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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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ETAS-positive: Extracting unbiased epidemic-type aftershock models from incomplete earthquake catalogs ETAS-positive: Extracting unbiased epidemic-type aftershock models from incomplete earthquake catalogs

Earthquake catalogs are inherently incomplete, and short-term fluctuations in catalog completeness can strongly bias estimates of seismicity parameters. Here, we extend the positive statistics framework recently introduced for estimating Gutenberg–Richter a and b values to the Epidemic-Type Aftershock Sequence (ETAS) model. The approach focuses on complete magnitude–time intervals...
Authors
Nicholas J. van der Elst, Sebastian Hainzl

Incorporating wetland drowning thresholds to assess the spatiotemporal variability in potential wetland migration and submergence from sea-level rise Incorporating wetland drowning thresholds to assess the spatiotemporal variability in potential wetland migration and submergence from sea-level rise

In the coming decades sea-level rise rates could exceed the upper bounds of coastal wetland vertical movement leading to wetland submergence. Consequently, understanding the spatiotemporal variability of wetland migration and submergence at regional and national scales can inform decision making. In this study, we developed an approach that addresses elevation error in digital elevation...
Authors
Nicholas M. Enwright, Michael J. Osland, Jena A. Moon, Bethanie M. Simons, Joseph D. Lancaster, Sarah E. Lehnen, Colt R. Sanspree, Camille L. Stagg, Barry C. Wilson

Deep learning models for mapping surficial geology in selected physiographic regions of New York Deep learning models for mapping surficial geology in selected physiographic regions of New York

Surficial geologic mapping is required for decisions including infrastructure and water-resource development and management. Deep learning, a type of machine learning that uses training data to self-learn and perform tasks, is explored as a tool to help increase efficiency of the labour- and time-intensive mapping process. Deep learning models were trained, and their potential to aid in...
Authors
Joshua C. Woda, Jason S. Finkelstein, William E. Odom, John H. Williams

Animal immortality lives in our data Animal immortality lives in our data

No abstract available.
Authors
David Edward Ausband

The rising threat of lead: Trends in fatalities of California condors The rising threat of lead: Trends in fatalities of California condors

Endangered species face threats that change over time, and understanding variation in the importance of threats is valuable for guiding species recovery. The reintroduced population of critically endangered California condors has faced a number of threats over the three decades since the species was first released back to the wild. We modeled interannual and interseasonal trends in the...
Authors
Molly Astell, Steve Kirkland, Punzalan. Arrianna, Todd E. Katzner

Depositional environment and diagenetic history of gas hydrate-bearing sediments of the Alaska North Slope (HYDRATE 02 Geo Data Well) Depositional environment and diagenetic history of gas hydrate-bearing sediments of the Alaska North Slope (HYDRATE 02 Geo Data Well)

We characterized the lithological, solid-phase geochemical, and rock magnetic properties of sediment cores from subpermafrost strata on the Alaska North Slope collected as part of the U.S. Department of Energy (DOE), the Japan Organization for Metals and Energy Security (JOGMEC), and the U.S. Geological Survey (USGS) Collaborative Gas Hydrate Research and Development (R&D) Project in...
Authors
Stephen C. Phillips, Sarah Johnson Widlansky, Jun Yoneda, Akihiro Hiruta, Broden A.L. Grimm, Joel E. Johnson, Amy Geist, Melanie E. Holland, Peter J. Schultheiss, Timothy S. Collett

Restoring elk in Minnesota: Landowner support for restoring an elk population Restoring elk in Minnesota: Landowner support for restoring an elk population

Public support is critical to successfully restore wildlife populations and avoid future human–wildlife conflict. We used a structural equation model (SEM) to analyze 2550 survey responses from landowners in northeast Minnesota to examine the influence of four psychological constructs on support for restoring a wild, free-ranging elk (Cervus canadensis) population in the region. Our...
Authors
Eric M. Walberg, David C. Fulton, Michael W. Schrage, James D. Forester, Adam C. Landon, Craig A. Miller

Emergent headwater types for watershed monitoring, research, and planning Emergent headwater types for watershed monitoring, research, and planning

Headwaters—that is headwater streams and the watersheds they drain—strongly influence water quality, ecosystem services, and hydrologic connectivity, yet remain poorly mapped, monitored, and understood at large spatial scales. Using available spatial data to classify headwater “types” could therefore enhance the utility of sparse monitoring data to advance research and watershed planning...
Authors
Erin C. Seybold, John C. Hammond, Admin Husic, Hilary McMillan, Heather Golden, Jay R. Christensen, Catalina Segura, Margaret Zimmer, Adam N. Price, Kristin Jaeger, Li Li, D. Tyler Mahoney, Fred Cheng, C. Nathan Jones, Christa Kelleher, Roy Sando, Chuck Lane, Adam Ward

Permeability and compressibility of “seal” sediment overlying the B1 sand gas hydrate reservoir: Hydrate 02 Geo Data Well, Prudhoe Bay unit, Alaska North Slope Permeability and compressibility of “seal” sediment overlying the B1 sand gas hydrate reservoir: Hydrate 02 Geo Data Well, Prudhoe Bay unit, Alaska North Slope

An important element in evaluating the viability of extracting methane from a gas hydrate-bearing reservoir is establishing the effectiveness of the overlying bounding sediment as a seal to prevent gas loss, to enable effective depressurization, and to prevent fluid from entering the reservoir during production. This laboratory study presents results for index properties (e.g., grain...
Authors
Adrian V. Garcia, William F. Waite, Stephen C. Phillips, Jun Yoneda, Akihiro Hiruta, Timothy S. Collett

Core microbiomes as a potential fingerprinting method of Western USA dust sources Core microbiomes as a potential fingerprinting method of Western USA dust sources

Introduction: Changing frequency and intensity of dust emissions impacts ecosystems and human health. Dust carries microbes, nutrients, heavy metals, and other materials that may change environmental biogeochemistry at deposition sites. Identifying dust sources provides key information on where and when mitigation strategies should be employed. However, commonly used geochemical or...
Authors
DeTiare L. Leifi, Sarah C. Peterson, Jakob L. Young, Gregory T. Carling, Janice Brahney, Michael C. Duniway, Beth A. Newingham, Nicholas P. Webb, Travis W. Nauman, Zachary T. Aanderud
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