Abstract
Over the last few years, three tilt deep stations (27-30 meters) have been set up in the summit area of Mount Etna volcano. The aim of this challenging project is to record the ground deformations of the summit craters activity with high precision. We considered data related to the August 23-26, 2018, Strombolian and effusive activity. In this case, tiltmeters recorded variations in the order of 10−7 radians, not observed at the other stations. These changes suggest a shallow contraction source just south of the Southeast Crater. This result, related to the volcanic tremor source, points to the presence of a gas/magma reservoir feeding the Strombolian activity at 1200 m above sea level.
Highlights
Ground deformation is an important indicator to observe how and why volcanoes change their shape in order to understand and to provide eruption precursors
We report a calculation of the time changes of tremor energy, as the RMS of the seismic signals recorded at the vertical component of ESLN station in the band 0.5–2.5 Hz within 10 min long sliding windows in the period 21-29 August
Before August 23, the tremor source is located below Bocca Nuova (BN) and Voragine craters, in the depth range between 2500 and 3000 m of elevation a.s.l. (Figure 7); successively, corresponding to the increase in volcanic tremor amplitude, the source moved 500-700 meters south-eastwards of the Southeast Crater (SEC) (Figure 7)
Summary
Ground deformation is an important indicator to observe how and why volcanoes change their shape in order to understand and to provide eruption precursors. Mt. Etna’s activity may be grouped into two types: lateral flank eruptions occurring along fracture systems and persistent activity, comprising phases of degassing alternating with Strombolian activity, which may evolve into lava fountains and effusive events [17, 18]. Etna’s activity may be grouped into two types: lateral flank eruptions occurring along fracture systems and persistent activity, comprising phases of degassing alternating with Strombolian activity, which may evolve into lava fountains and effusive events [17, 18] Monitoring this activity is carried out by means of the several surveillance cameras of the INGV-OE [19] and by field surveys (e.g., [20]). Strombolian activity is generally explained in terms of bubble dynamics, where large (
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