Report on Stromboli (Italy) — 5 February-11 February 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 February-11 February 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Stromboli (Italy). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 5 February-11 February 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 the effusive eruption that began at Stromboli on 28 December 2002, continued through 6 February 2003. Emission of lava occurred from a main vent located at 500 m elevation in the middle of the Sciara de Fuocco (a horseshoe-shaped scarp), within the scar left by the 30 December 2002 landslide. Another vent, located at 600 m elevation at the NE base of Crater 1, was active several times during the eruption. Slow, short lava flows were emitted from this vent for periods lasting a few hours to a few days. During peaks in effusion rate, aa lava flows reached the sea, causing phreatic explosions at the lava-flow front.
During a thermal survey from a helicopter on 12 January, arcuate cracks were seen around the S base of the volcano's summit craters. Other fractures, oriented NE-SW, cut through the craters. Collapse of the crater's bottom during early January significantly changed the morphology of the upper part of the volcano. Previously there had been three individual craters, but scientists saw that Crater 1 (NE) and 3 (SW) had joined together to form one elongate depression. Crater 2 (the middle crater) no longer existed. INGV-CT noted that no explosive activity had occurred at the summit craters since the start of the activity within the Sciara del Fuocco. News about the eruption (in Italian), thermal images, photos, and videos of the 30 December 2002 collapse event can be downloaded from 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.