Etna 2001 volcano eruption
On the 10th July 2001, the southern medium-slope of the volcano began to rise, in the following days repeated earthquake tremors accompanied the opening of a fracture and segment progress oriented in the north-south summit area about 1700mt., that day after day deepened and spread even more, specially in the Pian del Lago area where a notable area caved in.
In the night between 17 th and 18 th four eruptive craters opened along the fracture at different beights: one at the foot of the south-east crater (2900mt.), another around 2700mt., one more at 2600mt. and the last at 2100mt. behind the mechanical area of the Sapienza shelter. In the first phase, effusive activity was accompanied by light explosive activity, only from a crater further down the lava valley area was a modest strombolian activity that began to build a small lava waste cone. In the mean time, the lava flow spread from the crater higher up and began to flow towards the Bove Valley , while the lava flow coming from the 2100mt. crater invaded the road that connects Zafferana to Rif . Sapienza, advancing in the direction of Nicolosi.
In the afternoon of 20 th July, in the Pian
del Lago area, where a caved-in area had been
previously noted, another crater opened that
was characterized, during its eruption, by an
intense piroclastic activity, with 2-3
explosions each minute, from which an imposing
convective column with an elevated charge of
material ash dimension that caused notable
disadvantage to the population living on the
slopes of Etna.the prevailing axis of
piroclastic products was that of the east-west,
followed by dominating wind that blew from
occident causing the worst disadvantage to the
towns in the eastern sector s of Etna. In the
following days intense explosive activity from
the Pian del Lago crater built a waste lava
cone. In the part further down the valley was
found an effusive crater that spilt lava along
the ski tracts in direction cable-car arrival
station. In the mean while, the lava flow from
the crater at 2100mt. stopped dividing into
secondary lava flow on the flat area about
1000mt. and about four kilometres from the
centre of Nicolosi. The eruptive phenomenon
continued until the first week of August, then
stopped.
This eruption was unusual for that which is
the eruptive style of Etna, usually the
explosive activity is dependant on the
effusive, not on the contrary. From
macroscopic observation and a petrographic
analysis of the waste emitted, one has been
able to ascertain that the magma involved was
more viscose that usual and above all,
internally there was a high quantity of quartz
sandstone an unusual phenomenon for lava
erupted from Mongibello recently, probably the
lava had sood for a significant time along the
most superficial levels of the earth's crust,
inside which a fractioning crystalization
phenomenon that developed and enriched the
gas.
Copyright © Roberto Caudullo, "www.etnavolcano.info"
page last modified on 06 august 2005.



