Sezione di Catania - Osservatorio Etneo reported that during the late evening of 1 August a vast accumulation of incandescent material appeared at the base of Stromboli's N1 vent, the northernmost active vent within the crater terrace at about 750 m elevation. Within a few minutes, the material collapsed and slid downslope, creating two small lobes of lava. The more easterly flow descended the N slope of the Sciara del Fuoco, generating small landslides from the loose material on the slope, and marking the first lava effusion event outside of the crater since a small emission during 11-12 December 2010. The lava accumulated on a flat area near hornitos that were formed during 2002-2003, before continuing further down a steep slope. On 2 August the lava had descended to 500 m elevation and advanced very slowly. During the afternoon effusion appeared to have diminished.

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)