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Dynamics of Kilauea Volcano Dynamics of Kilauea Volcano

One of the longest volcanic eruptions in recorded history began in 1983. Lava flows from Kilauea have since added 120 hectares of new land to the island of Hawaii and covered 100 square kilometres. Kilauea is one of the most thoroughly studied volcanoes in the world. That scrutiny is helping scientists to understand how volcanoes work and to predict where other destructive eruptions...
Authors
J.J. Dvorak, Carl Johnson, Robert I. Tilling

Gravity-driven groundwater flow and slope failure potential: 2. Effects of slope morphology, material properties, and hydraulic heterogeneity Gravity-driven groundwater flow and slope failure potential: 2. Effects of slope morphology, material properties, and hydraulic heterogeneity

Hillslope morphology, material properties, and hydraulic heterogeneities influence the role of groundwater flow in provoking slope instability. We evaluate these influences quantitatively by employing the elastic effective stress model and Coulomb failure potential concept described in our companion paper (Iverson and Reid, this issue). Sensitivity analyses show that of four...
Authors
Mark E. Reid, Richard M. Iverson

Morphology of the island of Hawaii Morphology of the island of Hawaii

Digital elevation data for the island of Hawaii from the U.S. Geographical Survey gridded at 30 m spacing was used to generate a slope map, a shaded relief map, and plots that compare slope and elevation for each of the five volcanoes that compose the island.These computer- generated products are useful in analyzing the morphology of the sland. The volcanoes become steeper with...
Authors
James G. Moore, Robert K. Mark

Partially melted granodiorite and related rocks ejected from Crater Lake caldera, Oregon Partially melted granodiorite and related rocks ejected from Crater Lake caldera, Oregon

Blocks of medium-grained granodiorite to 4 m, and minor diabase, quartz diorite, granite, aplite and granophyre, are common in ejecta of the ∼6,900 yr BP caldera-forming eruption of Mount Mazama. The blocks show degrees of melting from 0–50 vol%. Because very few have adhering juvenile magma, it is thought that the blocks are fragments of the Holocene magma chamber’s walls. Primary...
Authors
Charles R. Bacon

Water, CO2, Cl, and F in melt inclusions in phenocrysts from three Holocene explosive eruptions, Crater Lake, Oregon Water, CO2, Cl, and F in melt inclusions in phenocrysts from three Holocene explosive eruptions, Crater Lake, Oregon

Rare melt inclusions ~ 100 μm in diameter trapped near the boundaries of corroded patchy zones in plagioclase phenocrysts from Plinian pumice of three Holocene eruptions were analyzed by IR spectroscopy for molecular H2O, OH groups, and CO2and by electron microprobe for Cl and F. The three rhyodacitic eruptions, each of which began with a Plinian phase, occurred over ~200 yr. The Llao...
Authors
C. R. Bacon, Sally Newman, E. Stolper

Preliminary geologic map of the Cold Bay and False Pass quadrangles, Alaska Peninsula Preliminary geologic map of the Cold Bay and False Pass quadrangles, Alaska Peninsula

This map of the Cold Bay and False Pass 1:250,000-scale quadrangles on the Alaska Peninsula is a compilation based in part on the mapping conducted as part of the Alaska Mineral Resource Assessment Program (AMRAP) and the Geothermal Energy Program. Field studies by the authors began as early as 1973 in the quadrangles, but systematic mapping was not begun until 1988. Systematic mapping...
Authors
Frederic H. Wilson, Thomas P. Miller, Robert L. Detterman

Garnet/high-silica rhyolite trace element partition coefficients measured by ion microprobe Garnet/high-silica rhyolite trace element partition coefficients measured by ion microprobe

Garnet/liquid trace element partition coefficients have been measured in situ by ion microprobe in a rhyolite from Monache Mountain, California. Partition coefficients are reported for La, Ce, Nd, Sm, Dy, Er, Yb, Sc, Ti, V, Cr, Sr, Y, and Zr. The in situ analyses avoid the problem of contamination of the garnet phase by trace element-rich accessory minerals encountered in traditional...
Authors
Thomas W. Sisson, Charles R. Bacon

A postulated new source for the White River Ash, Alaska: A section in Geologic studies in Alaska by the US. Geological Survey, 1990 A postulated new source for the White River Ash, Alaska: A section in Geologic studies in Alaska by the US. Geological Survey, 1990

The White River Ash (Lerbekmo and others, 1968), product of two of the most voluminous pyroclastic eruptions in North America in the past 2,000 yr, blankets much of the Yukon Terrtory, Canada, and a small part of adjoining eastern Alaska. Lerbekmo and Campbell (1969) narrowed the source of the ash to an area northeast of the Mt. Bona-Mt. Churchill massif in the St. Elias Mountains of...
Authors
Robert G. McGimsey, Donald H. Richter, Gregory D. DuBois, T. P. Miller
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