ETNA UPDATE, 1 MAY 2014, 10:00 GMT

Following the series of strong eruptive episodes of October-December 2013, Etna's New Southeast Crater (NSEC) remained in a state of quiescence until the late evening of 21 January 2014, when a series of Strombolian explosions heralded the onset of lava emission from new vents at the eastern base of the NSEC cone. For the next two months, this rather classical "persistent" summit Strombolian activity accompanied by subterminal lava effusion continued in a virtually continuous manner, though with significant fluctuations. Lava flows extended toward southeast reaching lengths of up to 4.4 km from the effusive vents, and extending beyond the longest lava flows of the 2011-2013 paroxysms; lava lobes also extended toward the northern portion of the Valle del Bove around Monte Simone. The activity stopped rather abruptly in the night between 26 and 27 March; mild Strombolian explosions accompanied by very minor effusive activity from the lower eastern flank of the NSEC cone resumed again on 2 April but ended sometime around 7 April.

No eruptive activity was observed at Etna until the very early morning of 22 April, when sporadic and rather weak Strombolian activity resumed at the NSEC. This activity coninued intermittently over the next few days, always at rather low intensity. Some explosions launched incandescent pyroclastic material out of the crater and onto the upper southern and southeastern flanks of its cone. No lava flow emission was observed, but a few small collapses occurred on the unstable eastern flank of the cone, in particular at 09:33 GMT (=local time -2) on 29 April. On the late evening of 30 April, the frequency and intensity of Strombolian explosions at the NSEC showed a slight increase (see photo at left, recorded by the high-sensitivity camera at the Montagnola, EMOH, at 23:23 GMT on 30 April).

There has also been an increase in the degassing from the Northeast Crater, at times showing slightly elevated temperatures that appear as thermal anomalies in the images of the thermal camera at Monte Cagliato (EMCT).

The volcanic tremor amplitude does not show significant changes, but oscillations known as "banded tremor", linked to hydrothermal activity within the volcanic edifice, has been continuing since the cessation of the eruptive activity of early April.