Source model for the 2001 flank eruption of Mt. Etna volcano

[1] Using interferometric synthetic aperture radar (InSAR) we constrain the deformation sources for the July–August 2001 flank eruption of Mt. Etna volcano, Italy. InSAR data from ascending and descending passes of the ERS2 satellite reveal a pattern of deformation that cannot be explained by a dike intrusion alone. In addition to a vertical dike beneath the south rift zone, the spatially large (10 km scale, 15–20 cm in range) negative range displacement lobes across the western (descending data) and eastern (ascending data) flanks require a nearly symmetric set of shallowly dipping normal faults to each side of the central dike. Complexity in the observed InSAR surface displacements constrains an additional dike intrusion beneath its NE flank. Long-term deformation of Etna's eastern and southern flanks is well established through field and InSAR observations. Therefore, the relative symmetry of motion beneath both the western and eastern flanks during the 2001 eruption is surprising. Our model of symmetric flank motion suggests that on the short time scales of a large dike intrusion volcanoes can deform differently from their long-term deformation.

[1]  R. Azzaro,et al.  Aseismic creep on faults and flank instability at Mount Etna volcano, Sicily , 1996, Geological Society, London, Special Publications.

[2]  Pierre Briole,et al.  Active spreading and regional extension at Mount Etna imaged by SAR interferometry , 2001 .

[3]  Shinji Toda,et al.  Evidence from the ad 2000 Izu islands earthquake swarm that stressing rate governs seismicity , 2002, Nature.

[4]  R. Showstack Panel urges measures to minimize effects of future abrupt climate changes , 2001 .

[5]  D. F. McTigue,et al.  Displacements and tilts from dip‐slip faults and magma chambers beneath irregular surface topography , 1988 .

[6]  G. Fornaro,et al.  Coupled magma chamber inflation and sector collapse slip observed with synthetic aperture radar interferometry on Mt. Etna volcano , 2003 .

[7]  J. Bousquet,et al.  Early deformations at a submarine compressive front: the quaternary Catania foredeep south of Mt. Etna, Sicily, Italy , 1990 .

[8]  A. Tibaldi,et al.  Volcano-tectonic activity along structures of the unstable NE flank of Mt. Etna (Italy) and their possible origin , 2002 .

[9]  A. Bonaccorso,et al.  Dike emplacement forerunning the Etna July 2001 eruption modeled through continuous tilt and GPS data , 2002 .

[10]  Riccardo Lanari,et al.  Dynamic deformation of Etna Volcano observed by satellite radar interferometry , 1998 .

[11]  G. Wadge,et al.  An accurate and efficient method for including the effects of topography in three‐dimensional elastic models of ground deformation with applications to radar interferometry , 2000 .

[12]  M. Tesauro,et al.  Actively growing anticlines beneath catania from the distal motion of Mount Etna's Decollement measured by SAR interferometry and GPS , 2000 .

[13]  C. Chiarabba,et al.  Tomographic images and 3D earthquake locations of the seismic swarm preceding the 2001 Mt. Etna eruption: Evidence for a dyke intrusion , 2002 .

[14]  H. Jäger,et al.  Correction to “Lidar backscatter to extinction, mass and area conversions for stratospheric aerosols based on midlatitude balloonborne size distribution measurements” , 2003 .

[15]  G. Puglisi,et al.  Ground deformation patterns on Mount Etna, 1992 to 1994, inferred from GPS data , 2001 .

[16]  Valérie Cayol,et al.  Effects of topography on the interpretation of the deformation field of prominent volcanoes—Application to Etna , 1998 .

[17]  Sonia Calvari,et al.  Multidisciplinary approach yields insight into Mt. Etna eruption , 2001 .

[18]  Y. Okada Surface deformation due to shear and tensile faults in a half-space , 1985 .

[19]  Fuk K. Li,et al.  Synthetic aperture radar interferometry , 2000, Proceedings of the IEEE.

[20]  A. Borgia,et al.  Importance of gravitational spreading in the tectonic and volcanic evolution of Mount Etna , 1992, Nature.

[21]  R. Goldstein,et al.  Mapping small elevation changes over large areas: Differential radar interferometry , 1989 .

[22]  M. Neri,et al.  The boundaries of large-scale collapse on the flanks of Mount Etna, Sicily , 1996, Geological Society, London, Special Publications.