INGV reported that starting at 1510 on 4 December lava overflowed Stromboli’s Area N (North Crater area) in conjunction with intense explosive activity. A strong explosion occurred at Area C-S (South-Central Crater area) at 1516, and at 1528 small collapses began shedding material onto the upper parts of the Sciara del Fuoco. At 1531 lava overflows and explosive activity likely collapsed part of a crater rim in Area N, resulting in pyroclastic flows that descended the Sciara del Fuoco. At 1619 a large pyroclastic flow descended the Sciara del Fuoco for several minutes and generated abundant ash clouds that temporarily blocked the view of the summit area. The pyroclastic flow went some distance over the water and caused a small tsunami. A lava flow was visible on the Sciara del Fuoco at 1640, and by about 1700 it had reached the coast. The lava flow originated from a fissure located just downslope of the N2 vent in the Area N. Abundant amounts of reddish-colored tephra fell in Ginostra, 1.5 km SW of summit. The Dipartimento della Protezione Civile raised the Alert Level to Orange (the second highest level on a four-color scale). Explosive activity continued at Area N.

Lava effused from the vent at variable rates during 5-6 December, with higher rates corresponding to more intense explosive activity. Beginning at about 0830 on 5 December most explosions occurred at N2, with coarse material ejected a few tens of meters above the vent. Boulders rolled down the Sciara del Fuoco and caused diffuse ash plumes that quickly dispersed. Explosions at the summit were generally infrequent.

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.

Source: Sezione di Catania - Osservatorio Etneo (INGV)