The SEA-CALIPSO volcano imaging experiment at Montserrat: plans, campaigns at sea and on land, scientific results, and lessons learned
Published:January 01, 2014
B. Voight, R. S. J. Sparks, E. Shalev, T. Minshull, M. Paulatto, C. Annen, C. Kenedi, J. Hammond, T. J. Henstock, L. Brown, E. Kiddle, P. Malin, G. Mattioli, C. Ammon, E. Arias-Dotson, A. Belousov, K. Byerly, L. Carothers, A. Clarke, S. Dean, L. Ellett, D. Elsworth, D. Hidayat, R. A. Herd, M. Johnson, A. Lee, V. Miller, B. Murphy, C. Peirce, G. Ryan, S. Saldana, C. Snelson, R. Stewart, R. Syers, J. Taron, J. Trofimovs, C. Widiwijayanti, S. R. Young, W. Zamora, 2014. "The SEA-CALIPSO volcano imaging experiment at Montserrat: plans, campaigns at sea and on land, scientific results, and lessons learned", The Eruption of Soufrière Hills Volcano, Montserrat from 2000 to 2010, G. Wadge, R. E. A. Robertson, B. Voight
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Since 1995 the eruption of the andesitic Soufrière Hills Volcano (SHV), Montserrat, has been studied in substantial detail. As an important contribution to this effort, the Seismic Experiment with Airgunsource-Caribbean Andesitic Lava Island Precision Seismo-geodetic Observatory (SEA-CALIPSO) experiment was devised to image the arc crust underlying Montserrat, and, if possible, the magma system at SHV using tomography and reflection seismology. Field operations were carried out in October–December 2007, with deployment of 238 seismometers on land supplementing seven volcano observatory stations, and with an array of 10 ocean-bottom seismometers deployed offshore. The RRS James Cook on NERC cruise JC19 towed a tuned airgun array plus a digital 48-channel streamer on encircling and radial tracks for 77 h about Montserrat during December 2007, firing 4414 airgun shots and yielding about 47 Gb of data. The main objecctives of the experiment were achieved. Preliminary analyses of these data published in 2010 generated images of heterogeneous high-velocity bodies representing the cores of volcanoes and subjacent intrusions, and shallow areas of low velocity on the flanks of the island that reflect volcaniclastic deposits and hydrothermal alteration. The resolution of this preliminary work did not extend beyond 5 km depth. An improved three-dimensional (3D) seismic velocity model was then obtained by inversion of 181 665 first-arrival travel times from a more-complete sampling of the dataset, yielding clear images to 7.5 km depth of a low-velocity volume that was interpreted as the magma chamber which feeds the current eruption, with an estimated volume 13 km3. Coupled thermal and seismic modelling revealed properties of the partly crystallized magma. Seismic reflection analyses aimed at imaging structures under southern Montserrat had limited success, and suggest subhorizontal layering interpreted as sills at a depth of between 6 and 19 km. Seismic reflection profiles collected offshore reveal deep fans of volcaniclastic debris and fault offsets, leading to new tectonic interpretations. This chapter presents the project goals and planning concepts, describes in detail the campaigns at sea and on land, summarizes the major results, and identifies the key lessons learned.
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The Eruption of Soufrière Hills Volcano, Montserrat from 2000 to 2010
The 1995 to present eruption of Soufrière Hills Volcano on Montserrat is one of the most important and best-studied eruptions of an explosive andesitic volcano. This volume presents scientific findings from the period between 2000 and 2010; it follows on from Memoir 21, which focused on the early years of activity between 1995 and 1999. In addition to descriptions and analysis of the growth, collapse and explosions associated with lava domes, there are papers on the deformation of the volcano caused by the deep magma, the petrology and geochemistry of the lavas and associated gases. Of particular note are: an overview of the insights into the deep structure of the volcano that resulted from a major international seismic tomography experiment; and an analysis of the quantitative risk assessment process that has run now for most of the eruption, the longest such continuous assessment in the world.