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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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Juvenile continental crust evolution in a modern oceanic arc setting: Petrogenesis of Cenozoic felsic plutons in Fiji, SW Pacific Juvenile continental crust evolution in a modern oceanic arc setting: Petrogenesis of Cenozoic felsic plutons in Fiji, SW Pacific

Viti Levu, Fiji, provides one of the best exposed Phanerozoic analogues for the formation of juvenile continental crust in an intra-oceanic setting. Tonalites and trondhjemites are present in several large (75–150 km2) adjacent, mid-Cenozoic plutons. We report major and trace element data including rare earth element (REE) and high-precision high field strength element (HFSE)...
Authors
Chris S. Marien, Elizabeth Kathleen Drewes-Todd, Allen Stork, Erin Todd, James B Gill, J. Elis Hoffman, Kenichiro Tani, Charlotte M. Allen, Carsten Munker

Combining tangential flow filtration and size fractionation of mesocosm water as a method for the investigation of waterborne coral diseases Combining tangential flow filtration and size fractionation of mesocosm water as a method for the investigation of waterborne coral diseases

The causative agents of most coral diseases today remain unknown, complicating disease response and restoration efforts. Pathogen identifications can be hampered by complex microbial communities naturally associated with corals and seawater, which create complicating “background noise” that can potentially obscure a pathogen’s signal. Here, we outline an approach to investigate...
Authors
James S. Evans, Valerie J. Paul, Blake Ushijima, Christina A. Kellogg

Mature diffuse tectonic block boundary revealed by the 2020 southwestern Puerto Rico seismic sequence Mature diffuse tectonic block boundary revealed by the 2020 southwestern Puerto Rico seismic sequence

Distributed faulting typically tends to coalesce into one or a few faults with repeated deformation. The progression of clustered medium-sized (≥Mw4.5) earthquakes during the 2020 seismic sequence in southwestern Puerto Rico (SWPR), modeling shoreline subsidence from InSAR, and sub-seafloor mapping by high-resolution seismic reflection profiles, suggest that the 2020 SWPR seismic...
Authors
Uri S. ten Brink, L Vanacore, E. J. Fielding, Jason Chaytor, A.M. Lopez-Venegas, Wayne E. Baldwin, David S. Foster, Brian D. Andrews

Shoaling wave shape estimates from field observations and derived bedload sediment rates Shoaling wave shape estimates from field observations and derived bedload sediment rates

The shoaling transformation from generally linear deep-water waves to asymmetric shallow-water waves modifies wave shapes and causes near-bed orbital velocities to become asymmetrical, contributing to net sediment transport. In this work, we used two methods to estimate the asymmetric wave shape from data at three sites. The first method converted wave measurements made at the surface to...
Authors
Tarandeep S. Kalra, Steven E. Suttles, Christopher R. Sherwood, John C. Warner, Alfredo Aretxabaleta, Gibson Robert Scott Leavitt

Empirical map-based nonergodic models of site response in the greater Los Angeles area Empirical map-based nonergodic models of site response in the greater Los Angeles area

We develop empirical estimates of site response at seismic stations in the Los Angeles area using recorded ground motions from 414 M 3–7.3 earthquakes in southern California. The data are from a combination of the Next Generation Attenuation‐West2 project, the 2019 Ridgecrest earthquakes, and about 10,000 newly processed records. We estimate site response using an iterative mixed‐effects...
Authors
Grace Alexandra Parker, Annemarie S. Baltay

Earthquake-derived seismic velocity changes during the 2018 caldera collapse of Kīlauea volcano Earthquake-derived seismic velocity changes during the 2018 caldera collapse of Kīlauea volcano

The 2018 Kīlauea caldera collapse produced extraordinary sequences of seismicity and deformation, with 62 episodic collapse events which significantly altered the landscape of the summit region. Despite decades of focused scientific studies at Kīlauea, detailed information about the internal structure of the volcano is limited. Recently developed techniques in seismic interferometry can...
Authors
Alicia J. Hotovec-Ellis, Brian Shiro, David R. Shelly, Kyle R. Anderson, Matt Haney, Weston Thelen, Emily K. Montgomery-Brown, Ingrid A. Johanson

Perfluoroalkyl and polyfluoroalkyl substances in groundwater used as a source of drinking water in the eastern United States Perfluoroalkyl and polyfluoroalkyl substances in groundwater used as a source of drinking water in the eastern United States

In 2019, 254 samples were collected from five aquifer systems to evaluate per- and polyfluoroalkyl substance (PFAS) occurrence in groundwater used as a source of drinking water in the eastern United States. The samples were analyzed for 24 PFAS, major ions, nutrients, trace elements, dissolved organic carbon (DOC), volatile organic compounds (VOCs), pharmaceuticals, and tritium. Fourteen...
Authors
Peter B. McMahon, Andrea K. Tokranov, Laura M. Bexfield, Bruce D. Lindsey, Tyler D. Johnson, Melissa A. Lombard, Elise Watson

Nutrient improvements in Chesapeake Bay: Direct effect of load reductions and implications for coastal management Nutrient improvements in Chesapeake Bay: Direct effect of load reductions and implications for coastal management

In Chesapeake Bay in the United States, decades of management efforts have resulted in modest reductions of nutrient loads from the watershed, but corresponding improvements in estuarine water quality have not clearly materialized. Generalized additive models were used to directly link river flows and nutrient loads from the watershed to nutrient trends in the estuary on a station-by...
Authors
Rebecca R. Murphy, Jennifer L. D. Keisman, Jon Harcum, Renee Karrh, Michael F. Lane, Elgin S. Perry, Qian Zhang

How much marsh restoration is enough to deliver wave attenuation coastal protection benefits? How much marsh restoration is enough to deliver wave attenuation coastal protection benefits?

As coastal communities grow more vulnerable to sea-level rise and increased storminess, communities have turned to nature-based solutions to bolster coastal resilience and protection. Marshes have significant wave attenuation properties and can play an important role in coastal protection for many communities. Many restoration projects seek to maximize this ecosystem service but how much...
Authors
Katherine A. Castagno, Neil K. Ganju, Michael W. Beck, Alison Bowden, Steven B. Scyphers

Behavioral state-dependent habitat selection and implications for animal translocations Behavioral state-dependent habitat selection and implications for animal translocations

Post-release monitoring of translocated animals is often used to inform future translocation protocols. Quantifying habitat selection of translocated individuals may help identify features that characterize good settlement habitat and thus inform the choice of future release sites. However, translocated animals often undergo post-release behavioural modification, and their habitat...
Authors
Simona Picardi, Peter S. Coates, Jesse L. Kolar, Shawn T. O’Neil, Steven R. Mathews, David K. Dahlgren

The Hawai'i groundwater recharge tool The Hawai'i groundwater recharge tool

This article discusses the design and implementation of the Hawai’i Groundwater Recharge Tool, an application for providing data and analyses of the impacts of land-cover modifications and changes in precipitation on groundwater-recharge rates for the island of O’ahu. This application uses simulation data based on a set of 29 land-cover types and 2 precipitation conditions to provide...
Authors
Jared H. McLean, Sean B. Cleveland, Kolja Rotzoll, Scot K. Izuka, Jason Leigh, Gwen A. Jacobs, Ryan Theriot

Invasion of Siberian elm (Ulmus pumila) along the South Platte River: The roles of seed source, human influence, and river geomorphology Invasion of Siberian elm (Ulmus pumila) along the South Platte River: The roles of seed source, human influence, and river geomorphology

Riparian ecosystems in the western USA have been invaded by non-native woody species deliberately introduced for stream bank stabilization, agricultural windbreaks, and urban shade. Recent work suggests that the non-native tree Ulmus pumila (Siberian elm) is capable of significant spread in western riparian ecosystems, that range infilling is still incomplete, and that the invasion is...
Authors
Lindsay Reynolds, Laura Perry, Patrick B. Shafroth, Gabrielle L. Katz, Andrew S. Norton
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