Abstract
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,
VOL. 13,
Q01014,
18 PP., 2012
doi:10.1029/2011GC003892
Magma chamber properties from integrated seismic tomography and thermal modeling at Montserrat
- We image an active magma chamber with seismic tomography in unique detail
- Integration of tomography with thermal models gives new insight into magmatism
- Shallow magma chambers beneath arc volcanoes are transient and short lived
Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
National Oceanography Centre, Southampton, University of Southampton, European Way, Southampton SO14 3ZH, UK
Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
National Oceanography Centre, Southampton, University of Southampton, European Way, Southampton SO14 3ZH, UK
Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
National Oceanography Centre, Southampton, University of Southampton, European Way, Southampton SO14 3ZH, UK
Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK
Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
It is widely believed that andesitic magmas erupted at arc-volcanoes are stored in shallow reservoirs prior to eruption, but high-resolution images of focused regions of magma in the shallow crust are rare. We integrate seismic tomography with numerical models of magma chamber growth to constrain the magma chamber beneath Soufrière Hills Volcano, Montserrat. Our approach reveals the characteristics and dynamics of the magmatic system with a level of detail that no single method has yet achieved. The integrated analysis suggests that a magma chamber of 13 km3 with over 30% melt fraction formed between 5.5 and at least 7.5 km depth, a significantly higher melt fraction than inferred from the seismic data alone. The magma chamber may have formed by incremental sill intrusion over a few thousand years and is likely to be a transient, geologically short-lived feature. These volume and geometry estimates are critical parameters to model eruption dynamics, which in turn are key to hazard assessment and eruption forecasting.
Received 23 September 2011; accepted 12 December 2011; published 20 January 2012.
Citation: (2012), Magma chamber properties from integrated seismic tomography and thermal modeling at Montserrat, Geochem. Geophys. Geosyst., 13, Q01014, doi:10.1029/2011GC003892.
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