Publications
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Evolution of melt-vapor surface tension in silicic volcanic systems: Experiments with hydrous melts
We evaluate the melt‐vapor surface tension (σ) of natural, water‐saturated dacite melt at 200 MPa, 950–1055°C, and 4.8–5.7 wt % H2O. We experimentally determine the critical supersaturation pressure for bubble nucleation as a function of dissolved water and then solve for σ at those conditions using classical nucleation theory. The solutions obtained give dacite melt‐vapor surface tensions that v
Authors
M. Mangan, T. Sisson
Ion microprobe measurement of strontium isotopes in calcium carbonate with application to salmon otoliths
The ion microprobe has the capability to generate high resolution, high precision isotopic measurements, but analysis of the isotopic composition of strontium, as measured by the 87Sr/86Sr ratio, has been hindered by isobaric interferences. Here we report the first high precision measurements of 87Sr/86Sr by ion microprobe in calcium carbonate samples with moderate Sr concentrations. We use the hi
Authors
P.K. Weber, C. R. Bacon, I.D. Hutcheon, B. L. Ingram, Joseph L. Wooden
The ubiquitous nature of accessory calcite in granitoid rocks: Implications for weathering, solute evolution, and petrogenesis
Calcite is frequently cited as a source of excess Ca, Sr and alkalinity in solutes discharging from silicate terrains yet, no previous effort has been made to assess systematically the overall abundance, composition and petrogenesis of accessory calcite in granitoid rocks. This study addresses this issue by analyzing a worldwide distribution of more than 100 granitoid rocks. Calcite is found to be
Authors
A. F. White, M. S. Schulz, J. B. Lowenstern, D.V. Vivit, T.D. Bullen
Acoustic Flow Monitor System - User Manual
INTRODUCTION
The Acoustic Flow Monitor (AFM) is a portable system that was designed by the U.S. Geological Survey Cascades Volcano Observatory to detect and monitor debris flows associated with volcanoes. It has been successfully used internationally as part of real-time warning systems in valleys threatened by such flows (Brantley, 1990; Marcial and others, 1996; Lavigne and others, 2000). The
Authors
Richard LaHusen
2004 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory
No abstract available.
Authors
Christina A. Neal, Robert G. McGimsey, Jim Dixon, Dmitry Melnikov
An assessment of volcanic threat and monitoring capabilities in the United States: Framework for a National Volcano Early Warning System
Executive SummaryNVEWS – a National Volcano Early Warning System – is being formulated by the Consortium of U.S. Volcano Observatories (CUSVO) to establish a proactive, fully integrated, national-scale monitoring effort that ensures the most threatening volcanoes in the United States are properly monitored in advance of the onset of unrest and at levels commensurate with the threats posed. Volcani
Authors
John W. Ewert, Marianne Guffanti, Thomas L. Murray
Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska
High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11 geographically distrib
Authors
Andrew T. Calvert, Richard B. Moore, Robert G. McGimsey
2003 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory
The Alaska Volcano Observatory (AVO) monitors the more than 40 historically active volcanoes of the Aleutian Arc. Of these, 24 were considered monitored in real time with short-period seismic instrument networks as of the end of 2003. The AVO core monitoring program also includes daily analysis of satellite imagery, observation over flights, and compilation of pilot reports and reports from local
Authors
Robert G. McGimsey, Christina A. Neal, Olga Girina
Magma generation at a large, hyperactive silicic volcano (Taupo, New Zealand) revealed by U-Th and U-Pb systematics in zircons
Young (<∼65 ka) explosive silicic volcanism at Taupo volcano, New Zealand, has involved the development and evacuation of several crustal magmatic systems. Up to and including the 26·5 ka 530 km3 Oruanui eruption, magmatic systems were contemporaneous but geographically separated. Subsequently they have been separated in time and have vented from geographically overlapping areas. Single-crystal (s
Authors
B. L. A. Charlier, C. J. N. Wilson, J. B. Lowenstern, S. Blake, P.W. van Calsteren, J.P. Davidson
Diatoms as indicators of late Holocene freshwater flow variation in the San Francisco Bay estuary, central California, U.S.A
No abstract available.
Authors
Scott W. Starratt
The ongoing Pu'u 'O'o-Kupaianaha eruption of Kilauea Volcano, Hawai'i
No abstract available.
Authors
Christina Heliker, Steven R. Brantley
Oligocene and earliest Miocene diatom biostratigraphy of ODP leg 199 site 1220, equatorial Pacific
Completion of studies on material collected during Ocean Drilling Program Leg 199 at Site 1220 in the equatorial Pacific allows calibration of the ranges of >35 stratigraphically important diatoms to paleomagnetic stratigraphy for the Oligocene and earliest Miocene (~33.5–21.5 Ma). The taxonomy of these taxa is reviewed, and age estimates of their first and last occurrences are compiled. The diato
Authors
John A. Barron, Elisabeth Fourtanier, S. M. Bohaty