Seismic swarm below Etna's northwest flank, 5-8 May 2011
Starting on 5 May 2011, the seismic network of the INGV-Catania has recorded a seismic sequence of more than 170 earthquakes (until Sunday, 8 May), which were localized below the northwestern flank of Etna, in an area located about 6 km SE of the village of Maletto, and at a depth of 20-30 km. The main shock, which occurred at 17.12 h (local time = GMT+2) on 6 May, had a magnitude M=4.0, and was widely felt in the Etnean region and as far as the northern part of the province of Siracusa, but no damage was reported.
The largest number of earthquakes, about one hundred, were recorded on 5 May; 26 events had magnitudes superior to 2.0.
The same area had been affected recently (December 2009 and July 2010) by seismic activity with essentially the same characteristics, and is thought to be related to the crustal dynamics of the orogenic chain to the north of Etna.