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Activity of the Sicilian volcanoes during October 2010

ETNA

During the month of October 2010, Etna has continued to show signs of unrest. There have been several ash emissions caused by collapse and/or explosions within the active western pit (BN-1) of the Bocca Nuova, the westernmost of the four summit craters of Etna; many of these events were not visible due to inclement weather conditions. Thermal images recorded by the Montagnola monitoring camera when there was good visibility revealed no hot material in the emissions, and no ash falls were observed in populated areas. The two most significant explosive events occurred on 7 and 22 October, and produced minor quantities of ash. Analysis of the ash emitted on 7 October revealed very minor quantities of fresh magmatic material – sideromelane (2%) and tachylite (7%) along with old, lithic material and crystals.

A brief sequence of explosions was again recorded during the early morning of 1 November; probably the source was once more the BN-1.

Throughout the month, deep-seated explosions within the open inner pit on the floor of the Northeast Crater have continued, producing loud booms and prolonged rumbling and hissing sounds, which were well audible during visits to the summit made by INGV-Catania staff and the Etnean mountain guides. Field observations revealed that no new eruptive products have been emplaced, neither outside nor within the visible portion of the Northeast Crater. There were fluctuations in the amplitude of the seismic signals produced by this activity, sometimes increasing significantly and at other times vanishing nearly completely.

Vigorous emission of dense gas plumes continued from the collapse pit on the lower eastern flank of the Southeast Crater cone. During windstill weather, the gas plume rose several hundred meters vertically before being driven downwind at higher altitude, forming a trail tens of kilometers long. During a visit by INGV-Catania staff on 8 October, most gas was observe to issue from an open vent located at the base of the western rim of the collapse pit, making a loud hissing noise, at times accompanied by deep rumbling indicative of explosive activity at depth within the conduit. Profuse steaming also occurred from an extensive fumarole field on the upper eastern flank of the Southeast Crater cone.

 

STROMBOLI

Stromboli volcano is in a state of persistent eruptive activity, normally with explosions of medium to low intensity occurring from a number of vents located within the summit crater. During the month of October 2010, the activity showed the typical fluctuations characterizing the activity of Stromboli.

Between 17 and 24 October, Stromboli went through a period of significantly increased activity, with more or less continuous spattering first from a vent on the northern rim of the crater terrace, and then from a hornito in its southwestern portion. From this latter, a small lava flow was emitted, which travelled for a few tens of meters northeastward to spill into a depression in the eastern portion of the crater terrace. Lava effusion lasted from the night of 18-19 October until the evening of the 23rd.

 

VULCANO

Vulcano volcano is currently in a state of quiescence. During the month of October 2010, no anomalies were observed in the geochemical parameters of the peripheral areas (soils in the Vulcano Porto areas and thermal aquifers).