Publication Date:
2020-06-03
Description:
The ongoing unrest at the Campi Flegrei caldera (CFc) in southern Italy is prompting exploration
of its poorly studied offshore sector. We report on a multidisciplinary investigation of the Secca delle
Fumose (SdF), a submarine relief known since antiquity as the largest degassing structure of the offshore
sector of CFc. We combined high-resolution morphobathymetric and seismostratigraphic data with onshore
geological information to propose that the present-day SdF morphology and structure developed during
the initial stages of the last CFc eruption at Monte Nuovo in AD 1538. We suggest that the SdF relief stands
on the eastern uplifted border of a N-S-trending graben-like structure formed during the shallow emplacement
of the Monte Nuovo feeding dike. We also infer that the high-angle bordering faults that generated
the SdF relief now preferentially allow the ascent of hot brines (with an equilibrium temperature of 1798C),
thereby sustaining hydrothermal degassing on the seafloor. Systematic vertical seawater profiling shows
that hydrothermal seafloor venting generates a sizeable CO2, pH, and temperature anomaly in the overlying
seawater column. Data for the seawater vertical profile can be used to estimate the CO2 and energy (heat)
outputs from the SdF area at 50 tons/d ( 0.53 kg/s) and 80 MW, respectively. In view of the cause-effect
relationship with the Monte Nuovo eruption, and the substantial gas and energy outputs, we consider that
the SdF hydrothermal system needs to be included in monitoring programs of the ongoing CFc unrest.
Description:
Published
Description:
4153–4178
Description:
1V. Storia e struttura dei sistemi vulcanici
Description:
JCR Journal
Description:
restricted
Keywords:
Hydrothermal fluid
;
Campi Flegrei caldera
;
04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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