Publications
Filter Total Items: 7611
Vapor transfer prior to the October 2004 eruption of Mount St. Helens, Washington Vapor transfer prior to the October 2004 eruption of Mount St. Helens, Washington
Dome lavas from the 2004 eruption of Mount St. Helens show elevated Li contents in plagioclase phenocrysts at the onset of dome growth in October 2004. These cannot be explained by variations in plagioclase-melt partitioning, but require elevated Li contents in coexisting melt, a fact confirmed by measurements of Li contents as high as 207 µg/g in coexisting melt inclusions. Similar Li...
Authors
A.J.R. Kent, J. Blundy, K. V. Cashman, K.M. Copper, C. Donnelly, John S. Pallister, M. Reagan, M.C. Rowe, Carl Thornber
Colored dissolved organic matter in Tampa Bay, Florida Colored dissolved organic matter in Tampa Bay, Florida
Absorption and fluorescence of colored dissolved organic matter (CDOM) and concentrations of dissolved organic carbon (DOC), chlorophyll and total suspended solids in Tampa Bay and its adjacent rivers were examined in June and October of 2004. Except in Old Tampa Bay (OTB), the spatial distribution of CDOM showed a conservative relationship with salinity in June, 2004 (aCDOM(400) = − 0...
Authors
Z. Chen, C. Hu, R.N. Conmy, F. Muller-Karger, P. Swarzenski
Late Quaternary distal tephra-fall deposits in lacustrine sediments, Kenai Peninsula, Alaska Late Quaternary distal tephra-fall deposits in lacustrine sediments, Kenai Peninsula, Alaska
Tephra-fall deposits from Cook Inlet volcanoes were detected in sediment cores from Tustumena and Paradox Lakes, Kenai Peninsula, Alaska, using magnetic susceptibility and petrography. The ages of tephra layers were estimated using 21 14C ages on macrofossils. Tephras layers are typically fine, gray ash, 1–5 mm thick, and composed of varying proportions of glass shards, pumice, and glass...
Authors
C.S. de Fontaine, D. S. Kaufman, Anderson R. Scott, A. Werner, Christopher F. Waythomas, T.A. Brown
Two lithospheric profiles across southern California derived from gravity and seismic data Two lithospheric profiles across southern California derived from gravity and seismic data
We present two detailed 2-D density transects for the crust and uppermost mantle across southern California using a linear gravity inversion technique. This technique parameterizes the crust and upper mantle as a set of blocks that are based on published geologic and seismic models. Each block can have a range of densities that are constrained where possible by borehole measurements...
Authors
T. Romanyuk, Walter D. Mooney, Shane T. Detweiler
Impacts of the 2004 Indian ocean tsunami on the southwest coasts of Sri Lanka Impacts of the 2004 Indian ocean tsunami on the southwest coasts of Sri Lanka
The 2004 Indian Ocean tsunami caused major landscape changes along the southwest coasts of Sri Lanka that were controlled by the flow, natural topography and bathymetry, and anthropogenic modifications of the terrain. Landscape changes included substantial beach erosion and scouring of return-flow channels near the beach, and deposition of sand sheets across the narrow coastal plain. In...
Authors
Robert A. Morton, John A. Goff, Scott L. Nichol
Deglacial climate variability in central Florida, USA Deglacial climate variability in central Florida, USA
Pollen and ostracode evidence from lacustrine sediments underlying modern Tampa Bay, Florida, document frequent and abrupt climatic and hydrological events superimposed on deglacial warming in the subtropics. Radiocarbon chronology on well-preserved mollusk shells and pollen residue from core MD02-2579 documents continuous sedimentation in a variety of non-marine habitats in a karst...
Authors
Debra A. Willard, C.E. Bernhardt, G. R. Brooks, T. M. Cronin, T. Edgar, R. Larson
Pre-eruption recharge of the Bishop magma system Pre-eruption recharge of the Bishop magma system
The 650 km3 rhyolitic Bishop Tuff (eastern California, USA), which is stratigraphically zoned with respect to temperatures of mineral equilibration, reflects a corresponding thermal gradient in the source magma chamber. Consistent with previous work, application of the new TitaniQ (Ti-in-quartz) thermometer to quartz phenocryst rims documents an ∼100 °C temperature increase with chamber...
Authors
D.A. Wark, W. Hildreth, F.S. Spear, D.J. Cherniak, E.B. Watson
Risk-targeted versus current seismic design maps for the conterminous United States Risk-targeted versus current seismic design maps for the conterminous United States
The probabilistic portions of the seismic design maps in the NEHRP Provisions (FEMA, 2003/2000/1997), and in the International Building Code (ICC, 2006/2003/2000) and ASCE Standard 7-05 (ASCE, 2005a), provide ground motion values from the USGS that have a 2% probability of being exceeded in 50 years. Under the assumption that the capacity against collapse of structures designed for these...
Authors
Nicolas Luco, Bruce R. Ellingwood, Ronald O. Hamburger, John D. Hooper, Jeffrey K. Kimball, Charles A. Kircher
Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline
Between 18 March and 27 October 2002, 220 air samples were collected on 209 of 224 calendar days, on top of a coastal atmospheric research tower in Erdemli, Turkey. The volume of air filtered for each sample was 340 liters. Two hundred fifty-seven bacterial and 2598 fungal colony forming units (CFU) were enumerated from the samples using a low-nutrient agar. Ground-based dust...
Authors
Dale W. Griffin, Nilgun Kubilay, Mustafa Kocak, Mike A. Gray, Timothy C. Borden, Eugene A. Shinn
USGS advances in integrated, high-resolution sea-floor mapping: inner continental shelf to estuaries USGS advances in integrated, high-resolution sea-floor mapping: inner continental shelf to estuaries
The U.S. Geological Survey (USGS) has been involved in geological mapping of the sea floor for the past thirty years. Early geophysical and acoustic mapping efforts using GLORIA (Geologic LOng Range Inclined ASDIC) a long-range sidescan-sonar system, provided broad-scale imagery of deep waters within the U.S. Exclusive Economic Zone (EEZ). In the early 1990's, research emphasis shifted...
Authors
J. F. Denny, W. C. Schwab, D.C. Twichell, T.F. O’Brien, W. W. Danforth, D. S. Foster, E. Bergeron, C.W. Worley, B.J. Irwin, B. Butman, P. C. Valentine, W. E. Baldwin, R.A. Morton, E.R. Thieler, D.R. Nichols, B.D. Andrews
Introduction--Subduction's sharpest arrow Introduction--Subduction's sharpest arrow
No abstract available.
Authors
J.C. Eichelberger
Debris flow hazards mitigation--Mechanics, prediction, and assessment Debris flow hazards mitigation--Mechanics, prediction, and assessment
These proceedings contain papers presented at the Fourth International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment held in Chengdu, China, September 10-13, 2007. The papers cover a wide range of topics on debris-flow science and engineering, including the factors triggering debris flows, geomorphic effects, mechanics of debris flows (e.g., rheology