertainty is not well known. In this work, we evaluated the accuracy and suitability of three low-cost velocity
Authors
Tyler V. King, Stephen A. Hundt, Amy E. Simonson, Kyle W. Blasch
Mars Science Laboratory CheMin data from the Glen Torridon region and the significance of lake-groundwater interactions in interpreting mineralogy and sedimentary history Mars Science Laboratory CheMin data from the Glen Torridon region and the significance of lake-groundwater interactions in interpreting mineralogy and sedimentary history
The Glen Torridon (GT) region is positioned in terrains with strong clay mineral signatures, as inferred from orbital spectroscopy. The GT campaign confirmed orbital distinctions with in situ measurements by the Mars Science Laboratory rover, Curiosity, and the CheMin X-ray diffraction instrument with of some of the highest clay mineral abundances to date. Additionally, GT is unique...
Authors
Michael T. Thorpe, T. F. Bristow, E. Rampe, Nicholas Tosca, John P. Grotzinger, Kristen A. Bennett, C. N. Achilles, D. F. Blake, S. J. Chipera, G. Downs, R. T. Downs, S. M. Morrison, V. Tu, N. Castle, P. Craig, D. J. Des Marais, R. M. Hazen, D. W. Ming, R. V. Morris, A. H. Treiman, D. T. Vaniman, A. S. Yen, A. R. Vasavada, Erwin Dehouck, J. Bridges, J.O. Berger, Amy McAdam, T. Peretyazhko, K. Siebach, A. B. Bryk, V. F. Fox, Christopher M. Fedo
Quantifying flow and nonflow management impacts on an endangered fish by integrating data, research, and expert opinion Quantifying flow and nonflow management impacts on an endangered fish by integrating data, research, and expert opinion
Managers charged with recovering endangered species in regulated river segments often have limited flexibility to alter flow regimes and want estimates of the expected population benefits associated with both flow and nonflow management actions. Disentangling impacts on different life stages from concurrently applied actions is essential for determining the effectiveness of each action...
Authors
Charles B. Yackulic, Thomas P Archdeacon, Richard A. Valdez, Monika Hobbs, Michael D. Porter, Joel Lusk, Ashley M. Tanner, Eric J Gonzales, Debbie Y Lee, Grace M Haggerty
Biosafety practices when working with bats: A guide to field research considerations Biosafety practices when working with bats: A guide to field research considerations
Introduction: Field work with bats is an important contribution to many areas of research in environmental biology and ecology, as well as microbiology. Work with bats poses hazards such as bites and scratches, and the potential for exposure to infectious pathogens such as rabies virus. It also exposes researchers to many other potential hazards inherent to field work, such as...
Authors
Alvaro Aguilar-Setien, Nidia Arechiga-Ceballos, Gary A. Balsamo, Amy J. Behrman, Hannah K. Frank, Gary R. Fujimoto, Elizabeth Gilman Duane, Thomas Warner Hudson, Shelley M. Jones, Luis A. Ochoa Carrera, Gregory L. Powell, Carrie Alison Smith, Joni Triantis Van Sickle, Susan E. Vleck
Development of the LCMAP annual land cover product across Hawai'i Development of the LCMAP annual land cover product across Hawai'i
Following the completion of land cover and change (LCC) products for the conterminous United States (CONUS), the U.S. Geological Survey's (USGS’s) Land Change Monitoring, Assessment, and Projection initiative has broadened the capability of characterizing continuous historical land change across the full Landsat records for Hawaiʻi at 30-meter resolution. One of the challenges of...
Authors
Congcong Li, George Z. Xian, Danika F. Wellington, Kelcy Smith, Josephine Horton, Qiang Zhou
Viscoelastic fault-based model of crustal deformation for the 2023 update to the U.S. National Seismic Hazard Model Viscoelastic fault-based model of crustal deformation for the 2023 update to the U.S. National Seismic Hazard Model
The 2023 update to the National Seismic Hazard (NSHM) model is informed by several deformation models that furnish geodetically estimated fault slip rates. Here I describe a fault‐based model that permits estimation of long‐term slip rates on discrete faults and the distribution of off‐fault moment release. It is based on quantification of the earthquake cycle on a viscoelastic model of...
Authors
Frederick Pollitz
Improved method for simulating groundwater inundation using the MODFLOW 6 Lake Transport Package Improved method for simulating groundwater inundation using the MODFLOW 6 Lake Transport Package
Groundwater inundation due to sea level rise can affect island and coastal freshwater resources by exposing water tables to direct, continuous evaporation. Numerical simulations of groundwater inundation effects on coastal and island aquifers have been limited by an inability to simulate solute transport and variable density flow between the aquifer and lakes formed by groundwater...
Authors
Lauren K. Mancewicz, Alex Mayer, Christian D. Langevin, Jason Gulley