Stress tensor computations in the mount Etna area (Southern Italy) and tectonic implications

Abstract

Fault plane solutions of several tens of local-shear earthquakes recorded in the Mount Etna volcanic area have been inverted for stress tensor parameters by Gephart and Forsyth's [ J. geophys. Res. 89, 9305–9320 (1984)] method. The main findings can be summarized as follows: (i) stress is homogeneous between 10 and 30km of depth beneath western Etna (longitude <15 °E) with a low-dip N-S σ 1 reconductible to the compressive tectonics of western Sicily and, more in general, to the Africa-Europe slow convergence; some stress heterogeneity is detected at shallower depths in the same sector; (ii) the stress style changes across the 15 °E meridian and becomes more complex beneath eastern Etna, where no uniform stress model is able to explain the available fault plane solutions. In agreement with other geophysical and geological information available from the literature, the results of the present investigation can be explained by assuming that Western Etna belongs to the compressive domain of western Sicily, whereas Eastern Etna is transitional towards the Calabrian Arc tensional domain.