Report on Stromboli (Italy) — 31 December-6 January 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 December-6 January 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Stromboli (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 31 December-6 January 2003. Smithsonian Institution and US Geological Survey.
38.789°N, 15.213°E; summit elev. 924 m
All times are local (unless otherwise noted)
INGV-CT reported that an effusive eruption began at Stromboli's summit at the base of the NE crater (Crater 1) on 28 December and ended the following day. A survey performed on 29 December, with a thermal camera on a Civil Protection helicopter, revealed that three lava flows had spread in the eastern Sciara del Fuoco (a horseshoe-shaped scarp). The lava flows reached the sea within 30 minutes, and spanned a width of 300 m along the coast.
On 30 December at 1315 and 1322 two landslides suddenly formed along the Sciara del Fuoco. As they traveled down the volcano's flank they produced wet, fine ashfall (less than 0.1 mm in size) on the island's SE side. The first landslide had a volume of about 600,000 m3, the second about 5,000,000 m3, and they both reached the sea. Upon contact with the sea the landslides produced two tsunamis with waves that were several meters high. The tsunamis injured few people, and damaged buildings and boats in the villages of Stromboli and Ginostra. Large waves were reported as far away as the town of Milazzo, on Sicily's N coast, 60 km S of Stromboli.
INGV-CT noted that no explosive activity occurred after the start of the 28 December effusive eruption at Stromboli. In addition, no earthquakes were recorded by their seismic network except for two that were associated with the landslides. On 1 January, a thin lava flow was expanding along the Sciara del Fuoco. As of 6 January effusive activity was ongoing at Stromboli. Lava was being emitted from two vents located at 500 m and 300 m elevation in the middle of the Sciara del Fuoco. The two narrow lava flows merged together before reaching the sea. Occasional small landslides occurred from the unstable walls of the Sciara del Fuoco, covering the lava flows with thin talus. News about the eruption at Stromboli, thermal images of the 28 December flow, and photos and video of the collapse event are available on the INGV-CT website.
Geologic Background. Spectacular incandescent nighttime explosions at this volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small, 924-m-high island is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The Neostromboli eruptive period from about 13,000 to 5000 years ago was followed by formation of the modern Stromboli edifice. The active summit vents are located at the head of the Sciara del Fuoco, a prominent horseshoe-shaped scarp formed about 5000 years ago as a result of the most recent of a series of slope failures that extend to below sea level. The modern volcano has been constructed within this scarp, which funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild strombolian explosions, sometimes accompanied by lava flows, have been recorded for more than a millennium.