Spatial and temporal distribution of vertical ground movements at Mt. Vesuvius in the period 1973-2009

Abstract

<p>Since the early ’70s vertical ground movements at Mount Vesuvius area have been investigated and monitored by the Osservatorio Vesuviano (Isti-tuto Nazionale di Geofisica Vulcanologia - Osservatorio Vesuviano since 2001). This monitoring began with the installation of a high-precision leveling line in the region at medium-high elevations on the volcano. The deformation pattern and expected strain field assessment methods in the volcanic structure induced by inner sources has demanded in subsequent years the expansion of the leveling network up to cover the whole volcanic area, enclosing part of leveling lines of other institutions. As a result of this expansion, the Mt. Vesuvius Area Leveling Network (VALN) has today reached a length of about 270 km and consists of 359 benchmarks. It is configured in 21 circuits and is connected, westward, to the Campi Flegrei leveling network and, northward, to the Campania Plain leveling network. The data collected have been carefully re-analyzed for random and systematic errors and for error propagation along the leveling lines to identify the areas affected by significant ground movements. For each survey, the data were rigorously adjusted and vertical ground movements were evaluated by differentiating the heights calculated by the various measurements conducted by the Osservatorio Vesuviano from 1973 to 2009.</p>

The Ground Deformation History of the Neapolitan Volcanic Area (Campi Flegrei Caldera, Somma–Vesuvius Volcano, and Ischia Island) from 20 Years of Continuous GPS Observations (2000–2019)

“…From Vesuvius to Somma, the subsidence rate decreases until reaching the minimum values on the coast. These values are in agreement with data from the tide gauge network [78] and from the levelling measurements [68]. These last two considerations show how the vertical displacements are influenced by the topography of the volcano [79,80].…”

“…A power law plus white noise model was used, and an annual and semiannual seasonal signal were estimated and removed. All stations display a general subsidence, with higher values on the summit volcano edifice [43,68]. Only the BKNO, BKE1, and OSVE stations have significant horizontal displacements; the other stations show negligible horizontal trends.…”

Somma Vesuvius volcano: ground deformations from CGPS observations (2001-2012)

“…Somma, the subsidence velocity decreases until reaching the minimum values on the coast, where the station at a lowest altitude (AGR1) has a velocity (−0.28 ± 0.24 mm/year) comparable to the error. This is confirmed by data from the tide gauge network [Tammaro et al 2007, Obrizzo et al 2009] and from the leveling network [Pingue et al 2013]. Comparison between the velocity of the leveling benchmarks close to GPS stations and UP velocity of GPS sites is shown in Figure 5 and Table 4.…”

“…The results obtained (Figure 8) indicate, as already in the past [Bonasia and Pingue 1981] that Somma-Vesuvius is affected by a predominant contraction phase, albeit small (less than 10 ppm). This contraction phase is more marked (Figure 8) in the areas with the greatest altitudes, according to the phenomenon of diffuse and modest subsidence observed in the Gran Cono area [Bonasia and Pingue 1981 Pingue and Esposito 1988, Pingue et al 1998, Lanari et al 2002, Pingue et al 2013.…”

Defining the Pre-Eruptive States of Active Volcanoes for Improving Eruption Forecasting

“…In some cases, seismic activity correlates with an increase in the CO 2 flux linked to the migration of deep fluids in the hydrothermal system of the central conduit (Del Pezzo et al, 2013). The entire edifice and particularly the summit caldera are characterized by continuous subsidence of ~1 cm/yr (Figure 6; De Natale et al, 2006;Folco Pingue et al, 2013;. The fumarolic activity is weak and confined at the summit of the cone, with diffuse degassing of ~150 t/day of CO 2 both magmatic and deriving from thermal decarbonation (Iacono Marziano et al, 2009;Granieri et al, 2013).…”