Table Of ContentActive Volcanoes of the World
Giovanni Orsi
Massimo D’Antonio
Lucia Civetta
Editors
Campi
Flegrei
A Restless Caldera in a Densely Populated Area
Active Volcanoes of the World
Series Editors
Corrado Cimarelli, Section for Mineralogy, Petrology and Geochemistry,
Ludwig-Maximilians-University Munich, Department of Earth and
Environmental Sciences, München, Germany
Sebastian Muller, Mineralogisches Museum, Marburg, Hessen, Germany
About 500 active volcanoes presently exist on the Earth’s surface, of which
around 50 erupt each year. Volcanoes played a crucial role in the evolution
of the planet and early life, and are constantly reshaping the morphology of
Planet Earth. Many active volcanoes are located in dense settlement areas,
with over 500 million people living in close proximity of still active or
dormant volcanoes.
On one side, volcanoes provide valuable soil and rock basis for
agriculture, but often the “mountains of fire” cause disastrous societal and
economicaldisasterscausedbyashclouds,lahars,lavaflows,andpyroclastic
flows. Eruptions are still difficult to predict, although volcanologists around
the world are constantly working on new ways to understand the character
and behavior of volcanoes.
ActiveVolcanoesoftheWorldisanofficialbookseriesoftheInternational
AssociationofVolcanologyandChemistryoftheEarth’sInterior(IAVCEI).
The series aims to be a scientific library of monographs that provide
authoritative and detailed reviews of state-of-the art research on individual
volcanoes or a volcanic area that has been active in the last 10.000 years,
e.g.theTeideVolcanoortheChiapasRegion.Thebooksintheseriescover
the geology, eruptive history, petrology and geochemistry, volcano moni-
toring, risk assessment and mitigation, volcano and society, and specific
aspects related to the nature of each described volcano.
The Active Volcanoes of the World series contains single and
multi-authored books as well as edited volumes. The Series Editors,
Dr. Corrado Cimarelli and Dr. Sebastian Müller are currently accepting
proposals and a proposal document can be obtained from the Publisher,
Dr. Annett Buettner ([email protected]).
Moreinformationaboutthisseriesathttps://link.springer.com/bookseries/10081
’
Giovanni Orsi (cid:129) Massimo D Antonio (cid:129)
Lucia Civetta
Editors
Campi Flegrei
A Restless Caldera in a Densely
Populated Area
123
Editors
GiovanniOrsi Massimo D’Antonio
Dipartimento di Scienzedella Terra Dipartimento di Scienzedella Terra
dell’Ambienteedelle Risorse dell’Ambienteedelle Risorse
Universitàdegli Studi diNapoli Universitàdegli Studi diNapoli
Federico II Federico II
Naples, Italy Naples, Italy
LuciaCivetta
Emeritus Professorof Geochemistry
andVolcanology
Universitàdegli Studi diNapoli
Federico II
Naples, Italy
ISSN 2195-3589 ISSN 2195-7029 (electronic)
ActiveVolcanoes of the World
ISBN978-3-642-37059-5 ISBN978-3-642-37060-1 (eBook)
https://doi.org/10.1007/978-3-642-37060-1
©Springer-VerlagGmbHGermany,partofSpringerNature2022
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Foreword
Campi Flegrei is a location of rich human history that is intertwined with
volcanism. As a volcanologist, I am drawn to the area for the wide range of
eruptive activity that has occurred there over the past several tens of thou-
sands of years. This ranges from the super-eruption that produced the
widespreadCampanianIgnimbrite,tothesmall(byvolcanologicalstandards)
cone-forming eruption of Monte Nuovo in the sixteenth century. The two
large nested calderas (related to the Campanian Ignimbrite and to the
NeapolitanYellowTuff)thathosttheCampiFlegreihaveexperiencedunrest
—indicative of a living volcanic system—throughout the human habitation
of the area, with multiple episodes of uplift and subsidence (inflation and
deflation). Many volcanologists have lodged at the campground in Solfatara
Crater, with its fumaroles that display another sign of the living volcano—
Campi Flegrei’s active hydrothermal system.
Volcanic activity has benefitted humans in many ways at Campi Flegrei,
for example with coastal craters forming beautiful protected harbours for
trading and military sea vessels, the rich volcanic soils, and abundant tuffs
that form excellent building materials. At the same time, volcanism poses a
majorrisktothedensepopulationofNaplesthatspillsintotheCampiFlegrei
and to the towns within it, especially since previous eruptions have been
dominated by dangerous explosive phenomena, such as pyroclastic density
currents and widespread tephra fall. This large human population, and the
living nature of the volcanic system, make the Campi Flegrei an area with
one of the highest volcanic risks on Earth.
Tremendousresearchhasbeenconductedovertheyearstounderstandthe
volcanic and human history of the area. Painstaking work has led to the
development of a robust geologic framework of the eruptive history of the
volcanic field. This framework facilitates detailed studies of the past and
current magmatic–hydrothermal processes, using a range of approaches that
include petrology, heat flow, geophysics, deformation monitoring, fumarole
and water chemistry, and numerical and experimental modelling. Distal
studies of Campi Flegrei tephra layers provide important Pleistocene
geochronologic makers over a wide portion of Europe, aiding in interpreta-
tion of Quaternary geology and prehistoric human activity. All of this pro-
vides necessary constraints for assessments of volcanic hazards as well as
geomorphic hazards such as landslides, which are common in rugged vol-
canicareaswithabundantaltereddeposits(andexasperatedbyurbanisation).
v
vi Foreword
This book integrates the huge body of existing research on the Campi
Flegrei.Thefocusisonvolcanismandvolcanichazards,butchaptersonthe
practical uses of volcanic materials in the area and the history of human
habitationnicelyroundoutthework.Thebookisaninvaluableresourcefor
allthoseconductingresearchontheCampiFlegreivolcanicsystemandasa
launching point for future researchers in the coming decades.
Greg A. Valentine
Department of Geology
and Center for Geohazards Studies
University at Buffalo
Buffalo, NY, USA
Introduction
In the history of the European culture, Campi Flegrei represent the myth of
RomecelebratedintheAeneidbyVirgil(70BC–19BC),whomadeAeneas,
theTrojanherooftheGreco-Romanmythologyandprogenitorofthefamily
ofEmperorAugustus,disembarkinCuma.Travellersofalltimeshavebeen
lookingforthemythandnotforthehistoryonthePhlegraeanshores.Among
them, Francesco Petrarca (AD 1304–1374), who wrote about his journey to
the Campi Flegrei in AD 1343: “I have seen all the places of Virgil”.
The Campi Flegrei are a magical place within the Mediterranean where
striking volcanic phenomena, inexplicable to the ancients, have fuelled the
myth for millennia. Local history, stories, legends, literature form an
IntangibleCulturalHeritageofthehumanitythattheCampiFlegreipreserve.
However,forthisheritagetobewellunderstoodandinterpretedtodayandin
future, we are called to take care of the natural features from which it was
generated.
The Campi Flegrei are also one of the best places in the world where to
find the effects of the encounter-clash between nature and Man, the species
presently dominant on Earth. Since millennia, they are a privileged scenery
for this encounter-clash with phases of strong anthropisation and slow but
unrestrainable volcanic events. Among these, the best known and somehow
specific is the bradyseism that testifies “the breath of the Earth” and causes
ground uplift and subsidence with birth or disappearance of pieces of land
and environmental changes.
Despite the presence of three active Volcanoes (Campi Flegrei,
Somma-Vesuvio, Ischia) with the direct and related potential hazards they
pose, the Neapolitan area has been inhabited by humans since Neolithic
times. The earliest organised society developed with the settlement of
Hellenic colonies in the eighth century BC at Ischia, Cuma in the Campi
Flegrei,andMegarideisletclosetothecoastofthecityofNaples,andinthe
sixth century BC at Pozzuoli. Presently, the area hosts a population of more
than two million people for a variety of reasons, among which soil fertility,
temperate climate, beautiful scenery, abundance of thermo-mineral waters
and easily extractable volcanic rocks suitable for being used for engineering
andarchitecturalpurposes.Furthermore,thearea,locatedrightinthemiddle
oftheMediterranean,thecradleoftheWesternCulture,hasbeenalwaysina
very favourable position from a political, commercial and strategic point of
view. The millenary coexistence of volcanic phenomena and human’s
activity has determined the basic conditions for the development and
vii
viii Introduction
conservationofanextraordinarybiodiversityontheoutskirtsofNaples,one
of the most densely populated European urban areas.
Calderas are depressions that occur in all volcanic environments and
geodynamic settings on Earth as well as on other planets, with a diameter
larger than that of the explosive vents or craters. Topics such as formation
and evolution of calderas, including pre-collapse tumescence, collapse and
post-collapse resurgence, are still debated in the scientific literature. Caldera
collapsesrepetitivelyoccurringinthesamearea afterseveral eruptions form
nested collapse structures. Presently, 97 out of the 446 calderas known on
Earth are in unrest. Volcanic unrest is the deviation of a given volcano, in
particular of its manifestations, such as ground deformation, degassing,
seismicity and gravity acceleration, relatively to its baseline. It is likely
generated by pressure and/or volume increase in the magmatic or
hydrothermal system, variation in the local stress field or by a combination
of more than one of them.
The Campi Flegrei, to the west of and partially including the city of
Naples, give name to the Campi Flegrei volcanic field which dominant
featureistheCampiFlegreicaldera,anested,resurgentandrestlessstructure
in the densely inhabited Neapolitan volcanic area, within the Campanian
Plain.TheearlieststudiesonthevolcanismoftheNeapolitanareadateback
to the eighteenth century. The book “Campi Phlegraei. Observations on the
volcanosoftheTwoSicilies”bySirWilliam Hamilton, British Ambassador
to the Kingdom of Naples from 1764 to 1800 and volcanologist, was
published in 1776 in French and English because it was intended for the
travellersoftheGrandTour.Actually,itisthefirstcomprehensivedocument
on the volcanoes of Southern Italy. Scipione Breislak, an Italian geologist
and naturalist, presented the results of his studies in the book “Topografia
FisicadellaCampania”publishedin1798.TheNeapolitanvolcanicareahas
also attracted the interest of other outstanding scientists such as Johnston
Lavis (1889), Dell’Erba (1892), De Lorenzo (1904) and Rittmann (1950).
ThelatterwasthefirsttoenvisagethepresenceofacalderainthePhlegraean
area. Since then, timing, geometry and evolution of the Campi Flegrei
caldera and its magmatic feeding system have been variably interpreted by
manyauthors.Themostsharedideaamongthescientificcommunityisthatit
isacomplex,nestedandresurgentstructureresultingmainlyfromtwomajor
collapsesrelatedtothecatastrophicCampanianIgnimbrite(*40ka)andthe
Neapolitan YellowTuff(*15ka)eruptions. The youngestofthese calderas
is the portion still active of the entire system. One part of this caldera is
submerged. This makes both basic research and monitoring more difficult.
Only since few years, researches on the submerged portion of the caldera
have beenintensifiedby deployingsea-bottom, multi-parametric stations for
monitoring and carrying out offshore seismic and morphological surveys.
The youngest caldera has been the site of an intense volcanism and
deformationinthepast15kyrs.Thevolcanismhasgeneratednotlessthan70
eruptions, most of which have been explosive, with phreatomagmatic
dominatingovermagmaticexplosions.Thedeformationhasmostlyconsisted
in resurgence of the floor of the younger caldera with a maximum net uplift
of about 100 m. The caldera floor is affected by short-term deformation
Introduction ix
episodes, also known as bradyseismic events. The earliest evidence of this
phenomenon prior to the installation of a monitoring system in the area has
been recognised atthe Serapeo inPozzuoli,the remnant ofa Roman market
which oldest part was built in the first century AD and reported by Antonio
Parascandola inalandmarkpaper published in1947.Themostrecent major
events have occurred in 1969–1972 and in 1982–1984 totalling a maximum
netuplift of350 cmatPozzuoli.Theseevents,whichstimulated theinterest
ofmanyscholarsonthecaldera,havebeenfollowedbysomeminorepisodes
known as miniuplifts. The last of these episodes began in late 2004 and is
still ongoing. These bradyseismic events have been interpreted as transient
short-term deformation events within the long-term deformation. The
magmatic feeding system has a complex architecture with melts stagnating,
differentiating, mingling and mixing at various depths. It includes a
widespread reservoir at about 8–10 km depth that feeds smaller magma
chambers at depths varying between 2 and 8 km that in turn feed the
eruptions.Atshallowerdepthisanactivehydrothermalsystemthatgenerates
diffuse soil degassing, as well as fumarole and hot-water spring activity,
especially at Solfatara and Pisciarelli localities.
The persistent state of activity, testified by the current unrest, and the
explosive character of volcanism result in a high level of volcanic hazard
potentialofthecaldera.Thedenseurbanisation,withapopulationofnotless
than 350,000 people in the most active portion of the caldera, determines a
very high risk. In this situation, the Italian Dipartimento della Protezione
Civile (www.protezionecivile.it) in 2012 has increased the alert level from
Base to Attention, the second of 4 levels provided by the Campi Flegrei
National Emergency Plan.
Thisbookaimsatpresentingthecurrentandmostwidelysharedknowledge
ofthescientificcommunityengagedinthestudyofthevariousaspectsofthe
CampiFlegreicaldera.Inparticular,thevolcanicanddeformationhistory,as
well as the present setting of the caldera defined through geological and
volcanological (Chap. “Volcanic and Deformation History of the Campi
FlegreiVolcanicField,Italy”)andgeophysical(Chap.“SeismicandGravity
Structure of the Campi Flegrei Caldera, Italy”) studies, is summarised.
Another topic extensively treated concerns the evolution through time,
architecture and current state of the magmatic feeding system (Chaps. “An
EvolutionaryModelfortheMagmaticSystemoftheCampiFlegreiVolcanic
Field(Italy)ConstrainedbyPetrochemicalData”,“OriginandDifferentiation
History of the Magmatic System Feeding the Campi Flegrei Volcanic
Field (Italy) Constrained by Radiogenic and Stable Isotope Data”, and
“Tephrochronology and Geochemistry of Tephra from the Campi Flegrei
Volcanic Field, Italy”). The dynamics of the magma chamber is highlighted
throughexperimental(Chap.“RheologicalPropertiesoftheMagmasFeeding
theCampiFlegreiCaldera(Italy)andTheirInfluenceonMixingProcesses”)
and modelling (Chap. “Magma Chamber Dynamics at the Campi Flegrei
Caldera,Italy”)approaches.Thepermanentmonitoringsystemofthevolcano
ispresented(Chap.“ThePermanentMonitoringSystemoftheCampiFlegrei
Caldera, Italy”). The current knowledge on the very active hydrothermal
systemthathasdevelopedwithinthecalderaandplaysanimportantroleinthe
