Report on Stromboli (Italy) — 24 December-30 December 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 December-30 December 2002
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, 24 December-30 December 2002. Smithsonian Institution and US Geological Survey.
38.789°N, 15.213°E; summit elev. 924 m
All times are local (unless otherwise noted)
According to an INGV-CT report, "At 1830 of 28 December a new effusive eruption started at Stromboli volcano... Strombolian activity at Stromboli was very intense since May 2002, and lava level within the craters was very high on 19 November, when a survey using a thermal camera from [a] helicopter has been carried out. In November, an overflow from the N rim of Crater 2 formed a small lava flow a few tens of meters long, which spread in the upper Sciara del Fuoco. This event has been accompanied by a greater frequency of explosion-quakes associated to the explosions. Between 7 and 10 December explosive activity from the summit craters decreased. On 11 December Strombolian activity increased again as [reflected in the] frequency of the explosions and heights of ejecta, and was particularly intense at Crater 1, the NE crater. On 28 December the height of ejecta reached 200 m above Crater 1, and the shape of explosions suggested magma very close to the crater rim. This activity climaxed at 1830 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 Crater 1. 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, far away from the villages. The lava flows were up to 300 m wide at the shoreline, and very narrow along the steep slope of Sciara del Fuoco. A small increase in the volcanic tremor accompanied the lava flow emission, and the number of seismic events associated to the eruptive activity is still of about five shocks per hour."
"A thermal survey carried out from [a] 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. A map of the lava flows, today's photos of Stromboli and updated reports (in Italian) are visible on the INGV-CT web page."
According to several news articles, volcanic activity at Stromboli on 30 December caused a landslide, which entered the sea and generated a tsunami. The articles stated that in the small village of Ginostra, waves injured six people, and damaged homes and boats. Residents and tourists were evacuated to nearby Sicily.
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.