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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.

Filter Total Items: 74207

Apparent non-double-couple components as artifacts of moment tensor inversion

Compilations of earthquake moment tensors from global and regional catalogs find pervasive non-double-couple (NDC) components with a mean deviation from a double-couple (DC) source of around 20%. Their distributions vary only slightly with magnitude, faulting mechanism, or geologic environments. This consistency suggests that for most earthquakes, especially smaller ones whose rupture processes ar
Authors
Boris Rösler, Seth Stein, Adam T. Ringler, Jiří Vackár

Preliminary implications of viscoelastic ray theory for anelastic seismic tomography models

The recent developments in general viscoelastic ray theory provide a rigorous mathematical framework for anelastic seismic tomography. They provide closed‐form solutions of forward ray‐tracing and simple inverse problems for anelastic horizontal and spherical layered media with material gradients. They provide ray‐tracing computation algorithms valid for all angles of incidence that account for ch
Authors
Roger D. Borcherdt

Deep learning workflow to support in-flight processing of digital aerial imagery for wildlife population surveys

Deep learning shows promise for automating detection and classification of wildlife from digital aerial imagery to support cost-efficient remote sensing solutions for wildlife population monitoring. To support in-flight orthorectification and machine learning processing to detect and classify wildlife from imagery in near real-time, we evaluated deep learning methods that address hardware limitati
Authors
Tsung-Wei Ke, Stella X Yu, Mark D. Koneff, David L. Fronczak, Luke J. Fara, Travis Harrison, Kyle Lawrence Landolt, Enrika Hlavacek, Brian R. Lubinski, Timothy White

Propensity score matching mitigates risk of faulty inferences in observational studies of effectiveness of restoration trials

Determining effectiveness of restoration treatments is an important requirement of adaptive management, but it can be non-trivial where only portions of large and heterogeneous landscapes of concern can be treated and sampled. Bias and non-randomness in the spatial deployment of treatment and thus sampling is nearly unavoidable in the data available for large-scale management trials, and the bioph
Authors
Chad Raymond Kluender, Matthew Germino, Christopher A Anthony

Identifying an understudied interface: Preliminary evaluation of the use of retention ponds on commercial poultry farms by wild waterfowl

While the recent incursion of highly pathogenic avian influenza into North America has resulted in notable losses to the commercial poultry industry, the mechanism by which virus enters commercial poultry houses is still not understood. One theorized mechanism is that waterfowl shed virus into the environment surrounding poultry farms, such as into retention ponds, and is then transmitted into pou
Authors
Jeffery D. Sullivan, Ayla McDonough, Lauren Lescure, Diann Prosser

Quantifying and evaluating strategies to decrease carbon dioxide emissions generated from tourism to Yellowstone National Park

The tourism industry needs strategies to reduce emissions and hasten the achievement of global carbon dioxide (CO2) emission reduction targets. Using a case study approach, we estimated CO2 emissions related to park tourism in Yellowstone National Park (USA) generated from transit to and from the park, transit within the park, accommodations, and park operations. Results indicate tourism to Yellow
Authors
Emily J. Wilkins, Dani T. Dagan, Jordan W. Smith

Effects and perceptions of weather, climate, and climate change on outdoor recreation and nature-based tourism in the United States: A systematic review

Weather, climate, and climate change all effect outdoor recreation and tourism, and will continue to cause a multitude of effects as the climate warms. We conduct a systematic literature review to better understand how weather, climate, and climate change affect outdoor recreation and nature-based tourism across the United States. We specifically explore how the effects differ by recreational acti
Authors
Emily J. Wilkins, Lydia Horne

Range-wide genetic analysis of an endangered bumble bee (Bombus affinis, Hymenoptera: Apidae) reveals population structure, isolation by distance, and low colony abundance

Declines in bumble bee species range and abundances are documented across multiple continents and have prompted the need for research to aid species recovery and conservation. The rusty patched bumble bee (Bombus affinis) is the first federally listed bumble bee species in North America. We conducted a range-wide population genetics study of B. affinis from across all extant conservation units to
Authors
John Mola, Ian Pearse, Michelle Boone, Elaine Evans, Mark Hepner, Robert Jean, Jade Kochanski, Cade Nordmeyer, Eric Runquist, Tamara A. Smith, Jaime Strange, Jay Watson, Jonathan B Koch

Measuring and interpreting the surface and shallow subsurface process influences on coastal wetland elevation: A review

A century ago, measuring elevation in tidal wetlands proved difficult, as survey leveling of soft marsh soils relative to a fixed datum was error prone. For 60 years, vertical accretion measures from marker horizons were used as analogs of elevation change. But without a direct measure of elevation, it was not possible to measure the total influence of surface and subsurface processes on elevation
Authors
Donald Cahoon

Vegetation, fuels, and fire-behavior responses to linear fuel-break treatments in and around burned sagebrush steppe: Are we breaking the grass-fire cycle?

BackgroundLinear fuel breaks are being implemented to moderate fire behavior and improve wildfire containment in semiarid landscapes such as the sagebrush steppe of North America, where extensive losses in perennial vegetation and ecosystem functioning are resulting from invasion by exotic annual grasses (EAGs) that foster large and recurrent wildfires. However, fuel-break construction can also po
Authors
Matthew Germino, Samuel J. Price, Susan J Prichard

Comparing modern identification methods for wild bees: Metabarcoding and image-based morphological taxonomic assignment

With the decline of bee populations worldwide, studies determining current wild bee distributions and diversity are increasingly important. Wild bee identification is often completed by experienced taxonomists or by genetic analysis. The current study was designed to compare two methods of identification including: (1) morphological identification by experienced taxonomists using images of field-c
Authors
Cassandra Smith, Robert S. Cornman, Jennifer A. Fike, Johanna M. Kraus, Sara J. Oyler-McCance, Carrie E Givens, Michelle Hladik, Mark W. Vandever, Dana W. Kolpin, Kelly Smalling

Nontarget effects of pre-emergent herbicides and a bioherbicide on soil resources, processes, and communities

Community-type conversions, such as replacement of perennials by exotic annual grasses in semiarid desert communities, are occurring due to plant invasions that often create positive plant–soil feedbacks, which favor invaders and make restoration of native perennials difficult. Exotic annual grass control measures, such as pre-emergent herbicides, can also alter soil ecosystems directly or indirec
Authors
Brynne E. Lazarus, Matthew Germino, Marie-Anne de Graaff