Publications
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Revised ages for tuffs of the Yellowstone Plateau volcanic field: Assignment of the Huckleberry Ridge Tuff to a new geomagnetic polarity event
40Ar/39Ar ages were determined on the three major ash-flow tuffs of the Yellowstone Plateau volcanic field in the region of Yellowstone National Park in order to improve the precision of previously determined ages. Total-fusion and incremental- heating ages of sanidine yielded the following mean ages: Huckleberry Ridge Tuff—2.059 ± 0.004 Ma; Mesa Falls Tuff— 1.285 ± 0.004 Ma; and Lava Creek Tuff—
Authors
M. A. Lanphere, D. E. Champion, R. L. Christiansen, G. A. Izett, J.D. Obradovich
Mechanics of debris flows and debris-laden flash floods
A new mathematical model developed to predict behavior of debris flows and avalanches also holds promise for predicting behavior of debris-laden flash floods. The model assumes that debris flows behave as mixtures of interacting Newtonian fluids and Coulomb solids. Solid and fluid constituents obey three-dimensional mass and momentum balances, which are summed and depth-integrated to yield equatio
Authors
Richard M. Iverson, Roger P. Denlinger
Sequence stratigraphy of a South Florida carbonate ramp and bounding siliciclastics (late Miocene-Pliocene)
In southern peninsular Florida, a late-early to early-late Pliocene carbonate ramp (Ochopee Limestone Member of the Tamiami Formation) is sandwiched between underlying marine siliciclastics of the late Miocene to early Pliocene Peace River Formation and an overlying late Pliocene unnamed sand. At least three depositional sequences (DS1, DS2, and DS3), of which two contain condensed sections, are r
Authors
Kevin J. Cunningham, David Bukry, T. Sato, John A. Barron, Laura A. Guertin, Ronald S. Reese
Volcanism in national parks: summary of the workshop convened by the U.S. Geological Survey and National Park Service, 26-29 September 2000, Redding, California
Spectacular volcanic scenery and features were the inspiration for creating many of our national parks and monuments and continue to enhance the visitor experience today (Table 1). At the same time, several of these parks include active and potentially active volcanoes that could pose serious hazards - earthquakes, mudflows, and hydrothermal explosions, as well as eruptions - events that would pro
Authors
Steven R. Brantley, Lindsay McClelland
Origin, extent, and thickness of quaternary geologic units in the Willamette Valley, Oregon
Stratigraphic and chronologic information collected for Quaternary deposits in the Willamette Valley, Oregon, provides a revised stratigraphic framework that serves as a basis for a 1:250,000-scale map, as well as for thickness estimates of widespread Quaternary geologic units. We have mapped 11 separate Quaternary units that are differentiated on the basis of stratigraphic, topographic, pedogenic
Authors
Jim E. O'Connor, Andrei M. Sarna-Wojcicki, Karl C. Wozniak, Danial J. Polette, Robert J. Fleck
The Quaternary and Pliocene Yellowstone Plateau volcanic field of Wyoming, Idaho, and Montana
This region of Yellowstone National Park has been the active focus of one of the Earth's largest magmatic systems for more than 2 million years. The resulting volcanism has been characterized by the eruption of voluminous rhyolites and subordinate basalts but virtually no lavas of intermediate composition. The magmatic system at depth remains active and drives the massive hydrothermal circulation
Authors
Robert L. Christiansen
Volcano hazards in the Three Sisters region, Oregon
Three Sisters is one of three potentially active volcanic centers that lie close to rapidly growing communities and resort areas in Central Oregon. Two types of volcanoes exist in the Three Sisters region and each poses distinct hazards to people and property. South Sister, Middle Sister, and Broken Top, major composite volcanoes clustered near the center of the region, have erupted repeatedly ove
Authors
William E. Scott, R. M. Iverson, S. P. Schilling, B.J. Fisher
Bathymetry and selected perspective views of Crater Lake, Oregon
No abstract available
Authors
J.V. Gardner, Peter Dartnell, Laurent Hellequin, C. R. Bacon, L. A. Mayer, M. W. Buktenica
Geologic studies in Alaska by the U.S. Geological Survey, 1999
The collection of nine papers that follow continue the series of U.S. Geological Survey (USGS) investigative reports in Alaska under the broad umbrella of the geologic sciences. The series presents new and sometimes preliminary findings that are of interest to earth scientists in academia, government, and industry; to land and resource managers; and to the general public. Reports presented in Geol
Progress made in understanding Mount Rainier's hazards
At 4392 m high, glacier-clad Mount Rainier dominates the skyline of the southern Puget Sound region and is the centerpiece of Mount Rainier National Park. About 2.5 million people of the greater Seattle-Tacoma metropolitan area can see Mount Rainier on clear days, and 150,000 live in areas swept by lahars and floods that emanated from the volcano during the last 6,000 years (Figure 1). These lahar
Authors
T. W. Sisson, J.W. Vallance, P. T. Pringle
Distributed shear of subglacial till due to Coulomb slip
In most models of the flow of glaciers on till beds, it has been assumed that till behaves as a viscoplastic fluid, despite contradictory evidence from laboratory studies. In accord with this assumption, displacement profiles measured in subglacial till have been fitted with viscoplastic models by estimating the stress distribution. Here we present a model that illustrates how observed displacemen
Authors
Neal R. Iverson, Richard M. Iverson
Determining the stress regime in a volcanic edifice from igneous intrusions and deformation measurements
No abstract available.
Authors
Michael P. Poland