. . . the Société de Volcanologie Genève (SVG) visited Stromboli in early April and observed continued lava production. On 3 April, two vents were active in the summit terrace. Strombolian activity at the main vent ejected tephra to 100-150 m height in explosions that occurred every 20-25 minutes. Explosions at 30-35-minute intervals from the second vent ejected only old material. An effusive vent in the upper NNE part of the Sciara del Fuoco (below and N of the main vent) quietly emitted two small lava flows. The main flow, ~1.5 m wide, moved N at ~0.5 m/s; its front was about halfway down the Sciara del Fuoco. The other flow was only 0.5 m wide and was moving more slowly, to the NNE. Activity the next day was similar, but the smaller lava flow had stopped advancing. On 5 April, Strombolian activity had declined; explosions were less frequent and tephra did not rise as far. One lava flow, ~2 m wide, was active, moving NNE at 1-1.5 m/s.

Geological Summary. Spectacular incandescent nighttime explosions at Stromboli have long attracted visitors to the "Lighthouse of the Mediterranean" in the NE Aeolian Islands. This volcano has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout much of historical time. The small 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 took place between about 13,000 and 5,000 years ago. The active summit vents are located at the head of the Sciara del Fuoco, a prominent scarp that formed about 5,000 years ago due to a series of slope failures which extends 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: P. Vetsch, SVG, Switzerland.