DESCRIPTION OF THE SITES SUGGESTED FOR A VOLCANOLOGICAL VISIT TO STROMBOLI
dépliant published by Dipartimento della Protezione Civile
and Gruppo Nazionale per la Vulcanologia, Italy
Editorial Project: G. Pasquaré
Text and figures L. Benciolini , G. Pasquaré, F.A. Pasquaré
Drawings M. Pasquaré
Graphic project P. Moneta e D. Noya
web-project: L. Giacomelli , R. Scandone
1 - Walking along the coast, beyond
the pier, you will reach an outcrop of rock that cuts the beach. The outcrop
shows the oldest lava flows of the island which, about 100.000 years ago,
were moving down the slopes of Paleostromboli I, towards the sea, accompanied
by flows of blocks and incandescent scoria.
2 - If you walk 10 m past the C.A.I.
trail sign, at the end of the beach, you will notice, in front of you in
the distance, several lava and scoria flows, emitted about 60.000 years
ago by Paleostromboli II. Their regularly repeated succession indicates
that, at that time, eruptions were continuous and took place with an abundant
3 - By following the trail along
the beach and then turns right, you will reach an old quarry where you
have a chance to observe the evidence of Vancori's initial eruption, which
were extremely explosive. From the bottom to the top you can see lapilli-tuffs,
a lava flow (orange), lapilli-tuffs again and finally pyroclastic flow
products (yellow), genereted by clouds charged with steam and ashes, which,
ejected from the vent, moved down at high speeds, close to the ground.
Looking at the quarry, on your left along the trail, you can observe closely
the lapilli tuffs, noting that tghey derived from a rain of lapilli and
bombs, and that the falling bombs caused the down-sagging of the soft,
underlying layered tuffs.
4 - You can reach this site by
following the C.A.I. trail n. 14, which starts from the coastal road near
the pier. Not far above the last house you can observe, along the trail,
the pyroclastic flows of Vancori volcano. It is possible to see thinner
layers rich in ash, and other layers rich in coarser rocky clasts, which
were fragmented in the upper portion of the eruptive conduit. The presence
of the fragments indicates we were not far away from the ancient crater.
5 - Following Stromboli's lowest
road, after reaching the sign "Città del Sole" turn right towards
the sea and you will reach the Grotta di Eolo. This cave is a lava tunnel,
which formed after the surface of a lava flow cooled and solidified, developing
a continous crust beneath which the still molten interior lava continued
to flow toward the sea. As a result of this processes, a wide cave formed.
To the left of the Grotta di Eolo, beyond the cove, you can observe that a dense, solidified mass of lava has remained beneath the scoriaceous superficial crust. Therefore, it is possible to imagine that, in this area, the flow did not have enough energy to escape towards the sea and create another cave.
6 - Once you have reached the last
bend but one in the trail that leads to the Osservatorio di Labronzo, leave
the trail and climb up 50 m. In front of you you will see a long, deep
and straight-lined valley, extending to the island's summit. This is a
crevice which, 10.000 years ago, cut the flank of Neostromboli volcano.
The fissure emitted fountains of incandescent lava spatter, whose remains
are still visible in the vicinity of the cliff, as accumulations of reddish
7 - You can reach this site by
following the trail that start from the Osservatorio Labronzo and leads
to a green cabin. Climbing up a few meters past the cabin, you will reach
the overlook that lies on the flows erupted by Neostromboli Volcano. Close
to its margin you can see a dark, delta-shaped lava flow, which moved down
along the Sciara in 1985.
8 - Following the trail that leads
to the craters, after reaching the bend located at an altitude of 300 m,
look in the direction of the Sciara and you will see the superimposition
of Neostromboli Volcano on Vancori Volcano. Il is possible to notice an
"angular unconformity" between the lavas of the two volcanoes, due to the
different provenience of the two flows.
9 - A long stretch of the trail
leading to the craters cuts grey ashes containg block and bombs, which
cover the lavas of Neostromboli. The ash deposits resulted from the consolidation
of a "nuée ardente" (glowing cloud) which flowed down from the summit
crater during the exceptional explosive event that took place in 1930.
10 - If you keep moving upward,
you will notice that the lavas of Neostromboli, which had remained indisturbed
for thousands of years, were buried by a heavy rain of black scoria, during
the 1930 eruption.
11 - At an hight of 650 m., along
the same trail, not far above the previous site you can see the flows emitted
during the years immediately following the formation of the Sciara del
Fuoco. Currently, these flows are suspended above the bottom of the present
Sciara. In the background you also see the hanging remain of Neostromboli.
This fact demonstrates that the Sciara's collapses were numerous, and had
the effect of leaving the previously erupted products isolated and suspended
at gradually increasing distances from the bottom of the Sciara.
12 - Shortly before reaching the
summit, in the vicinity of the walls of the first shelter, by observing
the head of the Sciara del Fuoco you will notice the presence of white-yellow
"islands" among the dark ashes erupted by the present cone. They are remains
of Neostromboli, which have been chemically altered by corrosive action
of the fumaroles, still visible in the upper portion of the cone. This
demonstrates how, at Stromboli, every new volcano which had previously
formed and was later deactivated.
13 - Walking upward along the trail,
a few meters beyond the previous site you have the opportunity to observe
the contact between 3 different volcanoes. The flank of the ancient Vancori
Volcano was ripped apart on your right, about 13.000 years ago, by a giant
collapse that originated a semicircular scar. The void generated by the
collapse was filled, later on, with the products erupted by the more recent
Neostromboli Volcano, and these were covered afterwards by ashes and debris
that flow down abundantly from the present cone.
14 - It is possible to observe
the present crater of Stromboli from the Pizzo Sopra la Fossa. The crater
rim is continuously growing, due to the steady emission of ashes an scoria
which, by falling on the crater rim, increase its height. You can distinctly
see inside the crater the three cones ejecting steam and, at intervals,
throwing into the air ashes and incandescent lava spatters.
15 - Following the trail that winds
along the ridge, walk down 50 meters, and you can examine the internal
components of the Pizzo Sopra la Fossa. You will notice that it used to
be a cone (which was for a long time, Stromboli's summit cone), made up
of blocks, ashes and lapilli, expelled during several, quite violent "Strombolian"
eruptions. At present you see only one half of it, owing to the subsequent
collapse of the Sciara del Fuoco.
From the same overlook you can notice, in front of you, the large amphitheatre left by the collapse of Vancori, which was examined at close range from site n. 13.
16 - Looking over the vast extent
of ashes and lapilli of the Rina Grande, pause to observe the rocky rampart
situated on your right. In this place, the black lavas quickly flowing
down from the Pizzo Sopra la Fossa, had emough energy, thanks also to their
particular fluidity, to move upward on the rampart's flank, which represents
the remains of the escarpment left by Vancori's collapse.
17 - If you go twenty or so meters
beyond site n. 16, you will have a chance to take a look at the rim of
Vancori Volcano's collapse. The red lavas represent the recent products
of Vancori, immediately preceding its collapse. The black materials are
ashes and lapilli erupted by the recent and present activity, accumulated
against the escarpment left by the collapse.
18 - Follow the trail that leads
from site n. 16 to the summit of Vancori. Shortly before reaching the summit
you will observe a large accumulation of blocks, scoria and bombs, ejected
during a violent explosive eruption, which probably marked the beginning
of Vancori's collapse.
19 - Walking along the trail that
leads from the Rina Grande to Semaforo San Vincenza, before the last downhill
stretch that goes through the canebrake, go to your left twenty or so meters
and you will reach an accumulation of strongly welded scoria, associated
with lavas. These are products which were emitted by an eruptive fissure
that opened in the north-eastern flank of Neostromboli. The flows erupted
by the fissure moved down and reached the sea, where they are still visible,
East of Ficogrande.
In the background you can see Strombolicchio, an islet composed of lavic breccia. As you can see, numerous dykes cut the inslet. Strobolicchio represents the remaining portion of a volcano much older than Stromboli and nowadays completely dissected.
20 - Along the trail that leads
from Ginostra to Timpone del Fuoco, near the last house it is possible
to examine particular "ropy lavas", which have acquired their ropy shape
due to the fluidity and flow velocity that characterize them. This flow
came from the Timpone del Fuoco, the low cone-shaped relief in front of
you, which was generated by an old parasitic vent of Neostromboli.
21 - Follow the trail that leads
from the Timpone del Fuoco to the Punta dei Corvi. Looking over the Sciara
del Fuoco you will see a sort of massive wall, which represents a dyke,
which is the magmatic filling of a fracture that opened up in the past
in the volcano's flank. Erosion then stripped away the weaker surrounding
rocks, leaving the dyke isolated and higher than the relief around it.
22 - Reaching Ginostra's last houses,
situated in the locality of "Lazzaro", you can take a look at the flank
of the ancient Paleostromboli Volcano, carved by the Vallone Rina. The
valley's incision enables you to observe how the volcano's body is segmented
and interrupted by large fractures, which testify to the volcano's long
and tormented history.
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