Effect of mechanical heterogeneity in arc crust on volcano deformation with application to Soufriere Hills Volcano, Montserrat, West Indies
| Autor: | R. Stephen J. Sparks, Stephanie Hautmann, Glen S. Mattioli, M.H. Strutt, Joachim Gottsmann, I. Selwyn Sacks |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Atmospheric Science
geography geography.geographical_feature_category Ecology Volcanic arc Paleontology Soil Science Geodetic datum Forestry Crust Rigidity (psychology) Magma chamber Aquatic Science Oceanography Seismic analysis Geophysics Volcano Space and Planetary Science Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Compressibility Geology Seismology Earth-Surface Processes Water Science and Technology |
| Popis: | [1] Analyses of volcano surface deformation are commonly based on models that assume mechanical homogeneity of rocks surrounding the causative pressure source. Here we present a detailed study that shows the differences in deduced surface deformation caused by source pressurization accounting for either mechanical homogeneity or mechanical heterogeneity of encasing rocks in a volcanic arc setting using finite element models. Accounting for crustal heterogeneity from seismic data, we test for a range of source geometries and intermediate crustal depths and explore the misfits of deduced source parameters from the two families of models. In the second part of this study, we test the results from the generic study against cGPS data from two deformation periods (the 2003–2005 ground inflation and the 2005–2007 ground deflation) at Soufriere Hills Volcano, Montserrat, West Indies, to inform on source parameters. Accounting for a variable crustal rigidity with depth as deduced by seismic analysis beneath Montserrat, we find the data to be best explained by pressurization and depressurization of a slightly prolate midcrustal magma chamber that is centered between 11.5 and 13 km below sea level, about 640 m NE of the active vent. Considering source dimension and source pressure changes, we demonstrate that magma compressibility and viscoelasticity of host rocks considerably affect dynamics in the midcrustal magmatic system of Soufriere Hills Volcano and need to be accounted for as first-order effects in geodetic data analyses and modeling. |
| Databáze: | OpenAIRE |
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