Magma uprising and flank dynamics on Mount Etna volcano, studied using GPS data (1994–1995)

Abstract

[1] Ground deformation occurring on Mount Etna from 1994 to 1995 is analyzed in this paper. This period was characterized by intense volcanic activity at the four summit craters, with frequent strombolian activity, fire fountains, and emplacement of several new lava flows. Four GPS surveys were carried out during this time, two as routinely planned each year and an additional two in 1995 to acquire more data to follow the activity at the NE Crater. The comparisons between GPS surveys are reported in terms of horizontal and vertical displacements of each station and in terms of areal dilatation and principal strain axes. During the period considered in this work, a trend of increasing areal dilatation of the volcano (at a rate of about 5 mstrain/yr) was recognized; it was briefly interrupted by a small contraction (about 2 mstrain), in the autumn of 1995, when volcanic activity at the summit craters began. In detail, the strain distribution of the network is analyzed; it allows the detection of areas showing anomalous behavior, such as the summit zone or the Pernicana fault. Inversions of the ground displacement vectors have been performed by appropriately combining numerical and analytical approaches. Results of the inversions suggest structures defining an eastward and southward sliding of the eastern and southeastern sectors of Mount Etna.

Composite ground deformation pattern forerunning the 2004–2005 Mount Etna eruption

“…[37] In the eastern sector, Mount Etna is characterized by an eastward movement which is an important feature of Mount Etna volcano dynamics, as highlighted by several points of view (geological, structural, geophysical) from different studies [e.g., Borgia et al, 1992;Rust and Neri, 1996;Froger et al, 2001;Bonforte and Puglisi, 2003]. Besides its origin, all models point out that the eastward movement of the eastern flank is allowed by a detachment zone whose, geometry, depth and dipping is different from one model to other.…”

“…Three-dimensional (3-D) displacement data of the whole GPS data set were inverted by using a simple structural framework constituted by a spherical pressure source [Mogi, 1958] located beneath the summit area, and by a dislocating subhorizontal plane [Okada, 1985] located beneath the eastern flank. Although the Okada [1985] formalism seems to be an approximation to model a ground deformation pattern produced by a ''sliding'' source, it has been successfully applied both at Hawaii [e.g., Owen et al, 2000b;Cervelli et al, 2002] and Mount Etna [e.g., Bonforte and Puglisi, 2003] to perform a first-order modeling of the deformation pattern in similar conditions.…”

“…The time series of this network began in 1988 and from then on its configuration has been improved so that it now covers the entire volcanic area [Bonforte and Puglisi, 2003], with particular emphasis on the eastern and north eastern flank .…”

Thermal weakening of the carbonate basement under Mt. Etna volcano (Italy): Implications for volcano instability

“…Etna (e.g., Borgia et al, 1992;Bonforte and Puglisi, 2003;Rust et al, 2005;Bonforte and Puglisi, 2006;Palano et al, 2008;Palano et al, 2009), with an average rate, calculated from geodetic data collected at the Pernicana fault since 1997, of about 2.8 cm/year (Azzaro et al, 2001;Palano et al, 2009). A large décollement surface, potentially dictating this large-scale deformation by driving gravity-driven edifice spreading, has been…”

Modeling ground deformation associated with the destructive earthquakes occurring on Mt. Etna's southeastern flank in 1984

“…1 represents surface evidence related to NE-SW Messina-Fiumefreddo (MF) line, overlapping to the north with the ATL fault system (Palano et al, 2012, and references therein), while the faults of the "Timpe" system are the major tectonic surface manifestations of the ME. The interaction between regional stress, dike-induced rifting and gravity force is the cause of a fairly continuous and roughly eastward and downslope motion of its eastern flank (e.g., Puglisi and Bonforte, 2003;Solaro et al, 2010). Recent studies have investigated the interaction between flank deformation and local seismicity (Azzaro, 2004;Cannavò et al, 2015).…”