Insight into Mt. Etna (Italy) kinematics during the 2002–2003 eruption as inferred from seismic stress and strain tensors

Abstract

Seismic activity linked to the 2002–03 Mt. Etna eruption was investigated by analyzing the Md > 2.3 earthquakes. The results of 3D relocation were used to compute fault plane solutions and a selected dataset was inverted to determine stress and strain tensors. The analysis revealed a complex kinematic response of the eastern flank dominated by fast stress propagation and reorientation. We hypothesize that a vertical dike intruded the southern flank, generating an extensional regime that triggered a radial intrusion in the northeast sector of the volcano. The combined effects gave rise to a rotation of the stress tensor that controlled the activation of the Pernicana fault system. The volcanic and tectonic interactions produced a second reorientation of the stress tensor, causing a structural response in the southeast lower flank. The overall result of the deformation processes observed during the eruption was an E-W extension on the eastern flank of the volcano.