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Summit eruption at Mount Etna
Istituto Nazionale di Geofisica e Vulcanologia – Sezione di Catania
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From: Sonia Calvari (calvari@xxxxxxxxxx)
(All times are in GMT)
A new summit eruption occurred at Etna volcano on 29 March 2007 at 5:30
GMT. An increase in volcanic tremor was accompanied by fire fountaining
and an ash cloud that rapidly drifted NE. Poor weather conditions
prevented observation, even through the monitoring webcams. However,
satellite images allowed us to record the movement of the eruptive cloud
and its evolution (Coltelli M., Prestifilippo M., Scollo S. & Spata,
Osservazione da satellite della emissione di cenere, INGV-CT Report in
Italian). The episode lasted about 1 hour, and was accompanied by the
re-opening of three eruptive fissures on the summit of Etna, and by lava
flow emission. Two lava flows took place from the 3050 m and 3180 m vent
located respectively on the SE flank of Bocca Nuova and on the saddle
between Bocca Nuova and South-East Crater (SEC), in the same location of
the October-November 2006 events. The two flows merged down slope and
travelled less than 1 km S, halting at the rim of Cratere del Piano, at
about 2900 m a.s.l. (Giammanco S., Rapporto settimanale sull’attività
eruttiva dell’Etna, 26 Marzo - 1 Aprile 2007, INGV-CT Report in
Italian). The third fissure opened at the E base of SEC, and the lava
flow spread within the upper Valle del Bove. The survey carried out in
the early afternoon showed that the flows were already stopped and no
longer fed. Ash and lapilli fallout occurred on a narrow belt comprised
between SEC, Rifugio Citelli and Giardini Naxos, on the NE flank of the
volcano (Andronico D. & Cristaldi A., L’evento parossistico del 29 marzo
2007 - Caratteristiche dei prodotti e dispersione del deposito, INGV-CT
Report in Italian). The composition of the pyroclastics erupted during
the explosive phase (Corsaro R.A. & Miraglia L., Attività esplosiva del
29 marzo al CSE - analisi dei vetri, INGV-CT Report in Italian) shows a
primitive composition, as revealed by the CaO/Al2O3 ratio, much higher
than the products erupted between 1995 and 2006, and suggests that a new
input of magma fed this activity. After this episode eruptive activity
stopped, but volcanic tremor showed since then daily phases of increase
and decrease lasting a few hours each.
All INGV-CT reports cited here can be downloaded from the INGV-CT web
page dedicated to updates on the eruptive activity of Mount Etna:
_http://www.ct.ingv.it/Default.asp?Pagina=./Etna2007/Report.asp_.
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Dr. Sonia Calvari
Istituto Nazionale di Geofisica e Vulcanologia
Sezione di Catania
Piazza Roma 2
95123 Catania (Italy)
Tel. +39 095 7165800 direct: +39 095 7165862
Fax: +39 095 435801 url: www.ct.ingv.it
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