The 1974 eruption of mount etna

The 1974 Etna eruption that occurred on the lower, west part of the volcano is rather exceptional as it appeared independent of the central main vent activity. The products of this eruption also differ from those commonly emitted throughout historic times. They are almost aphyric and display an unusual order of crystallization, clinopyroxene being a near liquidus phase instead of plagioclase that is typical in all other recent lavas. The chemical composition is also slightly more basic than that of pyroclastics contemporaneously erupted by the summit Central Crater. These volcanological and petrological features are symptomatic of a separation at depth of the 1974 magma from the central conduit. The eruption itself, however, appears to have been governed by the general structural environment of the volcano. From this stand-point, there is evident interdependence between the various paroxysms of the past five years and it is suggested that the volcanic activity itself has direct relations with the regional tectonics. A model of the superficial structure of Mount Etna is given that best accounts for the observations.