Italy's Volcanoes: The Cradle of Volcanology

Campi Flegrei caldera

 
Geology References Web sites


Solfatara crater

Part of the crater floor of Solfatara, near Pozzuoli

Campi Flegrei caldera, Campania, Italy

volcano number: 0101-01=

summit elevation: 458 m

location: 40.827N, 14.139E

 

Introduction


Geological map

Geological sketch map of the Campi Flegrei caldera, kindly supplied by Roberto Scandone of Roma, Terza Università.

The volcano of Campi Flegrei lies immediately to the west of Napoli, and its deposits form much of the hills on which the higher areas of that city have been constructed. Less conspicuous as a volcano than neighboring Vesuvio, the Campi Flegrei must be considered one of the most dangerous volcanoes in Italy, mostly because of continuing unrest and dense population within the caldera and in its immediate vicinity.

Volcanism has occurred in the Campi Flegrei area during the past 50 ka, including two extremely violent explosive eruptions, the one that erupted the Campanian ignombrite (35 ka ago) and another one only 12 ka ago which produced the Neapolitan Yellow Tuff. The erupted volumes show a general decrease with time, and the most recent eruptions were characterized by moderate to small volumes.

Pozzuoli deserted

Damaged and abandoned houses in the center of Pozzuoli town, September 1989. Five years after the end of the bradyseismic crisis, signs of reoccupation in the city are visible, but much of the city presents a quite desolate aspect. Loudspeakers are visible in the photo. In May 1996, loudspeakers were no longer present, reconstruction and repair work was vigorous, and the buildings visible in this image had been completely redone and dyed.

The Campi Flegrei caldera is well known for a phenomenon named "bradyseism" which is the alternating uplift and sinking of the ground within the caldera. Several dramatic episodes of uplift are known from the past 300 years, one of them has culminated in an eruption so far, in 1538, when the most recent volcanic feature of the Campi Flegrei was born, Monte Nuovo, "the new Mountain". Renewed uplift in the 1970's and 1980's has not been followed by an eruption but has triggered intense efforts for a better understanding of such complex volcanic systems, and led to detailed hazard assessments.

Epicenter map

Epicenter map of 1982-1984 seismicity around Pozzuoli. Note that the densest clustering of earthquakes coincides with the Solfatara crater, immediately north of the city. This map was kindly supplied by Roberto Scandone.

Solfatara

Solfatara crater near Pozzuoli. Boiling mud is visible at the bottom of this small (2 m diameter) pit, during a period of decreasing activity in September 1989. Much more intense activity at this mudpot was observed during the 1982-1984 seismic crisis.

All present activity in Campi Flegrei is limited to fumarolic steam emission and mud boiling and sputtering, occurring in the famous Solfatara crater (see intro photo at top of this page and image above this paragraph). The crater gave name to the kind of activity observed within it ("solfataric" activity), a term used worldwide until recently. Because of frequent overlap with the activity named "fumarolic", it has been proposed (in Volcanoes of the World, 1994 edition) to abandon the term "solfataric activity" and use "fumarolic" instead.

City between craters

Photo looking from the Posillipo hill down on the densely populated and industrialized westernmost part of Napoli, lying absurdly stuffed between volcanic hills and craters of the Campi Flegrei volcanic field. The low vegetated ridge visible in the center of the photo is the rim of Agnano crater, site of a major Plinian eruption about 4400 years ago.

Hazards

Campi Flegrei (and its eastward extension into the area of the city of Napoli) are considered a potentially highly dangerous volcanic area. The presence of large numbers of people in that area (the town of Pozzuoli and part of Napoli as well as numerous smaller settlements) present an irresolvable problem to authorities and scientists in the case of imminent danger. Pozzuoli lies close to the Solfatara crater and above the deposits of numerous eruptions of the past few tens of ka. Napoli, with about 2 million inhabitants, lies peculiarly between the Campi Flegrei and Vesuvio both of which have left their deposits in the city area, and has a small volcanic center in its SW part (Cole et al. 1994). There is no reason to assume that one of these volcanic centers has permanently ceased erupting. More, and among them, large, eruptions are to be expected at Campi Flegrei as well as at Vesuvio, and also from the volcanic centers in the Posillipo and Vomero-Bay of Chiaia area of Napoli (St. Elmo lava dome, Chiaia tuff cones, and Monte Echia volcano). A vent may erupt in the future from the Bay of Chiaia, as suggested by Cole et al. (1994).

References (very few so far, more to follow)

Cole, P.D.; Perrotta, A. & Scarpati, C. (1994) The volcanic history of the southwestern part of the city of Naples. Geological Magazine 131: 785-799.

Di Filippo, G.; Lirer, L.; Maraffi, S. & Capuano, M (1991) L'eruzione di Astroni nell'attività recente dei Campi Flegrei. Bollettino della Società Geologica Italiana 110: 309-331.

Di Vito, M.; Lirer, L.; Mastrolorenzo, G. & Rolandi, G. (1987) The 1538 Monte Nuovo eruption (Campi Flegrei, Italy). Bulletin of Volcanology 49: 608-615.

Mastrolorenzo, G. (1994) Averno tuff ring in Campi Flegrei (south Italy). Bulletin of Volcanology 56: 561-572.

Rosi M & Santacroce R (1984) Volcanic Hazard Assessment in the Phlegrean Fields: a Contribution Based on Stratigraphic and Historical Data. Bulletin Volcanologique 47: 359-370

Rosi M, Sbrana A & Principe C (1983) The Phlegrean Fields: Structural evolution, Volcanic History and Eruptive Mechanisms. Journal of Volcanology and Geothermal Research 17: 273-288

Web sites

A new website dedicated to Monte Nuovo has appeared, giving background info about Neapolitan and Campi Flegrei volcanism, the eruption of Monte Nuovo, and its vegetation. This is in Italian but definitely worth a check.

Roberto Scandone who has kindly submitted much material to these pages has created his own homepage about the Neapolitan volcanoes, including Campi Flegrei. This page has much info not present on the Campi Flegrei page of "The Cradle of Volcanology".

Campnet Informatica offers Virtual Tour of Campi Flegrei. See for example the historical images of the 1538 Monte Nuovo eruption

This touristic site about Campi Flegrei has a separate page with numerous photos

Copyright © Boris Behncke, "Italy's Volcanoes: The Cradle of Volcanology"

Page set up on 31 May 1996, last modified on 7 February 2004
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