Ground deformation at Campi Flegrei, Italy: implications for hazard assessment

Abstract

Campi Flegrei caldera, west of Naples in southern Italy, has an exceptional documented record of ground deformation from Roman times onwards. Systematic recording began in the nineteenth century. For earlier dates, information has been obtained from archaeological studies and from contemporary descriptions of the locations of buildings, usually Roman, with respect to sea-level. Especially important have been accounts related to the Serapis, a Roman market-place built in the second century BC and now incorporated within the modern town of Pozzuoli. The long-term patterns of ground deformation have conventionally been investigated on the premise that Campi Flegrei naturally tends to a state of static equilibrium. This study argues that, instead, the area naturally tends to a steady rate of subsidence, at about 17 mm a -~. After this background rate has been removed, the data indicate that a permanent uplift of some 33 m has occurred from Roman times (up until the present day: 2005 at the time of writing), attributable to the intrusion of 1.85 km 3 of magma, of which only 1% has been erupted. Uplift has occurred in three episodes, the third of which is still in progress. The behaviour can be interpreted in terms of the intermittent ascent of magma between a reservoir of c. 102-103 km 3 at depths of 8-15 km or greater, to a much smaller, shallower system at depths of about 34 km. Should the current pattern of deformation follow previous trends, uplift is expected to continue for another 80-90 years, during which time Campi Flegrei will be characterized by an elevated possibility of eruption.

Late Quaternary deformation on the island on Pantelleria: New constraints for the recent tectonic evolution of the Sicily Channel Rift (southern Italy)

“…During Late Holocene times, doming was the result of at least three distinct uplift events that inverted the uniform subsidence state likely associated with magma intrusions along NNE-SSW crustal cracks within the shallow-depth reservoir(s) of the south-eastern part of the island. The vertical deformations of Pantelleria also indicate a magmatic behavior similar to that described for the Campi Flegrei Caldera (Bellucci et al, 2006) thus implying that the island in the last 5 ka has been dominated by intrusion processes rather than eruptive activity. M a n u s c r i p t A c c e p t e d M a n u s c r i p t …”

“…Considering that an analogous behavior characterized by uplift and subsidence has been detected Page 11 of 27 A c c e p t e d M a n u s c r i p t for the Campi Flegrei Caldera (Bellucci et al, 2006), we propose a similar mechanism for the Pantelleria caldera complex. In this view the subsidence should represent the typical background state of the area interrupted by discrete and faster uplift events related to magma intrusions.…”

Distributed-Temperature-Sensing Using Optical Methods: A First Application in the Offshore Area of Campi Flegrei Caldera (Southern Italy) for Volcano Monitoring

“…Since Roman times, the caldera area has been characterized by slow aseismic subsidence [27,28], which has been interrupted by recurring phases of rapid uplift. Several phases of uplift have occurred since the Middle Ages, including the Monte Nuovo eruption (AD 1538; 0.02 km 3 DRE) and, in recent times, during 1970-1972 and 1982-1984 when the town of Pozzuoli was raised by 1.7 and 1.8 m, respectively [29][30][31].…”

“…Sacchi et al, (2014) [24] also show that a dome structure, correlated to the resurgence of the caldera, is centered in the Bay of Pozzuoli about 1.7 km south of Pozzuoli Harbor. This sector is marked by the presence of minor, normal faults that subsided the apical dome possibly by diffuse pore fluid circulation along the higher permeability zones [24][25][26][27][28][29][30][31][32]. As regards the thermal state of the caldera, there is surface evidence of the presence of a high temperature geothermal system, which is mainly developed in the central part of the caldera at Solfatara crater [6][7][8][9][10][11].…”

New seismo-stratigraphic and marine magnetic data of the Gulf of Pozzuoli (Naples Bay, Tyrrhenian Sea, Italy): inferences for the tectonic and magmatic events of the Phlegrean Fields volcanic complex (Campania)

“…A correlation with the terrestrial geology of the Phlegrean Fields has been attempted in order to highlight tectonic and magmatic implications in the geological evolution of the Phlegrean Fields volcanic complex, intensively studied through field geology (Morhange et al 2005;Bellucci et al 2006;De Natale et al 2007;Bodnar et al 2007). …”