Publication Date:
2020-05-29
Description:
The Campi Flegrei caldera in southern Italy
is one of the greatest geohazard areas on Earth. Evidence
of an active magmatic and geothermal system is provided
by ongoing ground uplift, with volcano-tectonic and longperiod
(LP) seismicity, the persistent degassing of ~1500
tonnes of CO2 per day, the presence of hot fumaroles at
temperatures of 90–150 °C, brine-rich aquifers (with total
dissolved solids up to 33 g l−1) and high thermal gradients
in the crust (with temperatures reaching 420 °C at 3,050 m
b.s.l.). Since the 1940s, more than 100 exploratory boreholes
have been drilled in the area to depths of 80–3,100 m
by the Azienda Geologica Italiana Petroli (AGIP) and the
Società Anonima Forze Endogene Napoletane (SAFEN).
To date, however, no systematic reanalysis of the drilling
data has been carried out, and the buried volcanic structure
has not been updated using the most recent scientific
results and previous findings. By integrating unpublished
data from the AGIP and SAFEN reports with published
information from geological, volcanological, petrological,
petrophysical and geophysical studies, this paper presents
an improved picture of the Campi Flegrei caldera that
will be useful for volcanic hazard assessment and mitigation
in the Naples area and for future research planning The results suggest that intra-caldera activity has been
influenced by how the magmatic system at depths greater
than about 4 km has determined the transfer of magma,
volatiles, and heat to the overlying geothermal system and,
ultimately, to the surface. In particular, intriguing is that
the most volcanically active central-eastern sector of the
caldera, which is subject to intense bradyseismic ground
movement and gas emission, coincides with a structurally
delimited subsurface rock volume characterized by an
uprising of the 100 °C isotherm, a deep water supply to the
shallower aquifer, the early disappearance of secondary calcite,
LP seismicity and high seismic S-wave attenuation. In
this area, we also document evidence of repeated injection
at depths of c. 1.5–3.0 km of isolated and small-volume
batches of magma, where occurred their crystallization and
degassing. Shallow intrusions and degassing of magma are
thus identified as two of the key processes that drive unrest
in Campi Flegrei.
Description:
Published
Description:
401-421
Description:
1V. Storia e struttura dei sistemi vulcanici
Description:
JCR Journal
Description:
restricted
Keywords:
Volcanic system
;
Campi Flegrei
;
AGIP
;
Volcanic hazard
;
04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
