Etna update, 12 January 2011

Strombolian explosion from the active pit crater on the east flank of the Southeast Crater cone on the evening of 12 January 2011 as seen from Piano del Vescovo, at 1375 m elevation on the southeast flank of Etna. Photo taken by Boris Behncke, INGV-Catania

Starting on the late evening (about 21.00 GMT) of 11 January 2011, a slight increase in the volcanic tremor amplitude has been recorded by the INGV-CT seismic network, which reached a peak at 07:00 on 12 January. During the early morning of this day, the source of the tremor was observed to shift from its previous location to the north of the Northeast Crater toward the Southeast Crater. These variations have been accompanied by the resumption of weak eruptive activity within the pit crater located on the eastern flank of the Southeast Crater cone, as observed already during the day of 11 January, and which gradually increased in intensity during the early morning of today. As of 08:45 GMT this morning, the activity continues to be rather weak, without any emission of volcanic ash, whereas dense emission of gas and vapor is observed at the other summit craters of Etna.

On the evening of 12 January, Strombolian activity continued from the active vent within the pit crater; during the afternoon and evening the volcanic tremor amplitude had continued to increase. Shortly after 21:00, lava that had accumulated within the pit crater started to overflow on its low eastern rim, feeding a lava flow that advanced toward the western wall of the Valle del Bove. It is possible that the ongoing activity is producing volcanic ash.

Further details on the ongoing activity will be provided here during the next few hours.

Lava overflow from the eastern rim of the erupting pit crater (seen in Strombolian activity at left), photographed from Trecastagni at 22:05 h on 12 January 2011. Photo taken by Boris Behncke, INGV-Catania