PSN-L Email List Message

Subject: Fw: Further eruptions, lava flowage and tsunami at Stromboli.
From: "Erich Kern" efkern@.............
Date: Tue, 31 Dec 2002 17:43:57 -0800

-----Original Message-----
From: Dan Shackelford [mailto:danshack@..............
Sent: Tuesday, December 31, 2002 4:48 PM
To: gvn@............... mayberry@..............
Subject: Further eruptions, lava flowage and tsunami at Stromboli.

Following the strong explosion and lava flow production of 28 December at
Stromboli, the lava flows appeared to cease moving that day. However, by 30
December the lava flowage down the Sciara del Fuoco had resumed, although
at a slower rate than that of the 28th. At 1325 on the 30th there was
another strong explosion with a large amount of ash. A small tsunami also
occurred, likely the result of the collapse of part of the lava fields on
the Sciara del Fuoco (perhaps more than the lava flows collapsed, it is
unclear.). About 6 people were injured by the tsunami. There have been
voluntary evacuations from the island.


31 December 2002, 8.30
Update: The tsunami phenomenon, which yesterday we defined "small" in order
to avoid useless alarms when news were still very confusing and
contradictory, has revealed hour after hour all its severity. The greatest
damages were recorded in Ginostra, but also in the village of Stromboli
many boats were destroyed or taken away by the waves, and many buildings
were damaged. At least 3 tourists are reported injured, and other sources
talk of 6 injured in total. The tsunami has reached also the other Eolian
islands and Milazzo harbour, where 2 tankers suffered difficulties. During
the evening, following the invitation of the Civil Defense, tens of
inhabitants and tourists voluntarily left the island. Moreover, since this
For what concerns the dynamics of the phenomenon producing the tsunami,
there are no evidences of summit eplosions, but only of the collapse, as we
suggested yesterday, of part of the lava field over the steep slope of the
Sciara del Fuoco, that may have detached only by gravitational instability.
This hypothesis is supported by the observation, yesterday afternoon, of a
big scar at about midslope on the Sciara (source: the volcano guides
Antonio Famularo and Nino Zerilli) and by the seismic data recorded by INGV
- Catania, which show the presence of two non-volcanic seismic events, at
13:15 and 13:22 local time respectively.

30 December 2002, 14:55
Update: The village of Stromboli is currently without power supply,
probably because of a fault in the power engine, located close to the
coast. First damages to walls and buildings near the coast are reported,
due to the tsunami wave. Moreover, new ash-rich explosions are reported
near the Sciara, which suggests new interactions between magma and
seawater. A new survey of Civil Defense and INGV is currently in progress.

30 December 2002, 13.45
Update: A new, strong, explosion, observed at about 13:25 local time, has
ejected a great amount of ash that is now falling, mixed with rain, over
the village of Stromboli. The explosion must have caused a collapse of part
of the lava flow deposits (or more) along the Sciara del Fuoco, as a small
tsunami was observed all along the coast near the villages, from Ficogrande
(up to the road) to Scari (up to the helipad). Also in Ginostra boats were
moved by the tsunami in the small harbour. The explosion was apparently not
so loud, and no earthquake was felt by the population.

30. December 2002, 11.00
Update: According to the Stromboli volcano guides, and in particular to
Antonio Famularo, the lava flows resumed their movement after a pause,
although slower than the first day. The flows seem to originate from a
(new? different?) fissure, at about 800 m, below the NE crater. The flows
still reach the sea, producing a smaller amount of vapour with respect to
the beginning of the eruption. The lack of visibility at the top still
prevents observers from evaluating the level of strombolian activity at the
craters during the lava effusion.

28. December 2002
Abbreviated from report by Sonia Calvari, Istituto Nazionale di Geofisica e
Vulcanologia, via VOLCANO listserv: "On 28 December the height of ejecta
reached 200 m above NE Crater, and the shape of explosions suggested magma
very close to the crater rim. This activity climaxed at 18:30 with a strong
explosion that caused ash fallout on the village of Stromboli, accompanied
by the opening of an eruptive fissure trending NE-SW. The fissure opened at
the NE base of NE Crater. A lava flow came out from the base of the
fissure, and formed three lava branches spreading within the Sciara del
Fuoco. Within 30 minutes the flows reached the sea, about 1 km away. The
lava flows were up to 300 m wide at the shore line, but very narrow along
the steep slope of Sciara del Fuoco.

A thermal survey carried out from helicopter on 29 December did not allow
us to see the craters because of poor weather conditions. A thick cloud was
covering the summit of the volcano above 600 m a.s.l. The lava flows below
this elevation were cooling and did not show any movement, suggesting the
end of the effusive phase. Photos are on the INGV-CT web page."

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