Publications
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Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary
Geophysical and geochemical data indicate there is abundant fluid expulsion in the Nootka fault zone (NFZ) between the Juan de Fuca and Explorer plates and the Nootka continental slope. Here we combine observations from > 20 years of investigations to demonstrate the nature of fluid-flow along the NFZ, which is the seismically most active region off Vancouver Island. Seismicity reaching...
Authors
M. Riedel, K .M. M. Rohr, G. D. Spence, D. Kelley, J. Delaney, L. Lapham, John Pohlman, R.D. Hyndman, E.C. Willoughby
Seismicity induced by massive wastewater injection near Puerto Gaitán, Colombia Seismicity induced by massive wastewater injection near Puerto Gaitán, Colombia
Seven years after the beginning of a massive wastewater injection project in eastern Colombia, local earthquake activity increased significantly. The field operator and the Colombian Geological Survey immediately reinforced the monitoring of the area. Our analysis of the temporal evolution of the seismic and injection data together with our knowledge of the geological parameters of the...
Authors
I Molina, J.S. Velasquez, Justin Rubinstein, A Garcia-Aristizabal, V Dionicio
Adjusted geomagnetic data—Theoretical basis and validation Adjusted geomagnetic data—Theoretical basis and validation
Adjusted geomagnetic data are magnetometer measurements with provisional correction factors applied such that vector quantities are oriented in a local Cartesian frame in which the X axis points north, the Y axis points east, and the Z axis points down. These correction factors are determined from so-called absolute measurements, which are “ground truth” observations made in the field...
Authors
E. Joshua Rigler, Abram E. Claycomb
Laboratory electrical conductivity of marine gas hydrate Laboratory electrical conductivity of marine gas hydrate
Methane hydrate was synthesized from pure water ice and flash frozen seawater, with varying amounts of sand or silt added. Electrical conductivity was determined by impedance spectroscopy, using equivalent circuit modeling to separate the effects of electrodes and to gain insight into conduction mechanisms. Silt and sand increase the conductivity of pure hydrate, we infer by contaminant...
Authors
Steven Constable, Ryan Lu, Laura A. Stern, Wyatt L. Du Frane, Jeffery J. Roberts
A global shape model for Saturn's moon Enceladus from a dense photogrammetric control network A global shape model for Saturn's moon Enceladus from a dense photogrammetric control network
A planetary bodys global shape provides both insight into its geologic evolution, and a key element of any Planetary Spatial Data Infrastructure (PSDI). NASAs Cassini mission to Saturn acquired more than 600 moderate- to high-resolution images ( 500 m/pixel) of the small, geologically active moon Enceladus. The moons internal global ocean and intriguing geology mark it as a candidate for...
Authors
Michael T. Bland, Lynn A. Weller, David Mayer, Brent A. Archinal
Localized fluid discharge by tensile cracking during the post-seismic period in subduction zones Localized fluid discharge by tensile cracking during the post-seismic period in subduction zones
It is thought that extensional structures (extensional cracks and normal faults) generated during the post-seismic period create fluid pathways that enhance the drainage of the subducting plate interface, thus reducing the pore pressure and increasing fault strength. However, it remains to be elucidated how much pore fluid pressure decreases by the extension crack formation. Here we...
Authors
Makoto Otsubo, Jeanne L. Hardebeck, Ayumu Miyakawa, Asuka Yamaguchi, Gaku Kimura
Coordination of planetary coordinate system recommendations by the IAU Working Group on Cartographic Coordinates and Rotational Elements–2020 status and future Coordination of planetary coordinate system recommendations by the IAU Working Group on Cartographic Coordinates and Rotational Elements–2020 status and future
Our goal is to request input from the lunar and planetary community regarding issues of planetary coordinate systems and cartography standards. We begin with an overview of the work of the International Astronomical Union Working Group on Cartographic Coordinates and Rotational Elements. We briefly describe the operations and membership of the Working Group, some of the various uses of...
Authors
Brent A. Archinal, C. H. Acton, A. Conrad, T. Duxbury, D. Hestroffer, J. L. Hilton, L. Jorda, Randolph L. Kirk, S. A. Klioner, J.-L. Margot, J. Oberst, F. Paganelli, J. Ping, K. Seidelmann, D. J. Tholen, I. P. Williams
Procedures for developing multi-period response spectra at non-conterminous United States sites Procedures for developing multi-period response spectra at non-conterminous United States sites
This study complements proposals to the Provisions Update Committee of the Building Seismic Safety Council that would incorporate multi-period response spectra (MPRS) in the 2020 edition of the NEHRP Recommended Seismic Provisions for New Buildings and Other Structures (2020 NEHRP Provisions) and related proposals to the ASCE 7-22 Seismic Subcommittee of the American Society of Civil...
Authors
Mai Tong, Robert D. Hanson, Charles A Kircher, Sanaz Rezaeian, Nico Luco
Calibration of the U.S. Geological Survey National Crustal Model Calibration of the U.S. Geological Survey National Crustal Model
The U.S. Geological Survey National Crustal Model (NCM) is being developed to include spatially varying estimates of site response in seismic hazard assessments. Primary outputs of the NCM are continuous velocity and density profiles from the Earth’s surface to the mantle transition zone at 410-kilometer (km) depth for each location on a 1-km grid across the conterminous United States...
Authors
Oliver S. Boyd
Documentation of Surface Fault Rupture and Ground‐Deformation Features Produced by the 4 and 5 July 2019 Mw 6.4 and Mw 7.1 Ridgecrest Earthquake Sequence Documentation of Surface Fault Rupture and Ground‐Deformation Features Produced by the 4 and 5 July 2019 Mw 6.4 and Mw 7.1 Ridgecrest Earthquake Sequence
The MwMw 6.4 and MwMw 7.1 Ridgecrest earthquake sequence occurred on 4 and 5 July 2019 within the eastern California shear zone of southern California. Both events produced extensive surface faulting and ground deformation within Indian Wells Valley and Searles Valley. In the weeks following the earthquakes, more than six dozen scientists from government, academia, and the private sector...
Authors
Daniel J. Ponti, James Luke Blair, Rosa Carla M, Kate Thomas, Alexandra Pickering, Sinan Akciz, Stephen J. Angster, Jean-Philipe Avouac, Jeffrey Bachhuber, Steven Bacon, Nicolas C. Barth, S. Bennett, Kelly Blake, Stephan Bork, Benjamin A. Brooks, Thomas Bullard, Paul A. Burgess, Colin Chupik, Timothy E. Dawson, Michael DeFrisco, Jaime E. Delano, Stephen B. DeLong, James D. Dolan, Andrea Donnellan, Christopher DuRoss, Todd Ericksen, Erik Frost, Gareth J. Funning, Ryan D. Gold, Nicholas A Graehl, Carlos Gutierrez, Elizabeth Haddon, Alexandra Elise Hatem, John Helms, Janis Hernandez, Christopher S. Hitchcock, Peter Holland, Kenneth W. Hudnut, Katherine J. Kendrick, Richard D Koehler, Ozgur Kozaci, Tyler C. Ladinsky, Robert Leeper, Christopher Madugo, Maxime Mareschal, James McDonald, Devin McPhillips, Christopher Milliner, Daniel Mongovin, Alexander Morelan, Stephanie Nale, Johanna Nevitt, Matt O’Neal, Brian J. Olsen, Michael Oskin, Salena Padilla, Jason Patton, Belle E. Philibosian, Ian Pierce, Cynthia Pridmore, Nathaniel Roth, David Sandwell, Katherine M. Scharer, Gordon G. Seitz, Drake Singleton, Bridget Smith-Konter, Eleanor Spangler, Brian J. Swanson, Jessica Thompson Jobe, Jerome Treiman, Francesca Valencia, Joshua Vanderwal, Alana Williams, Xiaohua Xu, Judith Zachariasen, Jade Zimmerman, Robert Zinke
Recording the aurora borealis (northern lights) at seismometers across Alaska Recording the aurora borealis (northern lights) at seismometers across Alaska
We examine three continuously recording data sets related to the aurora: all‐sky camera images, three‐component magnetometer data, and vertical‐component, broadband seismic data as part of the EarthScope project (2014 to present). Across Alaska there are six all‐sky cameras, 13 magnetometers, and >200>200 seismometers. The all‐sky images and magnetometers have the same objective, which...
Authors
C. Tape, Adam T. Ringler, D.L. Hampton
Citizen science collaboration with the U.S. Geological Survey in Alaska Citizen science collaboration with the U.S. Geological Survey in Alaska
Citizen science is science undertaken by the public, usually in collaboration with professional scientific institutions. It encourages citizens to tackle real-world scientific problems and augments traditional science by expanding the coverage of data collection and by reducing costs of fieldwork in remote locations. Information collected by volunteers enables us all to gain a deeper...
Authors
Elizabeth Powers, Dee Williams