Intrusive Seismic Swarms as Possible Precursors of Destructive Earthquakes on Mt. Etna’s Eastern Flank

Table 2

Intrusive seismic swarm parameters. The duration represents the time interval in which there is contemporaneity between seismicity and ground deformation ([30] and references therein; [50, 63]). The seismic moment was obtained by using (1) and (2) relationships. The 2018 values comprise an estimate of for the 1425 events with not included in the Bonaccorso and Giampiccolo [52] calculus. The last row reports data of the first phase of the October 1984 seismic swarm (16th at 14:00-18th at 12:00).

Eruptive episode	Type	Duration (hours)	Seismic events (°)	Seismic events (events/hour)	(Nm)
1991-93	Lateral	17.0	250	14.70
2001	Eccentric	113.0	2694	23.84
2002	Lateral	19.5	294	15.08
2008	Lateral	6.4	230	35.94
2018	Lateral	31.5	1560	49.52
1984	No eruption	43.0	813	18.91