Report on Stromboli (Italy) — July 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 7 (July 1991)
Managing Editor: Lindsay McClelland
Stromboli (Italy) Continued explosions from two craters
Please cite this report as:
Global Volcanism Program, 1991. Report on Stromboli (Italy). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 16:7. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199107-211040.
38.789°N, 15.213°E; summit elev. 924 m
All times are local (unless otherwise noted)
The number and intensity of explosions has continued to fluctuate in recent months, with the average rate remaining slightly higher since mid-March. During a summit visit on the night of 31 July-1 August, >50 explosions were observed between 2100 and 0600. The strongest ejected incandescent material toward the edge of the summit area. Most of the explosions were from Crater 1, the rest from Crater 3, with only gas emission evident from Crater 2 and from a small cone. On this occasion and during other visits over the past several years, durations of precursory noises appeared linked to explosive vigor, with stronger explosions following noises lasting 3-5 seconds, whereas 1-2-second noises preceded weak explosions [see also 16:08].
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.
Information Contacts: H. Gaudru, SVE, Switzerland; T. De St. Cyr, Fontaines St. Martin, France.