HR: 0800h
AN: G51A-0065    [Abstracts]
TI: Mount Etna 1993-1997 Inflation: Source Inference Based on Geodetic Data Modelling
AU: Bonaccorso, A
EM: bonaccorso@ct.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Piazza Roma 2, Catania, CT 95123 Italy
AU: Bonafede, M
EM: bonafede@ibogf.df.unibo.it
AF: Universit\`a degli Studi di Bologna, Dipartimento di Fisica, Settore Geofisica, Viale Berti Pichat 8, Bologna, BO 40127 Italy
AU: Cianetti, S
EM: spina@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Roma, RM 00143 Italy
AU: * Giunchi, C
EM: giunchi@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Roma, RM 00143 Italy
AU: Trasatti, E
EM: trasatti@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Roma, RM 00143 Italy
AB: Since 1993 geodetic data obtained by different techniques (GPS, EDM, SAR, levelling) detected a consistent inflation of the Mount Etna volcano. The inflation, culminated with the 1998-2001 strong explosive activity from summit craters and recent 2001 and 2002 flank eruptions, may be interpreted by magma ascent and re-filling of the volcanic plumbing system and reservoirs. We model the 1993-97 EDM and GPS data by 3D pressurized sources to infer the position and dimension of the magma reservoir. We perform analytical inversions of the observed deformation using both spheroidal and ellipsoidal sources embedded in a homogeneous elastic half-space and by applying different inversion methods. Solutions for these types of sources show evidence of a magma body located 6 km beneath the summit craters. Further, more refined and realistic models, based on the results of the analytical inversions, are developed using the Finite Element technique. This method allows to study the effect on the predicted deformation of both Mt. Etna 3D topography and its heterogeneous elastic structure as deduced by recent seismic tomography. The deformation predicted by all the models considered shows a general agreement with the 1993-1997 data, suggesting the primary role of a pressure source. However, major discrepancies are located in the SE sector; these discrepancies cannot be recovered by models characterized either by the real topography or by elastic heterogeneities. This result confirms that tectonic structures and rheological properties may control the observed deformation in the SE sector of Mt Etna. Gravitational sliding along detachment surfaces may have contributed to amplify the deformation during the inflation.
DE: 8414 Eruption mechanisms
DE: 8499 General or miscellaneous
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting