Report on Etna (Italy) — November 1978
Scientific Event Alert Network Bulletin, vol. 3, no. 11 (November 1978)
Managing Editor: David Squires.
Etna (Italy) New SE-flank eruption
Please cite this report as:
Global Volcanism Program, 1978. Report on Etna (Italy). In: Squires, D (ed.), Scientific Event Alert Network Bulletin, 3:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197811-211060.
37.748°N, 14.999°E; summit elev. 3295 m
All times are local (unless otherwise noted)
A new SE flank eruption began on 18 November. Initial activity consisted of ejection of ash and wallrock from one of the spatterspatter cone cones formed in the August eruption. Ejection of incandescent ash and larger tephra from this cone started during the morning of 23 November, and was accompanied by minor lava effusion on the crater floor. Lava fountains rose 500 m above the August cone during the afternoon of 25 November and lava began to flow eastward into the Valle del Bove. That night, two new vents opened on the wall of the Valle del Bove at about 2,600 m altitude, extruding flows that traveled 4 km E, to an altitude of 1,500 m. Strong ash emission from the August cone was visible from 40 km away on 26 November.
Two more vents opened in the Valle del Bove on 27 November at 1700 m above sea level, and another vent opened nearby the next day, at 1,800 m altitude. Lava flows from these vents had traveled 4 km into the Valle Calanna, a steep valley extending SE from the E end of the Valle del Bove, by the evening of the 27th. A sixth vent opened that night at 1,650 m altitude, extruding lava that advanced slowly toward the town of Zafferana Etna (population 7,000), a few km S of Milo. The eruption ended during the night of 29-30 November.
Geologic Background. Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism, dating back to 1500 BCE. Historical lava flows of basaltic composition cover much of the surface of this massive volcano, whose edifice is the highest and most voluminous in Italy. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur, sometimes simultaneously. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more summit craters. Flank vents, typically with higher effusion rates, are less frequently active and originate from fissures that open progressively downward from near the summit (usually accompanied by Strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower-flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.
Information Contacts: R. Romano, IIV; UPI; AP.