Etna update, 14 June 2011
Ash emissions from the Bocca Nuova, recorded by the visible light monitoring cameras of the INGV-Osservatorio Etneo at the Montagnola (EMOV) and on the Schiena dell'Asino (ESV) between 06:28 and 07:17 (GMT = local time -2) on 14 June 2011
Ash emissions resume at the Bocca Nuova
After nearly 6 months of quiescence, ash emissions resumed at the Bocca Nuova - the westermost of the summit craters of Etna - on the early morning of 14 June 2011. On the previous day, mountain guides had heard loud hissing sounds coming from the interior of the crater, presumably caused by high-pressure gas emission. The first ash emission occurred at 05:45 (GMT = local time -2), and was followed by further emissions (the weaker of these set in parentheses) at 04:54, 05:41, 06:03, 06:19. 06:27, 06:43, 06:51, (07:05), 07:16, (07:21), (07:26), 07:32. 07:37, (07:40), (07:47), (07:58). After 08:00, the formation of dense weather clouds has prevented further visual observation.
This activity generated small ash puffs, which rose no more than 200-250 m above the crater rim, before being pushed eastward by the wind. Movie footage recorded by the thermal monitoring camera at the Montagnola (EMOT) showed the complete absence of hot material in the emissions. The source of this activity appears to lie in the central part of the Bocca Nuova. In the meantime, the usual rhythmic emissions of gas and vapor from the Northeast Crater have continued, and conspicuous fumaroles were active on the upper east flank of the Southeast Crater cone, whereas the pit crater on the lower eastern flank of the cone showed weak vapor emission from its rims, mostly on its eastern side.
The Bocca Nuova, which was born in the spring of 1968, has previously been the site of periodic ash emissions in the period between 25 August and 22 December 2010, some of which were much stronger than those of today. At that time, the source of the activity lay within the western pit (BN-1) of the Bocca Nuova. The most recent magmatic activity observed at the Bocca Nuova occurred in the summer of 2002, when weak Strombolian activity occurred within its eastern pit (BN-2). A more significant period of eruptive activity, between 1995 and 2001, led to the complete filling of the crater, culminating in a series of lava overflows between 17 October and 5 November 1999. After these overflows, two large pits formed in the eastern and western parts of the crater, which during the following years progressively grew in diameter (mostly due to collapse of their inner walls), to obtain their present-day configuration.