Report on Stromboli (Italy) — January 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 1 (January 1993)
Managing Editor: Lindsay McClelland.
Stromboli (Italy) Short series of violent explosions ejects tephra column
Please cite this report as:
Global Volcanism Program, 1993. Report on Stromboli (Italy). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 18:1. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199301-211040.
38.789°N, 15.213°E; summit elev. 924 m
All times are local (unless otherwise noted)
A short series of violent explosions occurred from the summit craters on 10 February at 1610 GMT, ejecting a large tephra column. Lithic blocks and lava fragments fell to 1 km from the summit, and heavy ashfall occurred at the village of Ginostra, ~2 km SW of the summit. Only weak degassing from the summit craters was visible during the next two days.
A sequence of three explosion earthquakes that occurred within <2 minutes of one another was recorded by the Ginostra station of the Aeolian Island Seismic Network, operated by the IIV. The last earthquake was followed by high-amplitude tremor that lasted for 8 minutes, then gradually declined. No other anomalous seismic activity was recorded during the succeeding hours, although spectral amplitude of tremor was remarkably low. No seismicity associated with the explosive activity was detected by any other stations in the IIV network. Tilt data from a shallow borehole station on the lower N flank (at Punta Labronzo) did not show any deformation suggesting significant magma storage in the volcanic edifice.
Geologists noted that the activity appears to be comparable to similar episodes in 1988 and 1989, thought to be caused by shallow gas accumulation building pressure in a feeder pipe.
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: S. Falsaperla and L. Velardita, IIV.