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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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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
Kelp-forest dynamics controlled by substrate complexity Kelp-forest dynamics controlled by substrate complexity
The factors that determine why ecosystems exhibit abrupt shifts in state are of paramount importance for management, conservation, and restoration efforts. Kelp forests are emblematic of such abruptly shifting ecosystems, transitioning from kelp-dominated to urchin-dominated states around the world with increasing frequency, yet the underlying processes and mechanisms that control their...
Authors
Zachary Randell, Michael C. Kenner, Joseph A. Tomoleoni, Julie L. Yee, Mark Novak
Classifying behavior from short-interval biologging data: An example with GPS tracking of birds Classifying behavior from short-interval biologging data: An example with GPS tracking of birds
Recent advances in digital data collection have spurred accumulation of immense quantities of data that have potential to lead to remarkable ecological insight, but that also present analytic challenges. In the case of biologging data from birds, common analytical approaches to classifying movement behaviors are largely inappropriate for these massive data sets.We apply a framework for...
Authors
Silas Bergen, Manuela Huso, A. Duerr, Missy A Braham, Todd E. Katzner, Sara Schmuecker, Tricia A. Miller
Analyzing the effects of land cover change on the water balance for case study watersheds in different forested ecosystems in the USA Analyzing the effects of land cover change on the water balance for case study watersheds in different forested ecosystems in the USA
We analyzed impacts of interannual disturbance on the water balance of watersheds in different forested ecosystem case studies across the United States from 1985 to 2016 using a remotely sensed long-term land cover monitoring record (U.S. Geological Survey Land Change Monitoring, Assessment, and Projection (LCMAP) Collection 1.0 Science products), gridded precipitation and evaporation...
Authors
Nathan C. Healey, Jennifer Rover
Rainfall triggering of post-fire debris flows over a 28-year period near El Portal, California, USA Rainfall triggering of post-fire debris flows over a 28-year period near El Portal, California, USA
Wildfires frequently affect the steep hillslopes near El Portal, California (United States), a small community established during the California Gold Rush in the mid-1800s. In addition to the historical significance of El Portal, State Route 140 (SR 140) is a major transportation and economic corridor connecting the San Joaquin Valley to Yosemite National Park (YNP). In 2019, an...
Authors
Jerome V. De Graff, Dennis M. Staley, Greg M. Stock, Kellen Takenaka, Alan L. Gallegos, Chad K. Neptune
Rockfall kinematics from massive rock cliffs: Outlier boulders and flyrock from Whitney Portal, California, rockfalls Rockfall kinematics from massive rock cliffs: Outlier boulders and flyrock from Whitney Portal, California, rockfalls
Geologic conditions and topographic setting are among the most critical factors for assessing rockfall hazards. However, other subtle features of rockfall motion may also govern the runout of rockfall debris, particularly for those sourced from massive cliffs where debris can have substantial momentum during transport. Rocks may undergo collisions with trees and talus boulders, with the...
Authors
Brian D. Collins, Skye C. Corbett, Elizabeth Jean Horton, Alan J. Gallegos
Unravelling a 2300 year long sedimentary record of megathrust and intraslab earthquakes in proglacial Skilak Lake, south-central Alaska Unravelling a 2300 year long sedimentary record of megathrust and intraslab earthquakes in proglacial Skilak Lake, south-central Alaska
Seismic hazards in subduction settings typically arise from megathrust, intraslab and crustal earthquake sources. Despite the frequent occurrence of intraslab earthquakes in subduction zones and their potential threat to communities, their long-term recurrence behaviour is barely studied. Sedimentary sequences in lakes may register ground shaking from different seismic sources. This...
Authors
Nore Praet, Maarten Van Daele, Jasper Moernaut, Thomas Mestdagh, Thomas Vandorpe, Britta J.L. Jensen, Robert C. Witter, Peter J. Haeussler, Marc De Batist