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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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Higher temperature sensitivity of flowering than leaf-out alters the time between phenophases across temperate tree species Higher temperature sensitivity of flowering than leaf-out alters the time between phenophases across temperate tree species
Aim
Authors
Xiaojun Geng, Yongshuo F. Fu, Shilong Piao, Fanghua Hao, Hans J. De Boeck, Xuan Zhang, Shouzhi Chen, Yahui Guo, Janet S. Prevéy, Yann Vitasse, Josep Penuelas, Ivan A. Janssens, Nils Christian Stenseth
A unified perspective of seismicity and fault coupling along the San Andreas Fault A unified perspective of seismicity and fault coupling along the San Andreas Fault
The San Andreas Fault (SAF) showcases the breadth of possible earthquake sizes and occurrence behavior; in particular, the central SAF is a microcosm of such diversity. This section also exhibits the spectrum of fault coupling from locked to creeping. Here, we show that the observations of aseismic slip, temporal clustering of seismicity, and spatial variations in earthquake size...
Authors
Y.-K. Liu, Z. Ross, Elizabeth S. Cochran, N. Lapusta
Coupling process-based and empirical models to assess management options to meet conservation goals Coupling process-based and empirical models to assess management options to meet conservation goals
Conservation lands face a mounting threat of ecosystem transformation and the loss of biodiversity from the invasion of fire-prone perennial and annual grasses. Managers must make difficult decisions to find efficient ways to expend limited resources to manage large and complex landscapes amidst substantial uncertainty regarding effective treatment strategies, climates, and invader...
Authors
Catherine S. Jarnevich, Catherine Cullinane Thomas, Nicholas E. Young, Perry Grissom, Dana M. Backer, Leonardo Frid
INHABIT: A web-based decision support tool for invasive plant species habitat visualization and assessment across the contiguous United States INHABIT: A web-based decision support tool for invasive plant species habitat visualization and assessment across the contiguous United States
Narrowing the communication and knowledge gap between producers and users of scientific data is a longstanding problem in ecological conservation and land management. Decision support tools (DSTs), including websites or interactive web applications, provide platforms that can help bridge this gap. DSTs can most effectively disseminate and translate research results when producers and...
Authors
Peder Engelstad, Catherine S. Jarnevich, Terri Hogan, Helen R. Sofaer, Ian S. Pearse, Jennifer Sieracki, Neil Frakes, Julia Sullivan, Nicholas E. Young, Janet S. Prevéy, Pairsa Nicole Belamaric, Jillian Marie Laroe
Fluoride in thermal and non-thermal groundwater: Insights from geochemical modeling Fluoride in thermal and non-thermal groundwater: Insights from geochemical modeling
High fluoride (F) groundwaters (>1 mg/L) have been recognized as a water quality problem for nearly a century and occur in many countries worldwide. The affected aquifers can be sedimentary, metamorphic or igneous rocks, but the process giving rise to high-F concentrations has been studied with geochemical modeling and an examination of the rock sources. The association of high-F with...
Authors
D. Kirk Nordstrom
Elevations of mangrove forests of Pohnpei, Micronesia Elevations of mangrove forests of Pohnpei, Micronesia
Mangrove surface elevation is the crux of mangrove vulnerability to sea level rise. Local topography influences critical periods of tidal inundation that govern distributions of mangrove species and dictates future distributions. This study surveyed ground surface elevations of the extensive mangroves of Pohnpei, Federated States of Micronesia, integrating four survey technologies to...
Authors
Joanna C Ellison, Kevin J. Buffington, Karen M. Thorne, Dean B. Gesch, Jeffrey Irwin, Jeffrey J. Danielson
New insights into the occurrence and implications of mobile water in gas hydrate systems New insights into the occurrence and implications of mobile water in gas hydrate systems
Gas hydrate production technologies commonly feature reservoir depressurization. Depressurization occurs when a pressure gradient is established in a well, drawing mobile water from the reservoir and reducing reservoir pressure. As such, the occurrence of mobile water is a necessary condition for effective gas production from gas hydrate reservoirs using common borehole-based methods...
Authors
Ray Boswell, Koji Yamamoto, Machiko Tamaki, Timothy S. Collett, George Moridis, Evgeniy Myshakin
Volcano geodesy using InSAR in 2020: The past and next decades Volcano geodesy using InSAR in 2020: The past and next decades
The study of volcano deformation has grown significantly through they year 2020 since the development of interferometric synthetic aperture radar (InSAR) in the 1990s. This relatively new data source, which provides evidence of changes in subsurface magma storage and pressure without the need for ground-based equipment, has matured during the past decade. It now provides a means to...
Authors
Michael Poland, Howard Zebker
Permeability measurement and prediction with nuclear magnetic resonance analysis of gas hydrate-bearing sediments recovered from Alaska North Slope 2018 Hydrate-01 Stratigraphic Test Well Permeability measurement and prediction with nuclear magnetic resonance analysis of gas hydrate-bearing sediments recovered from Alaska North Slope 2018 Hydrate-01 Stratigraphic Test Well
Permeability of porous media, such as oil and gas reservoirs, is the crucial material parameter for predicting their hydraulic behavior. A nuclear magnetic resonance (NMR) analyzer is widely used as a powerful tool to predict permeability of various media. NMR T2 (transverse or spin–spin) relaxation time distribution, which is related to pore size distribution, gives the information to...
Authors
Jun Yoneda, Kiyofumi Suzuki, Yusuke Jin, Satoshi Ohtsuki, Timothy S. Collett, Ray Boswell, Yuki Maehara, Norihiro Okinaka
Validating predicted site response in sedimentary basins from 3D ground motion simulations Validating predicted site response in sedimentary basins from 3D ground motion simulations
We introduce procedures to validate site response in sedimentary basins as predicted using ground motion simulations. These procedures aim to isolate contributions of site response to computed intensity measures relative to those from seismic source and path effects. In one of the validation procedures, simulated motions are analyzed in the same manner as earthquake recordings to derive...
Authors
Chukwuebuka C Nweke, Jonathan P. Stewart, Robert Graves, Christine A. Goulet, Scott J Brandenberg
Characterizing unrest: A retrospective look at 20 years of gas emissions and seismicity at Iliamna Volcano, Alaska Characterizing unrest: A retrospective look at 20 years of gas emissions and seismicity at Iliamna Volcano, Alaska
Episodes of unrest are not as well documented as eruptions at most volcanoes globally. Iliamna is an andesitic stratovolcano in the Cook Inlet of Alaska that has experienced several episodes of unrest. Unrest in 1996 was previously studied. Here we present data from a minor period of unrest between 2002 and 2006, and a more significant period in 2012. None of the episodes led to an...
Authors
Cynthia Werner, John Power, Peter J. Kelly, Stephanie G. Prejean, Christoph Kern
Exploring genetic variation and population structure in a threatened species, Noturus placidus, with whole-genome sequence data Exploring genetic variation and population structure in a threatened species, Noturus placidus, with whole-genome sequence data
The Neosho madtom (Noturus placidus) is a small catfish, generally less than 3 inches in length, unique to the Neosho-Spring River system within the Arkansas River Basin. It was federally listed as threatened in 1990, largely due to habitat loss. For conservation efforts, we generated whole-genome sequence data from 10 Neosho madtom individuals originating from 3 geographically separated
Authors
Lynsey K. Whitacre, Mark L. Wildhaber, Gary S. Johnson, Harly J. Durbin, Troy N. Rowan, Robert D. Schnabel, Tendai Mhlanga-Mutangadura, Vernon M. Tabor, Daniel Fenner, Jared E. Decker