Since the evening of 17 May 2016, intense Strombolian activity has been underway at the Northeast Crater (NEC) of Etna, with the launch of incandescent bombs beyond the crater rim and fallout of pyroclastic material on the sides of the cone. On the morning of today, May 18, this activity was also accompanied by emissions of volcanic ash with a plume directed towards east-southeast, which was dispersed in the atmosphere (see photo above left, taken at dawn from Tremestieri Etneo ). Weak flares were also observed at the November 25, 2015 vent on the upper eastern flank of the New Southeast Crater (NSEC). The amplitude of the volcanic tremor remained high, maintaining the values reached in the evening of the previous day. In the late morning, a clinometer placed at Punta Lucia, at almost 3000 m of altitude and about 1 km NW of the NEC, recorded a rapid inflation (swelling) of the summit area.
Shortly after 12:50 (local time) on 18 May 2016, the INGV-OE visual and thermal surveillance systems recorded the start of eruptive activity at the Voragine (VOR), which in a few minutes took on the character of pulsating lava fountain. At the same time the Strombolian activity of the NEC decreased, passing to dark ash emission, to then cease. The bottom left image shows a frame captured by the thermal camera at Bronte (EBT), about 45 minutes after the start of the VOR activity. With the onset of the paroxysmal activity, a sudden increase in the amplitude of the volcanic tremor was recorded, the source of which moved from the NEC towards the VOR. From the Voragine a plume of ash bent by the east-southeast wind rose, reaching a height of 3000-3500 m above the summit of Etna. In the afternoon, an overflow of lava started from the western rim of the Voragine-Bocca Nuova crater depression, feeding a modest lava flow directed towards the west and limited to the summit area.
At the time of publication of this update, the lava fountain activity at the VOR is continuing. The eruptive activity is constantly monitored through visual, thermal, seismic and ground deformation surveillance systems.
ETNA UPDATE, 18 MAY 2016, 13:45 UTC
Since the evening of 17 May 2016, there has been an intense Strombolian activity at Etna's Northeast Crater (NEC), with ejection of incandescent bombs above the crater rim and fall of pyroclastics over the flanks of the cone. This morning, 18 May, this activity was also accmpanied by emission of volcanic ash forming a plume that was blown eastward by the wind and rapidly dispersed in the atmosphere (see photo at top left, taken from Tremestieri Etneo at daybreak). There were also weak glows at the 25 November 2015 vent on the upper east flank of the New Southeast Crater (NSEC). The volcanic tremor amplitude remained elevated at values similar to those reached on the evening before. On the late forenoon, a clinometer installed at Punta Lucia, at nearly 3000 m elevation and about 1 km northwest of the NEC, recorded rapid inflation (swelling) of the summit area.
Shortly after 12:50 local time on 18 May 2016, the visual and thermal surveillance cameras of the INGV-OE recorded the onset of eruptive activity at the Voragine (VOR), which in just a few minutes evolved into a pulsating lava fountain. At the same time, the Strombolian activity at the NEC diminished and passed into emission of dark ash, and finally ended. The image at lower left is a frame captured by the thermal monitoring camera at Bronte (EBT), about 45 minutes after the onset of the activity at the VOR. With the beginning of paroxysmal activity, the volcanic tremor amplitude showed a rapid increase, and its source migrated from a position below the NEC toward the VOR. From the Voragine an ash plume rose to 3000-3500 m above the summit and was blown by the wind to east-southeast. During the afternoon lava started to overflow from the western rim of the Voragine-Bocca Nuova depression, feeding a minor lava flow toward west, and limited to the summit area.
At the time this update is being published, lava fountaining is continuing at the VOR. The eruptive activity is monitored continuously by the systems of video and thermal cameras, seismic stations and ground deformation.