Publications
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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
Seismicity and deformation induced by magma accumulation at three basaltic volcanoes
We analyzed the evolution of volcano‐tectonic (VT) seismicity and deformation at three basaltic volcanoes (Kilauea, Mauna Loa, Piton de la Fournaise) during phases of magma accumulation. We observed that the VT earthquake activity displays an accelerating evolution at the three studied volcanoes during the time of magma accumulation. At the same times, deformation rates recorded at the summit of K
Authors
O. Lengline, David Marsan, J.-L. Got, Virginie Pinel, Valerie Ferrazzini, Paul G. Okubo
A landslide in Tertiary marine shale with superheated fumaroles, Coast Ranges, California
In August 2004, a National Forest fire crew extinguished a 1.2 ha fire in a wilderness area ~40 km northeast of Santa Barbara, California. Examination revealed that the fire originated on a landslide dotted with superheated fumaroles. A 4 m borehole punched near the hottest (262 °C) fumarole had a maximum temperature of 307 °C. Temperatures in this borehole have been decreasing by ~0.1 °C/d, altho
Authors
Robert H. Mariner, Scott A. Minor, A. King, J.R. Boles, Karl S. Kellogg, William C. Evans, Gary Landis, A.G. Hunt, Christy B. Till
Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua
Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active volcanoes in Central America. The soil temperatures were measured
Authors
S.C.P. Pearson, C.B. Connor, W. E. Sanford
Towards continuous 4D microgravity monitoring of volcanoes
Four-dimensional or time-lapse microgravity monitoring has been used effectively on volcanoes for decades to characterize the changes in subsurface volcanic systems. With measurements typically lasting from a few days to weeks and then repeated a year later, the spatial resolution of theses studies is often at the expense of temporal resolution and vice versa. Continuous gravity studies with one t
Authors
Glyn Williams-Jones, Hazel Rymer, Guillaume Mauri, Joachim Gottsmann, Michael P. Poland, Daniele Carbone
Deciphering landslide behavior using large-scale flume experiments
Landslides can be triggered by a variety of hydrologic events and they can exhibit a wide range of movement dynamics. Effective prediction requires understanding these diverse behaviors. Precise evaluation in the field is difficult; as an alternative we performed a series of landslide initiation experiments in the large-scale, USGS debris-flow flume. We systematically investigated the effects of t
Authors
Mark E. Reid, Richard M. Iverson, Neal R. Iverson, Richard G. LaHusen, Dianne L. Brien, Matthew Logan
Database for the Geologic Map of Upper Eocene to Holocene Volcanic and Related Rocks of the Cascade Range, Oregon
Since 1979, Earth scientists of the Geothermal Research Program of the U.S. Geological Survey have carried out multidisciplinary research in the Cascade Range. The goal of this research is to understand the geology, tectonics, and hydrology of the Cascades in order to characterize and quantify geothermal resource potential. A major goal of the program is compilation of a comprehensive geologic map
Authors
Kathryn Nimz, David W. Ramsey, David R. Sherrod, James G. Smith
Long Valley Observatory
The ~300-year-old lava on Paoha Island in Mono Lake was produced by the most recent eruption in the Long Valley Caldera area in east-central California. The Long Valley Caldera was formed by a massive volcanic eruption 760,000 years ago. The region is monitored by the Long Valley Observatory (LVO), one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and p
Authors
Dina Y. Venezky, David Hill
Yellowstone Volcano Observatory
Eruption of Yellowstone's Old Faithful Geyser. Yellowstone hosts the world's largest and most diverse collection of natural thermal features, which are the surface expression of magmatic heat at shallow depths in the crust. The Yellowstone system is monitored by the Yellowstone Volcano Observatory (YVO), a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and the Univ
Authors
Dina Y. Venezky, Jacob Lowenstern