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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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Foreword to the special Issue on ‘The rapidly expanding role of drones as a tool for wildlife research’ Foreword to the special Issue on ‘The rapidly expanding role of drones as a tool for wildlife research’

Drones have emerged as a popular wildlife research tool, but their use for many species and environments remains untested and research is needed on validation of sampling approaches that are optimised for unpiloted aircraft. Here, we present a foreword to a special issue that features studies pushing the taxonomic and innovation boundaries of drone research and thus helps address these...
Authors
Aaron J Wirsing, Aaron N. Johnston, Jeremy J. Kiszka

Prospective and retrospective evaluation of the U.S. Geological Survey public aftershock forecast for the 2019-2021 Southwest Puerto Rico Earthquake and aftershocks Prospective and retrospective evaluation of the U.S. Geological Survey public aftershock forecast for the 2019-2021 Southwest Puerto Rico Earthquake and aftershocks

The Mw 6.4 Southwest Puerto Rico Earthquake of 7 January 2020 was accompanied by a robust fore‐ and aftershock sequence. The U.S. Geological Survey (USGS) has issued regular aftershock forecasts for more than a year since the mainshock, available on a public webpage. Forecasts were accompanied by interpretive and informational material, published in English and Spanish. Informational...
Authors
Nicholas van der Elst, Jeanne L. Hardebeck, Andrew J. Michael, Sara K. McBride, Elizabeth Vanacore

Multi-species inference of exotic annual and native perennial grasses in rangelands of the western United States using Harmonized Landsat and Sentinel-2 data Multi-species inference of exotic annual and native perennial grasses in rangelands of the western United States using Harmonized Landsat and Sentinel-2 data

The invasion of exotic annual grass (EAG), e.g., cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae), into rangeland ecosystems of the western United States is a broad-scale problem that affects wildlife habitats, increases wildfire frequency, and adds to land management costs. However, identifying individual species of EAG abundance from remote sensing, particularly...
Authors
Devendra Dahal, Neal J. Pastick, Stephen P. Boyte, Sujan Parajuli, Michael J. Oimoen, Logan J. Megard

Ground failure triggered by the 7 January 2020 M6.4 Puerto Rico earthquake Ground failure triggered by the 7 January 2020 M6.4 Puerto Rico earthquake

The 7 January 2020 M 6.4 Puerto Rico earthquake, the mainshock of an extended earthquake sequence, triggered significant ground failure. In this study, we detail the ground failure that occurred based largely on a postearthquake field reconnaissance campaign that we conducted. We documented more than 300 landslides, mainly rock falls that were concentrated in areas where peak ground...
Authors
Kate E. Allstadt, Eric M. Thompson, Desiree Bayouth Garcia, Edwin Irizarry Brugman, K. Stephen Hughes, Robert G. Schmitt

Baseline gene expression levels in Falkland-Malvinas Island penguins: Towards a new monitoring paradigm Baseline gene expression levels in Falkland-Malvinas Island penguins: Towards a new monitoring paradigm

Health diagnostics of wildlife have historically relied on the evaluation of select serum biomarkers and the identification of a contaminant or pathogen burden within specific tissues as an indicator of a level of insult. However, these approaches fail to measure the physiological reaction of the individual to stressors, thus limiting the scope of interpretation. Gene-based health...
Authors
Lizabeth Bowen, Shannon C. Waters-Dynes, Jeffrey L Stott, Ann Duncan, Randi Meyerson, Sarah Woodhouse

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 Sundstrom

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
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