Seismic and volcanic activity during 2014 in the region involved by TOMO-ETNA seismic active experiment

Graziella Barberi Graziella Barberi,Valentina Bruno Valentina Bruno,Elisabetta Giampiccolo Elisabetta Giampiccolo,Domenico Patanè Domenico Patanè,Luciano Scarfì Luciano Scarfì,Simona Sicali Simona Sicali,Alejandro Díaz-Moreno Alejandro Díaz-Moreno,Carla Musumeci Carla Musumeci,Luciano Zuccarello Luciano Zuccarello,Tiziana Tuvè Tiziana Tuvè,Giuseppina Tusa Giuseppina Tusa,Jesús M Ibáñez Jesús M Ibáñez,Ornella Cocina Ornella Cocina

doi:10.4401/ag-7082

Abstract

This paper presents an overview of the seismic and volcanic activity occurred during 2014 in the region involved by the TOMO-ETNA seismic active experiment (Mt. Etna, Aeolian Islands and Peloritani-Messina Strait areas). To better characterize the seismicity over the year, three-dimensional hypocenter locations and focal mechanism solutions of a dataset of 678 selected small-to-moderate magnitude earthquakes (0.5 ≤ ML ≤ 4.3) were analyzed. In the framework of the TOMO-ETNA experiment, a temporary seismic network was installed on-land from June to November 2014, both to acquire seismic signals produced by shots and to record the local seismicity. Data collected by the temporary network were used to integrate those deriving from the permanent seismic network operated by the Istituto Nazionale di Geofisica e Vulcanologia (INGV)-Osservatorio Etneo (Etna Observatory), thus obtaining a numerically more robust dataset. In agreement with previous analysis and studies, the distribution of the hypocentral locations is well representative of the seismicity that typically characterizes this area. The selected well-constrained 42 fault plane solutions evidence two domains characterized by different motions and style of deformation. In particular, an extensional domain in the northeastern Sicily and a strike-slip regime in the northernmost part of the studied region have been observed.

Highlights

Sicily and Calabria (Figure 1a) lie at the boundary between the converging African and Eurasian plates, in a sector of the Mediterranean that is among the most seismically active regions and that has been affected by some earthquakes among the strongest occurred in Italian seismic history
Much still remains unclear about the relationship between seismicity and recognized faults, and between seismicity and volcanism, as well, especially when we look at a geodynamic context larger than the single volcano
Several RMS amplitude features were observed during the study period: (i) high values of RMS tremor amplitude were recorded between January-March 2014, related to the New Southeast Crater (NSEC) eruptive activity; (ii) in late March the amplitude of the volcanic tremor has been decreasing until middle June, when the energy of seismic radiation increased abruptly, and the seismic tremor amplitude achieved high levels (Figure 6b); this particular RMS stage followed the entire eruptive fissure activity occurred on the eastern flank of Northeast Crater (NEC) (Figure 6b); (iii) high values of the tremor amplitude, associated with a powerful lava fountain, were recorded on December 28, 2014

Summary

Introduction

And Calabria (Figure 1a) lie at the boundary between the converging African and Eurasian plates, in a sector of the Mediterranean that is among the most seismically active regions and that has been affected by some earthquakes among the strongest occurred in Italian seismic history (up to intensity X-XI; Figure 1b). In the period SeptemberDecember a new generalized phase of areal dilatation affected the entire volcanic edifice, clearly evidenced at all GPS stations This variation preceded the renewal of the Strombolian activity started on October 7 at the NSEC and the intense paroxysm (lava fountain) occurred on December 28. Several RMS amplitude features were observed during the study period: (i) high values of RMS tremor amplitude were recorded between January-March 2014, related to the NSEC eruptive activity; (ii) in late March the amplitude of the volcanic tremor has been decreasing until middle June, when the energy of seismic radiation increased abruptly, and the seismic tremor amplitude achieved high levels (Figure 6b); this particular RMS stage followed the entire eruptive fissure activity occurred on the eastern flank of NEC (Figure 6b); (iii) high values of the tremor amplitude, associated with a powerful lava fountain, were recorded on December 28, 2014. Earthquakes depth, related to the above stated events, mainly ranges between 10 and 15 km

Aeolian Islands and PeloritaniMessina Strait area

Seismic signals associated with volcanic activity at Stromboli volcano