J. Sparks

Brigham and Women's Hospital

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Ralph A. Stephen

Woods Hole Oceanographic Institution

Herbert E. Huppert

University of Cambridge

R. Stephen

University of Bristol

J. M. Rhodes

University of Massachusetts Amherst

J. S. Turner

University of Connecticut

R. Steven

University of Bristol

Daniel Bideau

Centre National de la Recherche Scientifique

S. R. Young

Lancaster University

M V Stasiuk

Geological Survey of Canada

John P. Lockwood

University of Hawaii at Hilo

Cooperative Institutions

United States Geological Survey

University of Bristol

Montserrat Volcano Observatory

University of Cambridge

Woods Hole Oceanographic Institution

Pennsylvania State University

University of Washington

The University of Tokyo

Volcano Corporation (United States)

University of Hawaii System

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Cooling and crystallization at an inclined plane

Earth and Planetary Science Letters (1986)

Herbert E. Huppert Ralph A. Stephen J. Sparks J. Richard Wilson Mark A. Hallworth

Stratification (seeds)

Temperature Gradient

10.1016/0012-821x(86)90188-3

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Citations (44)

Long-term compositional and eruptive behavior of Mauna Loa Volcano: Evidence from prehistoric caldera basalts

J. Sparks

Caldera

Petrogenesis

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Citations (2)

Transtensional deformation of Montserrat revealed by shear wave

Alan F. Baird J. M. Kendall Ralph A. Stephen J. Sparks Brian Baptie

a b s t r a c t Here we investigate seismic anisotropy of the upper crust in the vicinity of Soufriere Hills volcano using shear wave splitting (SWS) analysis from volcano-tectonic (VT) events. Soufriere Hills, which is located on the island of Montserrat in the Lesser Antilles, became active in 1995 and has been erupting ever since with five major phases of extrusive activity. We use data recorded on a network of seismometers between 1996 and 2007 partially spanning three extrusive phases. Shear-wave splitting in the crust is often assumed to be controlled either by structural features, or by stress aligned cracks. In such a case the polarization of the fast shear wave (φ) would align parallel to the strike of the structure, or to the maximum compressive stress direction. Previous studies analyzing SWS in the region using regional earthquakes observed temporal variations in φ which were interpreted as being caused by stress perturbations associated with pressurization of a dyke. Our analysis, which uses much shallower sources and thus only samples the anisotropy of the upper few kilometres of the crust, shows no clear temporal variation. However, temporal effects cannot be ruled out, as large fluctuations in the rate of VT events over the course of the study period as well as changes in the seismic network configuration make it difficult to assess. Average delay times of approximately 0.2 s, similar in magnitude to those reported for much deeper slab events, suggest that the bulk of the anisotropy is in the shallow crust. We observe clear spatial variations in anisotropy which we believe are consistent with structurally controlled anisotropy resulting from a left-lateral transtensional array of faults which crosses the volcanic complex.

Extrusive

Shear wave splitting

Seismometer

Stress field

S-wave

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Influence of cooling on lava-flow dynamics: Comment and Reply

Geology (1994)

John R. Lister Ross C. Kerr M V Stasiuk Claude Jaupart R. Stephen

Research Article| January 01, 1994 Influence of cooling on lava-flow dynamics: Comment and Reply John R. Lister; John R. Lister 1Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, Silver Street, Cambridge, CB3 9EW, United Kingdom Search for other works by this author on: GSW Google Scholar Ross C. Kerr; Ross C. Kerr 2Research School of Earth Sciences, Australian National University, Canberra, A. C. T. 0200, Australia Search for other works by this author on: GSW Google Scholar Mark V. Stasiuk; Mark V. Stasiuk 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar Claude Jaupart; Claude Jaupart 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar R. Stephen; R. Stephen 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar J. Sparks J. Sparks 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar Geology (1994) 22 (1): 93–94. https://doi.org/10.1130/0091-7613(1994)022<0093:IOCOLF>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation John R. Lister, Ross C. Kerr, Mark V. Stasiuk, Claude Jaupart, R. Stephen, J. Sparks; Influence of cooling on lava-flow dynamics: Comment and Reply. Geology 1994;; 22 (1): 93–94. doi: https://doi.org/10.1130/0091-7613(1994)022<0093:IOCOLF>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract No abstract available This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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10.1130/0091-7613(1994)022<0093:iocolf>2.3.co;2

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Citations (9)

Prototype PBO instrumentation of CALIPSO project captures world‐record lava dome collapse on Montserrat Volcano

Eos (2004)

G. S. Mattioli S. R. Young B. Voight R. Steven J. Sparks

This article is an update on the status of an innovative new project designed to enhance generally our understanding of andesitic volcano eruption dynamics and, specifically the monitoring and scientific infrastructure at the active Soufrière Hills Volcano (SHV), Montserrat. The project has been designated as the Caribbean Andesite Lava Island Precision Seismo‐geodetic Observatory known as CALIPSO. Its purpose is to investigate the dynamics of the entire SHV magmatic system using an integrated array of specialized instruments in four strategically located ∼200‐m‐deep boreholes in concert with several shallower holes and surface sites. The project is unique, as it represents the first, and only such borehole volcano‐monitoring array deployed at an andesitic stratovolcano.

Stratovolcano

Lava dome

10.1029/2004eo340001

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Citations (26)

A laboratory simulation of pyroclastic flows down slopes

Journal of Volcanology and Geothermal Research (1986)

Herbert E. Huppert J. S. Turner Steven N. Carey Ralph A. Stephen J. Sparks

Neutral buoyancy

Gravity current

10.1016/0377-0273(86)90054-5

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Citations (57)

The origins of granites

Nature (1987)

Ralph A. Stephen J. Sparks Herbert E. Huppert

10.1038/330207a0

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Citations (2)

Prototype PBO instrumentation of CALIPSO project captures world‚ a record lava dome collapse on Montserrat Volcano

G. S. Mattioli S. R. Young B. Voight R. Steven J. Sparks

Dome (geology)

Lava dome

Instrumentation

Source

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Disruption of the Mauna Loa Magma System by the 1868 Hawaiian Earthquake: Geochemical Evidence

Science (1987)

Robert I. Tilling J. M. Rhodes J. Sparks John P. Lockwood Peter W. Lipman

To test whether a catastrophic earthquake could affect an active magma system, mean abundances (adjusted for "olivine control") of titanium, potassium, phosphorus, strontium, zirconium, and niobium of historic lavas erupted from Mauna Loa Volcano, Hawaii, after 1868 were analyzed and were found to decrease sharply relative to lavas erupted before 1868. This abrupt change in lava chemistry, accompanied by a halved lava-production rate for Mauna Loa after 1877, is interpreted to reflect the disruptive effects of a magnitude 7.5 earthquake in 1868. This interpretation represents a documentable case of changes in magmatic chemical variations initiated or accelerated by a major tectonic event.

10.1126/science.235.4785.196

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Citations (31)

Cooling and contamination of mafic and ultramafic magmas during ascent through continental crust

Earth and Planetary Science Letters (1985)

Herbert E. Huppert Ralph A. Stephen J. Sparks

Phenocryst

Magma chamber

Fractional crystallization (geology)

Ultramafic rock

10.1016/s0012-821x(85)80009-1

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Citations (378)