Comparison of Integrated Geodetic Data Models and Satellite Radar Interferograms to Infer Magma Storage During the 19911993 Mt. Etna Eruption

We compare the results obtained from the modelling of EDM, GPS, levelling and tilt data measured in the first part of the 19911993 eruption at Etna to the InSAR data acquired during the second part. The geodetic changes are very marked in the first half of the eruption and constrain a deflation source located at a few kilometers of depth ( 3 km b.s.l.), in agreement with other independent geophysical evidence. SAR data, available during the second part of the eruption, were analysed for different time intervals in the second part of the eruption. The interpretation of SAR interferograms reveals a large-scale but less marked deflation of the volcano that could be caused by a deeper source. This second source is in accord with a second deeper anomaly revealed by recent seismic investigations. The combination of geodetic data modelling and SAR images suggests a complex plumbing system composed at least of two possible storage regions located at different depths.

BEAUDUCEL, F., BRIOLE, P., and FROGER, J. L. (2000), Volcano-wide Fringes in ERS Synthetic Aperture Radar Interferograms of Etna (1992–1998): Deformation or Tropospheric E.ect, J. Geophys. Res. 105, 16,391–16,402.

BONACCORSO, A. (1996), A Dynamic Inversion for Modelling Volcanic Sources Through Ground Deformation Data (Etna 1991–1992), Geophys. Res. Lett. 23, 5, 451–454.

BONACCORSO, A., CAMPISI, O., GAMBINO , S., FALZONE, G., LAUDANI, G., PUGLISI, B., ROSSI, M.,VELARDITA, R., and VILLARI, L. (1994), Ground Deformation Modelling of Geodynamic Activity Associated with the 1991-1993 Etna Eruption, Acta Vulcanologia, 4, 87–96.

BUDETTA, G. and CARBONE, D. (1998), Temporal Variations in Gravity at Mt. Etna (Italy) Associated with 1989 and 1991 Eruptions, Bull. Volcanol. 59, 311–326.

CAYOL, V. and CORNETTE, F. H. (1998), E.ects of Topography on the Interpretation of the Deformation Field of Prominent Volcanoes — Application to Etna, Geophys. Res. Lett. 23, 1979–1982.

CHIARABBA, C., AMATO A., BOSCHI, E., and BARBERI, F. (2000), Recent Seismicity and Tomographic Modeling of the Mount Etna Plumbing System, J. Geophys. Res. 105/B5, 10923–10938.

CORSARO, R. and POMPILIO, M. (1998), Il contrasto di densita` tra magmi etnei e rocce incassanti: implicazioni sui meccanismi di risalita. In Progetto Etna: il vulcanismo dell’ Etna in rapporto al suo contesto regionale, Open File Report, IIV-CNR, Catania, 4/96, 27–32.

DAVIS, P. M. (1986), Surface Deformation due to In.ation of an Arbitrarily Oriented Triaxial Ellipsoidal Cavity in an Elastic Half-space, with Reference to Kilauea Volcano, J. Geophys. Res. 91, 7429–7438.

DELACOURT, C., BRIOLE, P., and ACHACHE, J. (1998), Tropospheric Corrections of SAR Interferograms with Strong topography. Application to Etna, Geophys. Res. Lett. 15, 2849–2852.

DVORACK, J. and DZURISIN, D. (1997), Volcano Geodesy: The Search for Magma Reservoirs and the Formation of Eruptive Vents, Rev. Geophysics 35, 3, 343–384.

Gabriel, A. K., Goldstein, R. M., and Zebker, H. A. (1989), Mapping Small Elevation Changes over Large Areas: Di.erential Interferometry, J. Geophys. Res. 94, 9183–9191.

LANARI, R., LUNDGREN, P., and SANSOSTI, E. (1998), Dynamic Deformation of Etna Volcano Observed by Satellite Radar Interferometry, Geophys. Res. Lett. 25, 10, 1541–1544.

MASSONET, D., BRIOLE, P., and ARNAUD, A. (1995), De.ation of Mount Etna Monitored by Spaceborne Radar Interferometry, Nature 375, 567–570.

MURRAY, J. B. and MOSS, J. (1994), Results of Levelling at Mount Etna: Nov. 21 – Dec. 8, 1993, 6 pp., Report for Osservatorio Vesuviano, Naples.

MURRU, M., MONTUORI, C., WYSS, M., and PRIVITERA, E. (1999), The Locations of Magma Chambers at Mt. Etna, Italy, Mapped by b-values, Geophys. Res. Lett. 26, 16, 2553–2556.

NUNNARI, G. and PUGLISI, G. (1994), The Global Positioning System as Useful Technique for Measuring Ground Deformations in Volcanic Areas, J. Volcanol. Geoth. Res. 61, 267–280.

RUSSO, G., GIBERTI, G., and SARTORIS, G. (1997), Numerical Modeling of Surface Deformation and Mechanical Stability of Vesuvius Volcano, Italy, J. Geophys. Res. 102, 24,785–24,800.

SARAO` , A., PANZA, G. F., PRIVITERA, E., and COCINA, O. (2001), Non-double Mechanisms in the Seismicity Preceding the 1991–1993 Etna Volcano Eruption, Geophys. J. Int. 145, 1–25.

WILLIAMS, C. A. and WADGE, G. (1998), The E.ects of Topography on Magma Chamber Deformation Models: Application to Mt. Etna and Radar Interferometry, Geophys. Res. Lett. 25, 1549–1552.

WILLIAMS, C. A. and WADGE, G. (2000), An Accurate and E.cient Method for Including the E.ects of Topography in Three-dimensional and Elastic Models of Ground Deformation with Applications to Radar Interferometry, J. Geophys. Res. 105, 8103–8120.

ZEBKER, H. A., ROSEN, P. A., GOLDSTEIN, R. M., GABRIEL, A., and WERNER, C. L. (1994), On the Derivation of Coseismic Displacement Fields Using Di.erential Radar Interferometry: The Landers Earthquake, J. Geophys. Res. 99, 19,617–19,634.