The 2002–2003 submarine gas eruption at Panarea volcano (Aeolian Islands, Italy): Volcanology of the seafloor and implications for the hazard scenario

A submarine gas eruption started in November 2002 offshore of Panarea volcano (Aeolian Islands, Italy). The intensity of the
gas emission and the considerable anomalies of the geochemical and geophysical parameters have alarmed the volcanological
community and the Italian Civil Protection Agency on the possibility that this activity may represent a volcanic unrest at Panarea
volcano. We used a high resolution Marine Digital Terrain Model (MDTM), with 0.5 m accuracy, and detailed underwater surveys
by scuba diving to study the exhalation centres and the geological, morphological and structural features of the seafloor and to
clarify the relationships between gas vents distribution, submarine volcanological structures and the recent deformation of this area.
The underwater surveys revealed an exhalative field characterised by 21 main active gas vents and craters from metres to tens of
metres in diameter, and a pervasive exhalation from the seafloor; hundreds of fossil craters associated with gas pipes and
hydrothermal alteration are also present on the seafoor: craters, pipes and conduits are not associated with juvenile deposits and
relate to a long standing history of gas exhalation and eruptions.
We present the first geological sketch map of the seafloor surrounding the exhalative area and establish the role of NE- and NWtrending
fractures as the main pathways for the gas exhalation.

Anzidei, M., 2000. Rapid bathymetric surveys in marine volcano
areas: a case study in Panarea aera. Phys. Chem. Earth, Part A
Solid Earth Geod. 25 (1), 77– 80.
Anzidei, M., Esposito, A., 2003. New insights from resolution bathymetric
surveys in the Panarea Volcanic Complex. Geophys. Res.
Abstr., vol. 5. EGS, Nizza, p. 05923. http://www.cosis.net/
abstracts/EAE03/05923/EAE03-J-05923.pdf.
Anzidei, M., Esposito, A., Bortoluzzi, G. and De Giosa, F., in press.
High resolution Bathymetric map of the exhalative area of Panarea
(Aeolian Islands, Italy). Ann. of Geoph..
Barberi, F., Gasparini, P., Innocenti, F., Villari, L., 1973. Volcanism of
the southern Tyrrenian sea and its geodynamic implications. J.
Geophys. Res. 78, 5221– 5232.
Beccaluva, L., Gabbianelli, G., Lucchini, F., Rossi, L., Savelli, C.,
1985. Petrology and K/Ar ages of volcanics dredged from the
Eolian seamounts: implications for geodynamic evolution of the
southern Tyrrhrnian basin. Earth Planet. Sci. Lett. 74, 187– 208.
Bellia, S., Carapezza, M., Italiano, F., Nuccio, P.M., 1986. Caratteristiche
delle emissioni geotermiche sottomarine ad Est di Panarea
(Isole Eolie). Proceedings of the V Italian Conference,GNGTS. ,
p. 1191– 1202.
Bellia, S., Italiano, F., Nuccio, P.M., 1987. Le strutture sommerse ad
est di Panarea Isole Eolie: definizione di una loro natura antropica
sulla base di studi mineralogici, petrografici e geochimici, vol. 3.
I.G.F. C.N.R., Palermo.
Calanchi, N., Capaccioni, B., Martini, M., Tassi, F., e Valentini, L.,
1995. Submarine gas-emission from Panarea Island Aeolian
Archipelago: distribution of inorganic and organic compounds
and inferences about source conditions. Acta Vulcanol. 7 (1),
43–48.
Calanchi, N., Tranne, C.A., Lucchini, F., Rossi, P.L., Villa, I.M.,
1999. Explanatory notes to the geological map (1 : 10.000) of
Panarea and Basiluzzo islands (Aeolian arc. Italy). Acta Vulcanol.
11 (2), 223– 243.
Calanchi, N., Peccerillo, A., Tranne, C.A., Lucchini, F., Rossi, P.L.,
Kempton, P., Barbieri, M., Wu, T.W., 2002. Petrology and geochemistry
of volcanic rocks from the island of Panarea: implications
for mantle evolution beneath the Aeolian island arc
(southern Tyrrhenian sea). J. Volcanol. Geotherm. Res. 115,
367–395.
Caliro, S., Caracausi, A., Chiodini, G., Ditta, M., Italiano, F., Longo,
M., Minopoli, C., Nuccio, P.M., Paonita, A., Rizzo, A., 2004.
Evidence of a new magmatic input to the quiescent volcanic
edifice of Panarea, Aeolian Islands, Italy. Geophys. Res. Lett.
31, L07619. doi:10.1029/2003GL019359.
Capaccioni, B., Rossi, P.M.L., Tassi, F., Tedesco, D., Vaselli, O.,
2003. Risultati delle osservazioni geochimiche presso l’isola di
Panarea in seguito all’evento di degassamento sottomarino del 3
novembre 2002. Abstract, GNV General Assembly, p. 17.
Caracausi, A., Ditta, M., Italiano, F., Longo, M., Nuccio, P.M.,
Paonita, A., 2004. Massive submarine gas output during the
volcanic unrest off Panarea Island(Aeolian arc, Italy): inferences
for explosive conditions. Geochim. J. 39 (05), 459– 467. (http://
www.terrapub.co.jp/journals/GJ/frame/39.html).
Caramanna, G., Carapezza, M.L., Cioni, R., Cardellini, F., Cinti, D.,
Lelli, M., Pizzino, L., Quattrocchi, F., Voltattorni, N., 2003. Primi
sei mesi di monitoraggio delle diverse fasi (solida-liquida e gassosa)
presso le esalazioni sottomarine di Panarea a partire dal
novembre 2002. Abstract, GNV General Assembly, p. 19.
Chiodini, G., Avino, R., Caliro, S., Caramanna, G., Granirei, D.,
Monopoli, C., Moretti, R., Perrotta, L., Russo, M., 2003. Geochimica
delle emissioni gassose sottomarine di Panarea: origine
magmatica vs idrotermale ed implicazioni per la sorveglianza
vulcanica. Abstract, GNV General Assembly, p. 14.
De Astis, G., Ventura, G., Vilardo, G., 2003. Geodymanic significance
of the Aeolian volcanism (Southern Tyrrhenian Sea, Italy)
in light of structural, seismological and geochemical data. Tectonics
22 (4), 1040. doi:10.1029/2003TC001506.
Falsaperla, S., Lanzafame, G., Longo, V., Spampinato, S., 1999.
Regional stress field in the area of Stromboli (Italy): insights
into structural data and crustal tectonic earthquakes. J. Volcanol.
Geotherm. Res. 88, 147– 166.
Gabbianelli, G., Gillot, P.Y., Lanzafame, G., Romagnoli, C., Rossi,
P.L., 1990. Tectonic and volcanic evolution of Panarea (Aeolian
Island, Italy). Mar. Geol. 92, 312–326.
Gabbianelli, G., Romagnoli, C., Rossi, P.L., Calanchi, N., 1993. Mar.
Geol. of Panarea–Stromboli area. Aeolian Archipelago, Southeastern
Tyrrhenian sea. Acta Vulcanol. 3, 11 –20.
Gamberi, F., Marani, P.M., Savelli, C., 1997. Tectonic volcanic and
hydrothermal features of submarine portion of Aeolian arc (Tyrrhenian
Sea). Mar. Geol. 140, 167– 181.
Gillot, P.Y., 1984. Datation par la methode du potassium-argon de
roches volcaniques recentes (Pleistocenes et Holocenes). Contributions
a l’etude chronostratigraphique et magmatique des provinces
volcaniques de la Campania, des Iles Eoliennes, de
Pantelleria (Italie du Sud) et de la Reunion (Ocean Indien).
These Doct. Sci., Uni. Oaris Sud Paris, 249 pp.
Italiano, F., Nuccio, P.M., 1991. Geochemical investigations of submarine
volcanic exhalations to the east Panarea, Aeolian Islands,
Italy. J. Volcanol. Geotherm. Res. 46, 125–141.
Lucchi, F., Tranne, C.A., Calanchi, N., Keller, J. and Rossi, P.L.
2003., Geological map of Panarea and minor islets (Aeolian
Islands). University of Bologna, University of Freiburg and
INGV, L.A.C. Firenze.
Mercalli, 1883. Vulcani e fenomeni Vulcanici. In: Negri, G., Stoppani,
A., Mercalli, G. (Eds.), Geologia d’Italia 3rd part. Milano,
374 pp.
Newhall, C.G., Albano, S.E., Matzumoto, S.N., Sandoval, T., 2001.
Roles of Groundwater in volcanic unrest. J. Geol. Soc. Phil. 56,
69– 84.
Romano, R., 1973. Le isole di Panarea e Basiluzzo. Riv. Min. Sicil.
139–141, 49– 86.
Saccorotti, G., Galluzzo, D., La Rocca, M., del Pezzo, E., Patane`, D.,
2003. Monitoraggio dell’attivita` sismica a Panarea. Abstract,
GNV General Assembly, Roma 9–11 June.
Storia Geofisica Ambientale, 1996. Fenomeni vulcanici nell’arcipelago
delle Eolie dall’antichita` al XX secolo. Studio di fattibilita`
RPT, vol. 156,96. Bologna, Italy.
Tallarico, A., Dragoni, M., Anzidei, M., Esposito, A., 2003. Modeling
long-term round deformation due to the cooling of a magma
chamber: case of Basiluzzo island, Aeolian islands, Italy. J. Geophys.
Res. 108 (B 12), 2568. doi:10.1029/2002JB002376.
Todesco, M., Chiodini, G., Macedonio, G., 2003. Monitoring and
modelling hydrothermal fluid emission at La Solfatara (Phlegreran
Fields, Italy). An interdisciplinary approach to the study of diffuse
degassing. J. Volcanol. Geotherm. Res. 125, 57– 79.
Tranne, C.A., Lucchi, F., Calanchi, N., Lanzafame, G., Rossi. P.L.,
2002a, Geological map of the island of Lipari (Aeolian Islands):
University of Bologna and INGV, printed by L.A.C., Firenze.
Tranne, C.A., Lucchi, F., Calanchi, N., Rossi, P.L., Campanella, T.,
Sardella, A., 2002b, Geological map of the island of Filicudi
(Aeolian Islands): University of Bologna and INGV, printed by
L.A.C., Firenze.