HR: 14:25h
AN: V52E-04    [PDF]
TI: Interpretation of Gravity Gradients Produced by Magmatic Intrusions Using Elastic- and Viscoelastic-Gravitational Deformation Models
AU: * Fernandez, J
EM: jose_fernandez@mat.ucm.es
AF: Instituto de AstronomĦa y Geodesia (CSIC-UCM), Facultad de Ciencias Matem ticas,Ciudad Universitaria,Plaza de Ciencias 3., Madrid, 28040 Spain
AU: Tiampo, K F
EM: ktiampo@uwo.ca
AF: Dept. of Earth Sciences, University of Western Ontario, London, ON o Canada
AU: Rundle, J B
EM: rundle@physics.ucdavis.edu
AF: Center for Computational Science and Engineering and Department of Physics, University of California, One Shields Avenue, Davis, CA 95616-8677 United States
AU: Jentzsch, G
AF: Institute for Geosciences, FSU Jena, Burgweg 11, Jena, D-07749 Germany
AB: A method for the computation and interpretation of time-dependent potential and gravity changes and gravity gradients produced by magmatic intrusions in a layered elastic- and viscoelastic-gravitational medium is presented. The model assumes a plane medium geometry, which consists of welded layers overlying a half-space. Every layer or the bottom half-space can be considered either elastic or allowed to relax. The intrusion is treated as a point source and can be located in any of the layers or in the half-space. The model allows to compute geometric and orthometric vertical displacements as well as surface, free-air and Bouguer free-air corrected gravity changes. We can compute the corresponding gravity gradients. We present several examples of theoretical computations and study different types of geometric and orthometric gravity gradients. The results show that these gradients can be an useful tool to obtain information on the dynamics of the injection and post-injection processes, in particular detecting new magma intrusion or changes in the depth of the source. We also present the results of the application of the methodology to Mayon volcano, Philippines, and to Campi Flegrei, Italy.
DE: 1204 Control surveys
DE: 1299 General or miscellaneous
DE: 3210 Modeling
DE: 8419 Eruption monitoring (7280)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting