Publications
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Quaternary science reviews Pacific Basin tsunami hazards associated with mass flows in the Aleutian arc of Alaska
We analyze mass-flow tsunami generation for selected areas within the Aleutian arc of Alaska using results from numerical simulation of hypothetical but plausible mass-flow sources such as submarine landslides and volcanic debris avalanches. The Aleutian arc consists of a chain of volcanic mountains, volcanic islands, and submarine canyons, surrounded by a low-relief continental shelf above about
Authors
Christopher F. Waythomas, Philip Watts, Fengyan Shi, James T. Kirby
A field guide to Newberry Volcano, Oregon
Newberry Volcano is located in central Oregon at the intersection of the Cascade Range and the High Lava Plains. Its lavas range in age from ca. 0.5 Ma to late Holocene. Erupted products range in composition from basalt through rhyolite and cover ~3000 km2. The most recent caldera-forming eruption occurred ~80,000 years ago. This trip will highlight a revised understanding of the volcano's history
Authors
Robert A. Jenson, Julie M. Donnelly-Nolan, Daniele McKay
Improved constraints on the estimated size and volatile content of the Mount St. Helens magma system from the 2004–2008 history of dome growth and deformation
The history of dome growth and geodetic deflation during the 2004–2008 Mount St. Helens eruption can be fit to theoretical curves with parameters such as reservoir volume, bubble content, initial overpressure, and magma rheology, here assumed to be Newtonian viscous, with or without a solid plug in the conduit center. Data from 2004–2008 are consistent with eruption from a 10–25 km3 reservoir cont
Authors
Larry G. Mastin, Mike Lisowski, Evelyn Roeloffs, Nick Beeler
Precision leveling and geodetic GPS observations performed on Surtsey between 1967 and 2002
The load on the crust from the ~ 0.8 km3 of eruptive products of the Surtsey eruption is expected to lead to subsidence of the Surtsey island by sagging of the lithosphere, compaction of material, and slumping of the volcanic edifice. Immediately after the eruption ended in the summer of 1967 a levelling line was established across the island to monitor this expected subsidence. The line originall
Authors
Erik Sturkell, P. Einarsson, Halldor Geirsson, E. Tryggvason, James G. Moore, Rosa Ólafsdottir
The July-August 2008 hydrovolcanic eruption of Okmok Volcano, Umnak Island, Alaska
No abstract available
Authors
Christina A. Neal, Jessica F. Larsen, Janet Schaefer
A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions
During volcanic eruptions, volcanic ash transport and dispersion models (VATDs) are used to forecast the location and movement of ash clouds over hours to days in order to define hazards to aircraft and to communities downwind. Those models use input parameters, called “eruption source parameters”, such as plume height H, mass eruption rate Ṁ, duration D, and the mass fraction m63 of erupted debri
Authors
Larry G. Mastin, Marianne C. Guffanti, R. Servranckx, P. Webley, S. Barsotti, K. Dean, A. Durant, John W. Ewert, A. Neri, W.I. Rose, David J. Schneider, Lee Siebert, B. Stunder, G. Swanson, A. Tupper, A. Volentik, Christopher F. Waythomas
Modeling hazardous mass flows Geoflows09: Mathematical and computational aspects of modeling hazardous geophysical mass flows; Seattle, Washington, 9–11 March 2009
A recent workshop at the University of Washington focused on mathematical and computational aspects of modeling the dynamics of dense, gravity-driven mass movements such as rock avalanches and debris flows. About 30 participants came from seven countries and brought diverse backgrounds in geophysics; geology; physics; applied and computational mathematics; and civil, mechanical, and geotechnical e
Authors
Richard M. Iverson, Randall J. LeVeque
Isotopic constraints on the chemical evolution of geothermal fluids, Long Valley, CA
A spatial survey of the chemical and isotopic composition of fluids from the Long Valley hydrothermal system was conducted. Starting at the presumed hydrothermal upwelling zone in the west moat of the caldera, samples were collected from the Casa Diablo geothermal field and a series of monitoring wells defining a nearly linear, ~14 km long, west-to-east trend along the proposed fluid flow path (So
Authors
Shaun T. Brown, B. Mack Kennedy, Donald J. DePaolo, William C. Evans
Establishing major permeability controls in the Mak-Ban geothermal field, Philippines
Recent updating of the conceptual model of the Mak-Ban (Bulalo) geothermal field verified both structural and stratigraphic controls on permeability and connectivity in the reservoir. Two silicic units within the predominantly andesitic production zone were identified from borehole logs, core and drill cuttings. Whole rock chemical data and petrographic analysis confirmed two rhyolite units that c
Authors
Ronald O. Vicedo, James Stimac, Vilma T. Capuno, Jacob B. Lowenstern
Origin of meter-size granite basins in the southern Sierra Nevada, California
Meter-size granite basins are found in a 180-km belt extending south from the South Fork of the Kings River to Lake Isabella on the west slope of the southern Sierra Nevada, California. Their origin has long been debated. A total of 1,033 basins have been inventoried at 221 sites. The basins occur on bedrock granitic outcrops at a median elevation of 1,950 m. Median basin diameter among 30 of the
Authors
James G. Moore, Mary A. Gorden, Joel E. Robinson, Barry C. Moring
Steady and intermittent slipping in a model of landslide motion regulated by pore-pressure feedback
This paper studies a parsimonious model of landslide motion, which consists of the one-dimensional diffusion equation (for pore pressure) coupled through a boundary condition to a first-order ODE (Newton's second law). Velocity weakening of sliding friction gives rise to nonlinearity in the model. Analysis shows that solutions of the model equations exhibit a subcritical Hopf bifurcation in which
Authors
David G. Schaeffer, Richard M. Iverson