|
WARNING:
Access to the summit area is VERY
DANGEROUS. Violent eruptive episodes are occurring
every few days 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 on the plain between
Torre del Filosofo, Monte Frumento Supino, and the summit crater
cones. The Torre del Filosofo area, which is familiar to many
excursionists, is presently not a safe place at all. Tourists
are presently not allowed to go beyond 2700 m elevation,
and they should make excursions only with the mountain guides.
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. The mountain guides
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.
|
20 May 2000 update.
The SE Crater erupted with its 56th paroxysm in four months at about
midnight on 20 May, following a buildup in the activity late in the
evening of 19 May. During and after the paroxysm, large amounts of
ash were also erupted from the nearby NE Crater. Tephra falls affected
the E side of the volcano, and as a result of the repeated tephra
falls on many towns and villages in that sector, the Italian government
has declared the state of emergency for Zafferana Etnea, Sant'Alfio,
Milo, Acireale, Giarre, Riposto, Mascali, Santa Venerina, Aci Sant'
Antonio and Aci Catena.
Observations of the event were made by Giuseppe Scarpinati (Italian
correspondent of the Frenche Association Volcanologique Européenne,
"L.A.V.E.") from Acireale, and by British cameraman David
Bryant (back to Etna after almost two months!) and Boris Behncke (Dipartimento
di Scienze Geologiche, University of Catania) from Fornazzo.
Lava effusion from the lower N flank of the SE Crater cone began to
increase notably at around 2230 h on 19 May, and a lava flow extended
about 1.5 km into the Valle del Bove during the following hour, forming
several branches in its most advanced part. Lava spattering began
at the effusive vent at about 2330, while Behncke and Bryant were
driving up on the E flank towards the village of Fornazzo. When they
arrived there at about 2350, a lava fountain was jetting from that
same vent to a height of 50-100 m, and the lava output increased.
The flow into the Valle del Bove advanced with numerous active fronts.
At the same time, the first Strombolian bursts occurred at the summit
vent of the SE Crater, producing very tall jets of lava which rose
at least 250 m high. The glow from this increasing activity illuminated
a dense column of ash which rose from the NE Crater, but no incandescence
was seen at that crater, which had shown similar sympathetic behavior
during the latest three paroxysms of the SE Crater.
The true paroxysmal activity started a few minutes before midnight
when the Strombolian bursts from the summit vent blended into a continuous
fountain, and a continuous rumbling sound became audible. Sometime
later, more vents opened on the N flank of the cone, forming a continuous
curtain of fire between the summit vent and the vent on the lower
N flank. The cone and much of the fountains were soon veiled by a
dense curtain of falling ash, but large bombs from the summit fountain
were seen to rise very high amidst that veil, reaching heights of
up to 800 m above the vent. A low pulsating fountain was occasionally
seen at still another vent high on the S flank of the cone. For about
30 minutes the activity continued vigorously, and the plume of falling
tephra hid most of the fountains and the cone from view; to the S
a near continuous rain of large bombs could be seen which fell to
several hundred m from the base of the cone.
A tall eruption column rose several kilometers into the sky, its white
upper mushroom-shaped portion being beautifully illuminated by the
moon. The plume moved to the E, while the falling tephra was carried
by shear winds in a slightly more southerly direction.
After 1230 the activity became discontinuous, although this was probably
the period of very powerful explosions at the summit vent, which ejected
bombs over a wide area. The summit fountain died out first, followed
by the upper flank vents, but the vent at the N base of the cone remained
active for some time. As the veil of falling ash lifted, all vents
became again visible. A broad lava flow extended from the SE Crater
to the NE, with numerous active fronts that advanced rapidly on the
steep slope separating the Valle del Leone from the Valle del Bove.
The most distant flow fronts were between 1.5 and 2 km from the crater.
The NE Crater continued to emit a dense column of fine ash as the
activity at the SE Crater waned.
Ash and lapilli began to fall at the site where Behncke and Bryant
were observing and filming the activity only when the paroxysm was
almost over. The tephra fall produced a sound like rain as it fell
on the leaves of trees and bushes. During the entire paroxysm an eerie
atmosphere was perceived by those who were there: at the beginning
of the most violent activity, birds were singing in the trees, while
cats and dogs were miowing and barking ceaselessly, and the whole
spectrum of sounds was interrupted every 15 minutes by the church
bells of nearby Fornazzo.
The main tephra fall occurred in a relatively narrow sector between
Fornazzo and the N part of Zafferana, affecting mostly the villages
of Milo and Sant'Alfio. The area between Zafferana and Acireale, which
was stricken repeatedly by tephra falls in recent weeks this time
did not receive much tephra.
The NE Crater continued to emit ash during the day of 20 May, causing
light ash falls in the same sector that had received the tephra of
the paroxysm during the preceding night. The plume was very well visible
as a dark gray streak in Meteosat images, extending at least 200 km
to the ESE. This activity continued as this update was posted (1500
h on 20 May).
On 19 May, the Italian government declared the state of emergency
for ten towns and numerous smaller villages located in the E sector
of Etna. This measure was introduced in order to facilitate financial
and logistical aid for the stricken area, which has received tens
of tephra showers in the past four months. The state of emergency
will remain in vigor until 31 December 2000.
19 May 2000 update.
No significant eruptive activity has occurred at Etna throughout this
day, but at nightfall, a small active lava flow issuing from the N
side of the SE Crater cone has become evident. This flow was also
active early on 19 May, and it seems that very minor effusive activity
at that site is now essentially continuous between paroxysms. This
is very similar to the conditions at the crater in early February,
when paroxysmal eruptive epsiodes occurred very frequently. A new
paroxysm may occur within the next 24 to 48 hours, it will likely
be preceded by an increase in the lava output at the eruptive fissure
on the N side of the SE Crater cone.
18 May 2000 (2030 h) update.
The paroxysmal eruptive episode announced in the previous update (18
May, 0005 h) occurred shortly afterwards at the SE Crater, 49 hours
after its predecessor. For the 55th time in less than 4 months the
paroxysm produced very spectacular lava fountains from several vents
at the summit vent and on the N flank of the SE Crater cone, extensive
lava flows from the N flank vents, and a small volume of lava from
vents on the S flank of the cone. The following is based on observations
made by Giuseppe Scarpinati (Italian correspondent of the Frenche
Association Volcanologique Européenne, "L.A.V.E."),
British cameraman David Bryant (back to Etna after almost two months!),
mountain guides of Piano Provenzana, on the N flank of Etna, and by
Boris Behncke (Dipartimento di Scienze Geologiche, University of Catania).
The activity began with the emission of a small lava flow from the
lower N flank of the SE Crater cone during the late afternoon of 17
May. At about the same time vigorous ash emissions came from the NE
Crater, which continued with some fluctuations for the next few hours,
but without incandescent ejections. At 2245 h, mild lava spattering
began from the effusive vent on the N flank of the SE Crater cone,
and the lava output rate increased notably. The lava formed several
lobes that extended E into the Valle del Leone, reaching a length
of at least 1 km by midnight.
|
Photos
of the 18 May 2000 paroxysm
Photos
were taken by Fabrizio Villa and posted on
the web site of the newspaper "La Sicilia"
|
|
|
|
|
|
Spectacular
photos taken by press photographer Fabrizio Villa (Catania)
during the 18 May 2000 eruptive episode of the SE Crater. Photos
were taken from the E and NE sides of the volcano
|
The first
Strombolian bursts at the summit vent of the SE Crater were seen at
0015 h. Thereafter the activity increased rapidly, and continuous
lava fountaining began at 0035 h, involving at least three major vents
at the summit and the N flank of the SE Crater cone. Smaller vents
were intermittently active along the N flank fissure, and minor eruptive
activity was observed at smaller vents that were briefly active in
other locations on the cone, apparently not along the main fissure
cutting the cone from N to S. The activity reached its climax at about
0045 h, when four large lava fountains jetted more than 500 m high.
Five minutes later, the activity extended to the S flank of the cone,
where minor spattering occurred, and lava was emitted to form a short
flow which apparently extended to the SW.
The paroxysm ended at 0107 h with a series of very powerful, loud
explosions which sprayed bombs over a wide area around the cone. The
entire cone remained incandescent for about 5 minutes after the end
of the activity, with numerous slides of glowing material on its flanks.
At about 0500 h, only a very small active lava flow was observed at
the N base of the cone.
During the paroxysm a dense plume of gas and ash rose from the erupting
crater, which was illuminated by the full moon. The plume moved SE
and began to drop ash and lapilli over towns and villages in an area
between Zafferana, Viagrande, Acicastello and Acireale. This area
had already been affected by similar tephra falls after the paroxysms
of 26 April and 5 May, and on several earlier occasions during the
past four months.
This was the third paroxysmal eruptive episode at the SE Crater in
three days. The repose intervals between these events has thus shortened
notably; during the period from 6 April to 15 May the quiet intervals
had always lasted 9-10 days. The paroxysms themselves continue to
strictly follow the same scheme, with a gradual buildup of the activity
over several hours, and the most vigorous phase of activity lasting
20-30 minutes. This increase in the frequency of the eruptive episodes
coincides with the reactivation of the NE Crater, which showed beautiful
Strombolian activity during the night of 14-15 May. People at Piano
Provenzana succeeded in taking photographs of the erupting NE Crater
and lava emission at the SE Crater, which is one of the very few times
the two craters were seen erupting simultaneously. On 18 May, the
activity of the NE Crater was limited to emissions of dense plumes
containing some ash, but no incandescent ejections were visible as
night fell. The countdown for the next paroxysm at the SE Crater has
begun; this might occur sometime during the next few days, but given
the very irregular intervals between the most recent eruptive episodes
it is impossible to make any more precise "forecasts" unless
the crater reenters a new phase of premonitory activity.
At this point it is necessary to repeat the advice to anybody who
intends to visit Etna to stay away from the summit crater area.
Violent eruptive episodes may occur at the SE Crater at relatively
short intervals. Much of the premonitory activity - which commonly
occurs at the N side of the SE Crater cone - is invisible to visitors
who stay on the S side of the cone, and once the activity extends
to its summit vent, it may very rapidly evolve into the paroxysmal
phase, with a high risk of bombs and large scoriae falling at quite
some distance from the cone, especially on the downwind side. The
risk is even higher in these days as weather condidions continue to
be unstable, and the summit area is veiled in dense cloud for most
of the day. The wisest thing is to go with the guided excursions organized
regularly on both the N and S sides of Etna. They certainly can not
render the thrill of peering into the summit craters (which are anyway
largely filled with the products of the intense activity of the past
five years), but they guarantee a high level of safety.
18 May 2000 (0005 h) update.
Once more, lava is flowing from the N flank of the SE Crater cone,
and this is an almost certain indicator of an impending paroxysmal
eruptive episode at that crater within the next 12 hours or less.
Lava effusion was first observed at about 2240 h by Giuseppe Scarpinati
from Acireale; by midnight the lava flow was well visible from Catania
and had extended at least 1 km down the E flank of Etna into the Valle
del Bove. No other activity was observed at the time of this update.
17 May 2000 update.
After one day of more or less complete confusion it has become clear
that the vigorous eruptive activity on the late evening of 15 May
has occurred from the SE Crater, not, as it seemed, from the NE Crater.
Sebastiano Raciti, who lives in the town of Pedara on the SSE flank
of Etna, observed lava fountaining from the SE Crater which began
shortly before 2315 h and continued until for about 20 minutes, producing
a large plume which moved in the direction of his home town. Lava
was emitted from the N flank of the cone, moving towards the Valle
del Leone (observation by Giuseppe Scarpinati, Acireale). Meanwhile,
activity at the NE Crater seems to have been limited to moderate Strombolian
activity accompanied by strong ash emissions. A weak, fluctuating
glow was observed at that crater on the evening of 16 May by Scarpinati,
but there was also a small area of incandescence on the lower N flank
of the SE Crater cone, possibly caused by very minor lava extrusion
or emission of hot gas from the eruptive vents that erupted the night
before.
The sequence of eruptive spasms on 15 May shows that Etna is capable
of changing its behavior rapidly. The eruptive episode from the SE
Crater that occurred shortly before noon on that day could be perfectly
foreseen, but the next one, twelve hours later, came as a complete
surprise. Based on the behavior of the crater during the preceding
weeks the next paroxysm was expected to occur after 9-10 days of quiet.
It is thus very difficult to express any prognosis concerning the
future development of the activity at Etna's summit. Yet it is likely
that episodic activity will continue at the SE Crater at intervals
of several days, but these intervals may be shorter than during the
past 6 weeks. More precise forecasts can only be made once the activity
shows a clear increasing trend.
|
Photos
of the 26 April 2000 paroxysm:
The view from Sant'Agata li Battiati
These
photos are courtesy of Giovanni Sturiale
|
|
|
|
|
|
|
Eruptive
episode at the SE Crater on the morning of 26 April 2000, photographed
from the town of Sant'Agata li Battiati (to the N of Catania).
These four photos, taken at intervals of about 5 minutes at
the same angle, show the progressive growth of the eruption
column that rises from the crater, eventually reaching a height
of about 5 km above the summit of Etna. Note fallout to the
right of the column in last image. Shortly after this eruptive
episode an airplane encountered the plume while taking off from
the international airport of Catania, and had to return to the
airport. The pilot reported that the plume had not been visible
to him
|
|
Photos
of the 5 May 2000 paroxysm:
The view from Sant'Agata li Battiati
These
photos are courtesy of Giovanni Sturiale
|
 |
 |
 |
|
Eruptive
episode at the SE Crater on the evening of 5 May 2000, seen
from the home of Giovanni Sturiale in Sant'Agata li Battiati;
view is the same as in the 26 April 2000 photos above. The episode
occurred shortly after sunset, but the higher parts of the eruption
column are still illuminated by the setting sun.
|
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 and video clips
(the most recent of the paroxysm of 5 May 2000), updates, and other,
highly interesting items (in French and English)
