WARNING:
Access to the summit area is DANGEROUS.
Violent eruptive episodes are occurring frequently at the Southeast
Crater, and heavy showers of tephra (including clasts tens of
centimeters in diameter) may occur up to several kilometers
away. Lava may also arrive rapidly at up to 1.5 km of distance
from the crater. Besides this, weather conditions are often
unstable. Strong wind, snow or rain and clouds are occuring
frequently in the summit area, and one can get easily lost.
Excursions should be made only with the mountain guides who
can be contacted at the cable car (near the Rifugio Sapienza)
on the southern side of Etna, or (during the summer) at the
hotel "Le Betulle" at Piano Provenzana, on the northern
side.
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22
April 2000 update.
The quiet interval at the SE Crater has continued for the sixth consecutive
day after the eruptive episode of 16 April. During two visits to the
summit area by Boris Behncke (Dipartimento di Scienze Geologiche of
the University of Catania) on 19 and 21 April (on the second occasion
Behncke was accompanied by Carmelo Monaco, from the same department,
and Judit Zachar from the University of Szeged, Hungary), no sign
of eruptive activity was observed at the SE Crater and the Sudestino.
Very weak gas emission was seen at the latter during the 21 April
visit, but this did not increase afterwards.
The 21 April visit also revealed that recent lava flows from the SE
Crater (and/or the Sudestino) have extended further to the W on the
plain to the S of the main summit cone (bordered to the S and SW by
the "Piano" caldera rim, which is shown as a broken line
on the map above), and a lava lobe has extended from there to the
SW, about 100 m further W than the westernmost flow lobe shown on
the map above. Another lava flow has descended from the "Piano"
caldera rim towards Monte Frumento Supino and then turned SW at the
base of that cone, following the course of the 1949 and 1964 lavas
for 500-600 m. This and the more westerly flow are the longest SE
Crater flows emplaced in that area since the crater was born. The
emplacement dates are not known, but they are certainly younger than
25 March. The Monte Frumento Supino flow probably predates the 3 April
eruptive episode (it was already there before the 16 April event,
and there was no lava effusion to that area during the eruptive episodes
of 3 and 6 April), so that this flow was likely produced either during
the 29 March or the 1 April eruptive episode. The more westerly flow
may be of the same age or it was emplaced during the 16 April eruptive
episode.
Yet the summit area of Etna is not fully quiet. As has been common
in the past few months, the Bocca Nuova is the site of frequent discrete
gas explosions, which occur from a vent in its E part. Many of these
explosions consist of powerful, extremely short blasts which frequently
generate gas or vapor rings (more commonly, but wrongly, known as
"smoke" rings). During the past week or so, the frequency
of these explosions appears to have increased, and as of 22 April,
the explosions appear to be distinctly louder and, at times, longer.
On this day Behncke conducted fieldwork between the Rifugio Sapienza
area and Nicolosi, roughly between 1000 and 2000 m elevation on the
S flank of the volcano. Loud rumbling sounds were heard frequently
from the Bocca Nuova over the entire area. Some were short detonations,
while others were somewhat prolonged. Such noises were last heard
by Behncke during the October-November 1999 activity at the Bocca
Nuova, and on other occasions when there was intense explosive activity
at that crater or at the neighboring Voragine. This might indicate
that fresh magma is rising towards the surface in one or both of the
main eruptive vents in the Bocca Nuova.
There were few visible phenomena accompanying the noises. At times
the arrival of the explosion sound coincided with the rise of a dense
puff of gas, sometimes transforming into a gas ring. For the whole
day a dense plume of gas was seen rising from the Bocca Nuova, and
this had also been the case during the 21 April summit visit. After
nightfall no incandescence was visible at the Bocca Nuova.
18
April 2000 update.
No fresh eruptions are known to have occurred at the SE Crater since
16 April, but very bad weather on 17 and 18 April has prevented visual
observations for most of the time. Before the SE Crater erupts again,
enjoy the first photos of the 16 April paroxysm now available on a
separate page.
17
April 2000 update.
One day after the 50th and strongest eruptive episode in the series
initiated less than 3 months ago, the SE Crater has remained quiet.
However, more detail about the course of events is becoming available
with eyewitness reports, particularly that of Judit Zachar, a Hungarian
geology student who was at Torre del Filosofo during the initial phase
of the paroxysm. She arrived just in time to see the initiation of
pyroclastic ejections from the main vent of the SE Crater, and remained
at Torre del Filosofo until the activity culminated at 1430 h.
Until then, the paroxysm was rather a beautiful spectacle, with dark
ash fountains and huge jets of bombs rising from the SE Crater main
vent, while near continuous lava fountaining occurred at the Sudestino.
The onset of the culminating phase was sudden, and it seemed as though
the southern flank of the cone was being blasted out. A dark, ash-laden
cloud shot laterally from the base of the cone, right towards the
Torre del Filosofo, and Judit Zachar fled away from the building towards
south. During the following 20 minutes, there were some jets of bombs
and ash rising obliquely from the base of the cone, which itself had
completely vanished behind a dense curtain of ash and larger sized
pyroclastics.
During the 90 minutes prior to the culmination, avalanches of brownish
ash were frequently visible on the flanks of the cone, often raising
dust clouds that veiled the entire cone for minutes. It seems furthermore
that there was some eruptive activity at the vents on the N or NE
side of the cone - until 1430 none was visible from Catania, but Judit
Zachar reported that she saw intermittent jets of lava on the far
side of the cone when observing the activity from Torre del Filosofo.
Video footage on the Italian State television RAI transmitted on the
evening of 16 April had beautiful images of lava fountains at the
Sudestino and powerful pyroclastic fountains at the SE Crater main
vent. Surprisingly, none of the local newspapers had any photographs
of the 16 April paroxysm - some did actually use "recycled"
images of previous paroxysms, others showed screen shots of the Poseidon
live-cam, but none taken during the most impressive phase. Many notes
distributed via the mass media wrongly gave the length of the preceding
repose as 13 days (not 10).
Ash and scoriae fell over a wide sector, covering an area from Zafferana-Acireale
in the SE to Linguaglossa-Fiumefreddo in the NE. Traffic on the Catania-Messina
highway was slowed due to the ash fall, but no serious incidents were
reported.
Photographs taken during the 16 April paroxysm will be posted on this
site during the next few days. Photos were taken by Judit Zachar from
Torre del Filosofo, and later from the Montagnola (see map at top
of this page), by Behncke from Catania, and by other staff of the
Dipartimento di Scienze Geologiche of the University of Catania from
Zafferana on the SE flank of Etna.
16
April 2000 update.
The SE Crater produced a new, very powerful and highly spectacular,
eruptive episode early on the afternoon of Sunday 16 April after an
unusually long repose interval of as much as 10 days. Although a paroxysmal
eruptive episode may have taken place sometime between 8 and 13 April,
this was the first such event to be observed directly since the 6
April paroxysm, and unless evidence of a paroxysm during the interval
of bad weather (8-13 April) is available, this is considered the fiftieth
paroxysm of the series that began on 26 January. Perfect weather conditions
allowed good observation of the event, which was visible from all
over eastern Sicily, attracting the attention of hundreds of thousands
of people who were out for voting (16 April is the day of the election
of the new Mayor of Catania) and/or for the traditional Sunday lunch
out on the slopes of the volcano. It also provided a unique spectacle
to countless tourists who are now on vacation in Sicily, especially
in Catania and Taormina. The following is based on visual observation
made by Boris Behncke (Dipartimento di Scienze Geologiche of Catania
University) from Catania. Additional information was provided by Charles
Rivière from Tremblay-en-France (France).
Precursory activity at the Sudestino, 15-16 April. During
the afternoon of 15 April, Behncke conducted fieldwork in the area
of Nicolosi, on the S flank of Etna, having a clear view of the summit
area from 1450 until about 1900 h. No unusual eruptive activity was
noted at the SE Crater until the end of observation from that area;
vigorous degassing punctuated by the emission of numerous gas rings
(commonly known as "smoke" rings) occurred at the Bocca
Nuova. Gas emission began to increase slightly between 1800 and 1900
at the Sudestino, just before low weather clouds formed, preventing
any further observation for about one hour.
After nightfall, a weak glow could be observed at the Sudestino, indicating
that slow lava extrusion had resumed at this vent. Throughout the
night, lava emission continued intermittently, with periods of more
intense activity alternating with strongly diminished activity. Explosion
sounds could be heard at Nicolosi in the evening. On the morning of
16 April, spattering at the Sudestino led to the growth of a large
hornito. Then, during the forenoon of 16 April, emission of lava and
gas gradually increased at the Sudestino. The hornito collapsed as
a large flood of lava broke out from the vent, and a small plume of
whitish gas appeared at the summit vent of the SE Crater cone at around
1100 h.
By 1200 h, the gas column rising from the Sudestino had become denser,
and at least two lava flows were moving down the flanks of the cone
that had built around this vent during the past five weeks. One of
these flows moved to the E, the other to the SSE, at a distance of
a few hundred meters from the Torre del Filosofo building, which had
been reached by a lava flow on 14 March. As of 1520 h on 16 April,
there seems to be no new lava at the building. For one hour after
1200 h, fuming at the main vent of the SE Crater was irregular, but
there seems to have been no significant eruptive activity there, neither
was there any sign of activity at the vents on the N and NE flanks
of the SE Crater cone.
Activity culminates at the SE Crater main vent. Shortly
before 1300, intermittent Strombolian bursts became visible at the
main vent of the SE Crater. Initially they produced small black plumes
that rose only a few tens of meters above the summit of the cone,
but then the activity gradually increased, and a diffuse dark plume
began to rise a few hundred meters high. At the same time, a pulsating
lava fountain was visible at the Sudestino, and a third lava flow
began to extend from this vent towards SW. For about 30 minutes prior
to 1330, lava fountaining at the main vent of the SE Crater generated
a dilute tephra column. Only rarely did any pyroclastics ejected with
this fountain fall onto the slopes of the cone.
The activity
at the main vent suddenly increased notably at around 1330, when a
dark, dense tephra column shot up from the vent, rising about 1000
m in few seconds. The upper part of the cone rapidly disappeared behind
a plume of brownish dust, caused by the heavy rain of pyroclastics
onto its flanks. Vigorous explosive activity feeding the eruption
column continued for about ten minutes, then decreased, but increased
again at about 1400 h. Small jets of lava rose continuously from the
Sudestino, reaching heights of several tens of meters, and the three
lava flows fed from that vent were vigorously active. Between 1400
and 1430 h, the main vent of the SE Crater experienced several surges
of increased explosive activity, which were somewhat weaker than the
first one, but each time the cone received heavy showers of pyroclastics.
The phase of most intense activity began sometime around 1430 h, when
a very dense tephra column rose from the main vent of the SE Crater,
reaching a height of up to 5 km above the summit. The column broadened
in its upper part, where much vapor condensed to give it a white color,
attaining a classical mushroom shape. For much of its height, however,
the column was dark gray. During this phase, the SE Crater cone became
entirely invisible due to a dense curtain of brownish-gray ash, much
of which was probably generated by the heavy downpour of pyroclastics,
but it is possible that there was also some activity from vents on
the S flank of the cone.
Vigorous tephra emission ended abruptly shortly after 1450 h, and
after this the main vent of the SE Crater only emitted gas. Similarly,
all eruptive activity ceased at the Sudestino, followed by gas emission.
The 16 April eruptive episode was unusually violent and lasted almost
3 hours, considerably longer than the 6 April paroxysm. The intensity
of the activity may be taken as another indicator of a long repose
interval prior to this episode. Morphological changes at the SE Crater
cone appear to be insignificant (there has been some minor vertical
growth), but significant growth occurred at the Sudestino, which has
attained a pointed shape. Tephra from the explosive phase of the episode
was blown SE, and probably affected a sector between Zafferana, Acireale
and Pedara. Satellite imagery (Meteosat;
see images above) show that a dense plume appeared at Etna at 1430
h, the time when the activity reached its most intense phase - no
significant plume had been produced until then. The plume was fed
vigorously until about 1500 h (actually the activity ceased a few
minutes before 1500 h) and was clearly detached from the volcano at
1530 h. It remained visible in Meteosat images until at least 1700,
by which time it had lengthened to more than 300 km in WNW-ESE direction.
14
April 2000 update.
Since the last directly observed eruptive episode at the SE Crater
on 6 April, there has been very probably at least another episode.
However, bad weather has prevailed on many days since 6 April, and
no direct observations of any eruptive activity have been possible.
On 13 April, Giuseppe Scarpinati noted fresh lava flows that had extended
to the E and NE, on which the snow, which had thickly fallen elsewhere
on the upper slopes of the mountain, had melted immediately. A similar
snow-free flow was visible on 13 April on the slope north of Monte
Frumento Supino (see map at top of this page), where many previous
lavas had been emplaced during eruptive episodes since mid-March.
The count of eruptive episodes now stands at fifty (assuming that
one episode has occurred after 6 April). This apparent indiscrepancy
results from the "discovery" of a previously unknown eruptive
episode which took place early on 13 February during very bad weather.
Fortunately there were observers at Torre del Filosofo that night
who noted that the dense weather clouds were illuminated by intense
glow and could see flowing lava at the S base of the SE Crater cone
through gaps in the clouds (information from Patrick Barois).
Several
other web pages covering the recent and ongoing eruptions of the Southeast
Crater are now available; these contain photos and movie clips of
some of the most spectacular moments of that period.
Etna
in 2000 - a list of all paroxysms at the SE Crater since 26 January
and photos (this site)
Extremely
spectacular video clips, taken by British cameraman and film maker
David Bryant on 15 February 2000
At
"Italy's Volcanoes" -
At Stromboli On-line
An
interview with Boris Behncke, made in late February 2000 by a BBC
team
and a video
clip (RealPlayer)
Photos
of the eruptive activity, 15-23 February 2000, by Tom Pfeiffer (University
of Arhus, Denmark)
Photos
of an eruptive episode on 13 February 2000, posted on the web site
of the Association Volcanologique Européenne, Paris, France
Photos
of the 15 February 2000 paroxysm of the SE Crater, by Thorsten Boeckel,
Germany
Photos
by Marco Fulle, 15-20 February 2000, at Stromboli On-line - very high
quality, as usual
Charles
Rivière's Etna home page, with many photos (the most recent
of March 2000), updates, and other, highly interesting items (in French
and English)