Etna, Sicilia : explosive event at the NEC.

Etna, Sicilia :   explosive event at the NEC.


During the month of January 2016, Etna’s eruptive activity has maintained rather low levels. Early that month, a few weak ash emissions occurred from the 25 November 2015 vent located high on the eastern flank of the New Southeast Crater (NSEC) cone; similar phenomena were repeated during the last week of January and once more on the morning of 6 February. During the same time interval, degassing from the Northeast Crater (NEC) were sometimes accompanied by the emission of minor traces of ash.

A field survey was carried out in Etna’s summit area by INGV-Osservatorio Etneo (INGV-OE) staff on 19 February. During the visit, no ash emissions occurred from the summit craters, but the NEC was the site of intense degassing from its open conduit; due to strong wind it was not possible to hear if there was any acoustic activity coming from the crater, which typically produces loud bangs and rumblings. At the other summit craters, degassing was limited to extensive fumarolic areas along the crater rims. The eruptive products of december 2015, which fill the single huge depression constituted by the Voragine and Bocca Nuova, were covered with snow except in the areas where vapors were emitted from fissures formed by compaction of the deposit.

At 03:22 UTC (=local time -1) on 23 February 2016, the video and thermal cameras of the INGV-OE recorded an explosive event at the NEC, which ejected incandescent pyroclastics to several tens of meters above the crater rim (see image at top left, recorded by the high-definition visual camera at Monte Cagliato, on the east flank of Etna – click on image for larger version) and produced a dark ash plume that was blown northeastward by strong wind. The images at center left (click on image for larger version) were recorded by the high-sensitivity camera on the Montagnola (EMOH, on the upper south flank of Etna) and also show a few lightning flashes in the ash cloud.

The images recorded by the thermal surveillance camera at Monte Cagliato (EMCT, see images at bottom left – click on image for larger version) show a conspicuous anomaly generated by the explosion, which was followed by minor ash emissions that gradually diminished; as of the late morning of 23 February, intermittent and weak ash emissions are continuing from the NEC.

February 24, 2016. Etna, Sicilia :

Source : INGV .

Photos :  Turi Caggegi.

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