Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2537
Width and dip of the southern San Andreas Fault at Salt Creek from modeling of geophysical data Width and dip of the southern San Andreas Fault at Salt Creek from modeling of geophysical data
We investigate the geometry and width of the southernmost stretch of the San Andreas Fault zone using new gravity and magnetic data along line 7 of the Salton Seismic Imaging Project. In the Salt Creek area of Durmid Hill, the San Andreas Fault coincides with a complex magnetic signature, with high-amplitude, short-wavelength magnetic anomalies superposed on a broader magnetic anomaly...
Authors
Victoria E. Langenheim, Noah D. Athens, Daniel S. Scheirer, Gary S. Fuis, Michael J. Rymer, Mark R. Goldman
Uncertainty and risk evaluation during the exploration stage of geothermal development Uncertainty and risk evaluation during the exploration stage of geothermal development
Quantifying and representing uncertainty for geothermal systems is often ignored, in practice, during the exploration phase of a geothermal development project. We propose that this occurs potentially because the task seems so formidable. The primary goal of this paper is to initiate a dialogue within the geothermal community about: which geothermal uncertainties should receive the most...
Authors
Jeffrey B. Witter, Whitney J. Trainor-Guitton, Drew L. Siler
Geology and geophysics applied to groundwater hydrology at Fort Irwin, California Geology and geophysics applied to groundwater hydrology at Fort Irwin, California
Geologic and geophysical investigations in the vicinity of Fort Irwin National Training Center, California, have been completed in support of groundwater investigations, and are presented in eight chapters of this report. A generalized surficial geologic map along with field and borehole investigations conducted during 2010–11 provide a lithostratigraphic and structural framework for the...
Tectonic evolution of the Tualatin basin, northwest Oregon, as revealed by inversion of gravity data Tectonic evolution of the Tualatin basin, northwest Oregon, as revealed by inversion of gravity data
The Tualatin basin, west of Portland (Oregon, USA), coincides with a 110 mGal gravity low along the Puget-Willamette lowland. New gravity measurements (n = 3000) reveal a three-dimensional (3-D) subsurface geometry suggesting early development as a fault-bounded pull-apart basin. A strong northwest-trending gravity gradient coincides with the Gales Creek fault, which forms the...
Authors
Darcy McPhee, Victoria E. Langenheim, Ray E. Wells, Richard J. Blakely
Climate Change 2014: Technical Summary Climate Change 2014: Technical Summary
Human interference with the climate system is occurring (WGI AR5 SPM Section D.3; WGI AR5 Sections 2.2, 6.3, 10.3 to 10.6, 10.9). Climate change poses risks for human and natural systems. The assessment of impacts, adaptation, and vulnerability in the Working Group II contribution to the IPCC’s Fifth Assessment Report (WGII AR5) evaluates how patterns of risks and potential benefits are...
Authors
Chrisopher B. Field, Vicente Barros, Katherine Mach, Michael Mastrandrea, Maarten van Aalst, Niel Adger, Douglas J Arent, Jonathan Barnett, Richard Betts, Eren Bilir, Joern Birkmann, Joann Carmin, Dave Chadee, Andrew Challinor, Monalisa Chaterjee, Wolfgang Cramer, Debra Davidson, Yuka Estrada, Jean-Pierre Gatusso, Yasuakai Hijioka, Gary Yohe, Margaret Hiza, Ove Hoegh-Guldberg, He-Qing Huang, Gregory Insarov, Roger Jones, Sari Kovats, Patricia Romero Lankao, Joan Nymand Larsen, Inigo Losada, Jose Marengo, Roger McLean, Linda Mearns, Reinhard Mechler, John Morton, Isabelle Niang, Taikan Oki, Jane Mukarugwiza Olwoch, Maggie Opondo, Elvira Poloczanska, Hans #NAME? Portner, Andy Reisinger, Aromar Revi, Daniela Schmidt, Rebecca Shaw, William Solecki, Daithi Stone, John Stone, Ken Strzepek, Avelino G. Suarez, Petra Tschakert, Riccardo Valentini, Sebastian Vicuna, Alicia Villamizar, Katharine Vincent, Rachel Warren, Leslie White, Thomas Wilbanks, Poh Poh Wong
Thermochronology of Cretaceous batholithic rocks in the northern Peninsular Ranges batholith, southern California: Implications for the Late Cretaceous tectonic evolution of southern California Thermochronology of Cretaceous batholithic rocks in the northern Peninsular Ranges batholith, southern California: Implications for the Late Cretaceous tectonic evolution of southern California
The thermochronology for several suites of Mesozoic metamorphic and plutonic rocks collected throughout the northern Peninsular Ranges batholith (PRB) was studied as part of a collaborative isotopic study to further our understanding of the magmatic and tectonic history of southern California. These sample suites include: a traverse through the plutonic rocks across the northern PRB (N =...
Authors
Daniel P. Miggins, Wayne R. Premo, Lawrence W. Snee, Ross Yeoman, Nancy D. Naeaer, Charles W. Naeser, Douglas M. Morton
Preliminary isostatic residual gravity map of the Tremonton 30' x 60' quadrangle, Box Elder and Cache Counties, Utah, and Franklin and Oneida Counties, Idaho Preliminary isostatic residual gravity map of the Tremonton 30' x 60' quadrangle, Box Elder and Cache Counties, Utah, and Franklin and Oneida Counties, Idaho
A new isostatic residual gravity map of the Tremonton 30' x 60' quadrangle of Utah is based on compilation of preexisting data and new data collected by the Utah and U.S. Geological Surveys. Pronounced gravity lows occur over North Bay, northwest of Brigham City, and Malad and Blue Creek Valleys, indicating significant thickness of low-density Tertiary sedimentary rocks and deposits...
Authors
Victoria E. Langenheim, R.Q. Oaks, H. Willis, A.I. Hiscock, Bruce A. Chuchel, Jose J. Rosario, C.L. Hardwick
Segmentation of plate coupling, fate of subduction fluids, and modes of arc magmatism in Cascadia, inferred from magnetotelluric resistivity Segmentation of plate coupling, fate of subduction fluids, and modes of arc magmatism in Cascadia, inferred from magnetotelluric resistivity
Five magnetotelluric (MT) profiles have been acquired across the Cascadia subduction system and transformed using 2-D and 3-D nonlinear inversion to yield electrical resistivity cross sections to depths of ∼200 km. Distinct changes in plate coupling, subduction fluid evolution, and modes of arc magmatism along the length of Cascadia are clearly expressed in the resistivity structure...
Authors
Philip E. Wannamaker, Rob L. Evans, Paul A. Bedrosian, Martyn J. Unsworth, Virginie Maris, R. Shane McGary
Mapping saltwater intrusion in the Biscayne Aquifer, Miami-Dade County, Florida using transient electromagnetic sounding Mapping saltwater intrusion in the Biscayne Aquifer, Miami-Dade County, Florida using transient electromagnetic sounding
Saltwater intrusion in southern Florida poses a potential threat to the public drinking-water supply that is typically monitored using water samples and electromagnetic induction logs collected from a network of wells. Transient electromagnetic (TEM) soundings are a complementary addition to the monitoring program because of their ease of use, low cost, and ability to fill in data gaps...
Authors
David V. Fitterman
Petrology and chemistry of the Green Acres gabbro complex near Winchester, Riverside County, California Petrology and chemistry of the Green Acres gabbro complex near Winchester, Riverside County, California
The Cretaceous Green Acres layered igneous complex, northeast of Winchester, California, is composed of a suite of olivine- and hornblende-bearing gabbros in the Peninsular Ranges batholith within the Perris tectonic block. A consistent mineral assemblage is observed throughout the complex, but there is considerable textural and modal heterogeneity. Both preclude a consistent set of...
Authors
Byron R. Berger
The Wallula fault and tectonic framework of south-central Washington, as interpreted from magnetic and gravity anomalies The Wallula fault and tectonic framework of south-central Washington, as interpreted from magnetic and gravity anomalies
The Yakima fold and thrust belt (YFTB) in central Washington has accommodated regional, mostly north-directed, deformation of the Cascadia backarc since prior to emplacement of Miocene flood basalt of the Columbia River Basalt Group (CRBG). The YFTB consists of two structural domains. Northern folds of the YFTB strike eastward and terminate at the western margin of a 20-mGal negative...
Authors
Richard J. Blakely, Brian L. Sherrod, Craig S. Weaver, Ray E. Wells, Alan C. Rohay
Modeling the hydrogeophysical response of lake talik evolution Modeling the hydrogeophysical response of lake talik evolution
Geophysical methods provide valuable information about subsurface permafrost and its relation to dynamic hydrologic systems. Airborne electromagnetic data from interior Alaska are used to map the distribution of permafrost, geological features, surface water, and groundwater. To validate and gain further insight into these field datasets, we also explore the geophysical response to...
Authors
Burke J. Minsley, Tristan Wellman, Michelle Ann Walvoord, Andre Revil