Busy week at the Italian volcanoes
The volcanoes of Italy must have known that Dr. Boris Behncke would be in the Q&A; spotlight here at Eruptions because three have shown signs of new activity over the last week. Here is a quick summary based on information from Dr. Behncke and Sonia Calvari of IGVN.
Etna erupting in 1989. Image by Dr. Boris Behncke.
On November 6, Etna in Italy appears to have entered a new phase of activity. The volcano had not produced any explosive events since July 4, 2009, but since 11/6, Etna has experienced a series of deep-seated explosive events – some of which suggest there is a lava lake just below the surface in the SE Crater – described as “a new glowing pit opened on the lower east flank of the Southeast Crater at Etna’s summit, without ejecting any solid material so far by Dr. Behncke. The full update from the IGVN for Etna:
The previous Etna’s effusive eruption, started on 13 May 2008,
finished on 4 July 2009. No explosive activity has been observed at
the summit craters for a few months. On 6 November 2009 deep explosive
activity resumed at the SE Crater. The Istituto Nazionale di Geofisica
e Vulcanologia monitoring web cameras detected pulsating red glowing
from the eastern base of the SE Crater, produced from a vent within
the depression that cuts its eastern flank. Explosive activity is
quite deep and visible as red glows only at night, and no ejecta have
been found on the snow that covers the summit of the volcano. This
activity is still going on as on today, 10 November 2009.
In related news, a recent health study suggests that living near Etna increases people’s chances of thyroid cancer, with rates twice as high near the volcano on Sicily compared to the rest of the island. The study indicates that the cause might be increased levels of radioactive elements such as 222Rn in drinking water near Etna.
Not to feel left out, Stromboli produced an explosion and lava flow on November 8. The lava flow was relatively small (60 m) and confined to the floor of the summit crater. The full news from IGVN:
Stromboli volcano on 8 November produced a major explosion from the
vents in the central crater zone, fragmenting and blowing out part of
the eastern flank of the cinder cone. The explosion produced an
eruptive column more than 350 m high that was drifted SE by the wind.
The explosion was soon followed by a lava flow erupted from the
widened central vent. The lava flow spread within the crater
depression for a few minutes, and reached the maximum estimated lenght
of ~60 m. Lava flow within the crater depression formed also between
22 and 25 April, on 3 May, and on 30 August 2009. After the 8 November
explosion, the explosive activity returned to the background levels.
Finally, Dr. Behncke mentioned that since late September of this year, Vulcano has experienced a gradual increase in seismic activity and fumarole temperatures (italian). However, it seems to have stabilized for the moment.