GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 1.1 13 We focused on three earthquakes that occurred in the post-eruption December 2018 phase. The earthquakes were located using the Hypoellipse algorithm (Lahr, 1989) and the 1D crustal velocity model proposed for Etna area by Hirn et al. (1991) and subsequently modified by Patanè et al. (1994). They occurred on February 6th 2019 (23:38 UTC Ml =2.5), on February 9th (06:02 UTC, Ml=2.9) and on February 10th (04:00 UTC, Ml =2.4), and were felt by the local people living near the epicenter area. We have collected the readings of the P and S-phases recorded by the INGV-OE seismic network with those of the SGR station. This integration has allowed improving the main hypocentral location parameters (GAP; RMS, ERH and ERZ) and to better associate these earthquakes with the geometry of the faults known in the literature. In particular, the earthquakes are ascribable to the seismogenic activity of the main faults system recognized in the study area (Fig.3a,b). On the same days, extensometer data showed millimetric variations at both stations. In particular, ET2 cumulated an opening of about 11 mm and ET1 2.5 mm. Fig. 3 - (a) Investigated area; (b) Epicentral map of three earthquakes located in February 2019.