HR: 16:15h
AN: V14B-02    [Abstracts]
TI: Correlation of Seismic, Gravimetric And Geochemical Data During The 2002-2003 Mt. Etna Eruption
AU: Saccorotti, G
EM: gilberto@ov.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Napoli, Via Diocleziano 328, Napoli, 80124 Italy
AU: Zuccarello, L
EM: zuccarello@ct.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Catania, Piazza Roma, 2, Catania, 95123 Italy
AU: Burton, M R
EM: burton@ct.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Catania, Piazza Roma, 2, Catania, 95123 Italy
AU: Carbone, D
EM: carbone@ct.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Catania, Piazza Roma, 2, Catania, 95123 Italy
AU: * La Rocca, M
EM: mlarocca@ov.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Napoli, Via Diocleziano 328, Napoli, 80124 Italy
AU: Del Pezzo, E
EM: delpezzo@ov.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Napoli, Via Diocleziano 328, Napoli, 80124 Italy
AU: Patane', D
EM: patane@ct.ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - Sez. Catania, Piazza Roma, 2, Catania, 95123 Italy
AB: One of the most powerful and voluminous eruptions of Etna's recent history began on late October, 2002. During the first 16 days of eruption, the activity consisted of sustained ash emissions from a crater located at 2750 m elevation on the S flank of the volcano, accompained by lava outpouring from vents located on both the N and S sectors. Eruptive activity suddenly stopped at around 12 GMT on November 12, 2002. During the following 12 hours, the activity at the 2750-m vent evolved to energetic, pulsating Strombolian explosions and strong ash emissions. During this transition, contemporaneous seismic, gravimetric and geochemical measurements provide unprecedented observations of oscillatory phenomena characterising the eruptive dynamics at different time scale. The entire, 12-hour long transition period is associated to a saw-tooth variation of the energy of 1-2 Hz volcanic tremor, to which are superimposed large-amplitude, 24-minute-period oscillations. Both these changes are markedly anti-correlated with the signal recorded by a gravimetric station located about 4 km from the active vent. Noticeably, such anticorrelation is not observed either before or after the 12-hour-long transition period. Location of tremor activity is retrieved through inversion of seismic amplitudes observed at a 6-element broad-band network, and shows a complicate migration of the source occurring at time scale of a few hours. The dynamics of the transition activity is furtherly parameterised through data from a Fourier Transform Infrared spectrometer (FTIR) that recorded the intensity of infrared radiation and the SO2/HCl ratios of emitted gas. Intensity depicts a pulsating behaviour occurring at cycles of about 28 minutes, which are significantly correlated with tremor cycles, lagging, by $\sim$5 minutes. Moreover, intensity and SO2/HCl ratios are almost perfectly anti-correlated throughout the whole transition period. These data offer unprecedented insights into the complex mechanisms governing the eruptive dynamics at Etna Volcano.
DE: 8414 Eruption mechanisms
DE: 8419 Eruption monitoring (7280)
DE: 8434 Magma migration
DE: 8494 Instruments and techniques
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting