Seismic activity accompanying the 1974 eruption of Mt. Etna

The 1974 flank eruption of Mount Etna: An archetype for deep dike‐fed eruptions at basaltic volcanoes and a milestone in Etna's recent history

“…In this paper we focus on the January–March 1974 flank eruption of Etna that, as we show thereafter, can be considered as an archetype for DDF‐type flank events. This eruption was unusual in several aspects: it was preceded and accompanied by one of the most intense volcano‐tectonic seismic crisis ever registered on Etna (600 recorded earthquakes, many of them felt, and nine of which with magnitude ≥4 [ Bottari et al , 1975; Guerra et al , 1976]); it was highly explosive and developed in two phases of similar length and pattern, separated by as much as 22 days; and its erupted aphyric magma markedly differed from all previous historical Etnean lavas in being enriched in potassium and other alkalis [ Bottari et al , 1975; Tanguy and Kieffer , 1977; Clocchiatti et al , 1988; this work], 226 Ra [ Condomines et al , 1987, 1995] and both radiogenic strontium and boron isotopes [ Tanguy et al , 1997; Tonarini et al , 2001]. In the past, Mount Etna had occasionally erupted alkali‐enriched magmas during the Holocene (Mount Maletto basalt, 7 ka [ Kamenetsky and Clocchiatti , 1996; Schiano et al , 2001]) and then at 3930 ± 60 years B.P.…”

“…Paradoxically, despite its singularities little attention has been paid to the 1974 flank eruption since early reports and publications in the mid‐1970s [ Guest et al , 1974; Tazieff , 1974; Working Group for the Surveillance of Etna , 1974; Bottari et al , 1975; Tanguy and Kieffer , 1977; Guerra et al , 1976]. Moreover, in these reports contradictory interpretations were proposed for its origin, some authors favoring its shallow derivation [ Guest et al , 1974; Bottari et al , 1975; Guerra et al , 1976] and others its direct feeding from mantle depths [ Tanguy and Kieffer , 1977]. Therefore, for all these reasons we decided to carry out new investigations of this important event, in order to get improved understanding of its genesis and significance for the recent volcano evolution.…”

“…Our results provide an updated evaluation of the solid and volatile budget the 1974 flank eruption and quantitative assessment of the depth and dynamics of ascent of its trachybasaltic magma. Combined with contemporaneous volcanological observations and data for the preeruptive and syneruptive seismicity [ Bottari et al , 1975; Guerra et al , 1976], they allow us to propose a new interpretation of its triggering mechanism. We then examine the significance of the 1974 event with respect to recent changes in Etna's feeding system, by comparing its singular magma geochemistry to that of aphyric products from the 1763 and 2001–2003 DDF‐type eruptions.…”

Seismic activity preceding the 1983 eruption of Mt. Etna

“…Etna has been the subject of several recent studies (e.g., GUERRA et al, 1976;BARBANO et aI., 1979;COSENTINO et al, 1979COSENTINO et al, , 1981SCARPA et al, 1983), and the present state of seismological research at Mr. Etna…”

Tree-ring width reveals the preparation of the 1974 Mt. Etna eruption

“…Etna3437 with up to 150 events per day detected at the Mt. Vetore station (20 events per day at the Catania station; Fig.…”