Stromboli : a natural laboratory of environmental science

Massimo Chiappini a;�, Giovanni P. Gregori b, Gabriele Paparo c,Carlo Bellecci d, Gino M. Crisci e, Giuseppe de Natale f , Paolo Favali a,

Iginio Marson g, Antonio Meloni a, Bruno Zolesi a, Enzo Boschi a

a Istituto Nazionale di Geo¢sica e Vulcanologia (INGV), Vigna Murata 605, Rome, Italyb IFA-CNR, via Fosso del Cavaliere 100, 00133 Rome, Italy

c IDAC-CNR, Rome, Italyd II Universita' di Roma, Tor Vergata, Rome, Italye UNICAL, Arcavacata di Rende, Cosenza, Italy

f Osservatorio INGV Vesuviano, Naples, Italyg OGS, and Universita' di Trieste, Trieste, Italy

Received 4 February 2000; accepted 13 November 2000

Abstract

The science of environment is per se multi- and inter-disciplinary. It is not possible to separate the role of thephysical, chemical, biological, and anthropic factors, respectively. Research must therefore rely on suitable naturallaboratories, where all different effects can be simultaneously monitored and investigated. Stromboli is a volcanicisland slightly North of Sicily, within a tectonic setting characterised by a Benioff zone, curved like a Greek theatre,opened towards the Tyrrhenian Sea, with deep earthquakes. Moreover, it is a unique volcano in the world in thatsince at least V3000 years ago, it has exploded very regularly, about every 15^20 min. Hence, it is possible to monitorstatistically phenomena occurring prior, during, and after every explosion. The Istituto Nazionale di Geofisica eVulcanologia (INGV) has recently established a permanent Laboratory and an extensive interdisciplinary programmeis being planned. A few main classes of items are to be considered including: (1) matter exchange (solid, liquid, gas,chemistry); (2) thermal and/or radiative coupling; (3) electromagnetic coupling; (4) deformation; (5) biosphericimplications; and (6) anthropic relations since either the times of the Neolithic Revolution. Such an entiremultidisciplinary perspective is discussed, being much beyond a mere volcanological concern. We present here thegreat heuristic potential of such a unique facility, much like a natural laboratory devoted to the investigation of theenvironment and climate. < 2002 Elsevier Science B.V. All rights reserved.

Keywords: Stromboli; natural laboratory; environmental science

1. Introduction

At present, the limits of science are biased byan excessive separation into disciplines. In partic-ular, the study of the environment su¡ers fromsuch a drawback, depending on the impossibilityof separating the role of every speci¢c e¡ect inde-

0377-0273 / 02 / $ ^ see front matter < 2002 Elsevier Science B.V. All rights reserved.PII: S 0 3 7 7 - 0 2 7 3 ( 0 1 ) 0 0 2 7 6 - 1

* Corresponding author. Tel. : +39-6-5186-0313;Fax: +39-6-504-1181.

E-mail address: chiappini@ingv.it (M. Chiappini).

VOLGEO 2385 6-5-02

Journal of Volcanology and Geothermal Research 113 (2002) 429^442

www.elsevier.com/locate/jvolgeores

pendent of the other e¡ects. The scope of thepresent paper is the discussion of the heuristicpotential of a natural facility, a dedicated labora-tory, such as the Stromboli island, a unique vol-cano in the world in that it has, for at least thelast three millennia, exploded very regularly,about every 15^20 min. The present paper, how-ever, is not concerned with volcanology, that isonly part of such an entire investigation: withinsuch a complex scenario, every discipline of EarthScience has its own limited and marginal,although relevant, role. It is a presentation ofmultidisciplinary and interdisciplinary ideas,based on extensive discussion and implicit agree-ment between several specialists from di¡erentdisciplines, as a way of conceiving an integratedstrategy for tackling fundamental unsolved gener-al problems. Therefore, short mention must bemade of the origin of such an articulated set ofoften unprecedented and/or sometimes even pro-vocative concepts.

Section 2: Climate, recalls some key aspects ofclimatology. Section 3: Coupling across theEarth’s surface, is concerned with the couplingacross the Earth’s surface, with speci¢c referenceto the surface layers at the boundaries betweensolid Earth, sea/ocean, and atmosphere, whereseveral crucial phenomena controlling environ-ment may occur. Three large sets of phenomenacan be distinguished, i.e. (1) matter exchange(solid, liquid, gas, chemistry) ; (2) thermal and/orradiative coupling; and (3) electromagnetic cou-pling. The last item appears very intriguing, andseems to be crucial for the improvement of ourultimate comprehensive understanding. One re-lated perspective deals with the origin of themagnetic ¢eld of the Earth and with some con-cepts formerly originated from consideration ofthe energy balance of the tidal interaction actingon a realistic Earth model. Section 4: Volcanism,the western Mediterranean, and Stromboli, recallsa few aspects of volcanology, with particularreference to the western Mediterranean basin,and to the speci¢c tectonic setting of Stromboli.Section 5: Natural laboratories and active experi-ments discusses some speci¢c concepts of activemodi¢cation of the environment, and natural fa-cilities used like dedicated multidisciplinary labo-

ratories. Section 6: The Stromboli Laboratory: alist of observations, is a list of the several mon-itoring techniques that in principle are plannedfor application in the Stromboli Laboratory. Sec-tion 7: Conclusion, gives some conclusive re-marks.

2. Climate

The conventional separation of Earth Scienceinto disciplines basically relies on the distinctionbetween solid Earth, oceans (including seas andeventually the entire hydrosphere), atmosphere,biosphere, space, etc. The most di⁄cult items,however, are concerned with their respectiveboundaries, although only a few of them haveas yet been adequately investigated. The magneto-sphere, as the boundary between atmosphere andspace (Kamide, 1988; Jacobs, 1991; Brekke,1997; Gregori, 1998, 1999), and the layer withinthe atmosphere being the boundary between at-mosphere and Earth’s surface, are objects of aconspicuous literature. But, much less concernwas devoted to either one of the ‘surface layers’that are some thin (a few metres) layers either inthe atmosphere, or within soil, or within sea/ocean, where most critical phenomena occurthat ultimately control the entire system. Alsophenomena across the boundary between sea/ocean and their respective £oor have, as yet,been inadequately investigated. For instance, thegreenhouse e¡ect is generally conceived in termsof the gentle cover composed of atmosphericwater (or of other greenhouse atmospheric con-stituents). One can also consider a greenhouse ef-fect in the ionosphere (Kazimirovsky, 2000).

The conventional separation of Earth Scienceinto disciplines should always be considered as atemporary and partial way of approaching under-standing. Every scientist should consider that hisown investigation always has to be focused on itsintegration with other disciplines, with some kindof fusion of the knowledge exploited by di¡erentspecialists. In the opposite case every understand-ing remains in the realm of academic speculationcontributing no ultimate progress of comprehen-sive science.

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442430

3. Coupling across the Earth’s surface

Climate is a phenomenon whose surface layerswithin either the soil, or the sea/ocean, or the at-mosphere are the keys for understanding its ulti-mate processes and mechanisms. Three classes ofinteraction can be considered: (1) gas, liquid, andsolid matter exchange, and chemical coupling; (2)thermal and/or radiative coupling; and (3) elec-tromagnetic coupling.

3.1. Gas, liquid, and solid matter exchange, andchemical coupling

Atmospheric gases are exchanged between at-mosphere and soil, the gas exhalation fromground re£ects either the air formerly penetratedunderground, or the gas released by endogenousprocesses, or the exhalation from buried organicmatter. Such phenomena can be investigated ei-ther by attempting to reproduce, within the labo-ratory, several di¡erent natural environments, orby monitoring the characteristics of air massesafter their crossing over di¡erent kinds of theEarth’s surface (e.g. oceans, deserts, etc.). Themultiannual variation, integrated all over theworld, of gas exhaling from volcanic or geother-mal areas as a key factor for the control of cli-mate has never been monitored. The chemical,isotopic, and mass balance of matter exchangesacross the di¡erent surface layers appears one ofthe main missing gaps in the present understand-ing of environmental science.

3.2. Thermal and/or radiative coupling

Heat transport may occur through: (1) conduc-tion, although in general soil has a very low ther-mal conductivity ; (2) advection by £uids, that in-clude £ux of atmospheric gases underneath theEarth’s surface, water circulation or, wheneverapplicable, also lava; or (3) radiative processes.The prime energy feeding derives from: (1) endog-enous energy; (2) solar radiation; (3) heat trans-ported by advection; or (4) radiative processes.

Several such e¡ects maybe controlled by thebiosphere. For instance, Otterman et al. (1993)observed in the Negev desert a lesser change of

colour of the desert, following the growth of somelichens or fungi or other, apparently capable oftriggering rain precipitation with a statisticallysigni¢cant increase. They claim that such an e¡ectcannot be explained by evapo-transpiration byvegetation, rather in terms of a change of thethermal inertia of soil. Such an intriguing obser-vation envisages that, maybe, a change by somevery minor amount of the thermal regime veryclose to the surface could be capable of triggeringsome microvorticity. This is the ¢rst attempt at aninterpretation. In any case, there is a need formonitoring gas and/or ion/electron exchange be-tween the atmosphere and the soil surface, water£ow underground, underground temperature andelectrical conductivity c vs. depth, water precipi-tation from air on the ground, microvorticity ofair within some very thin surface layer immedi-ately above soil.

There is an endless variety of di¡erent morpho-logical con¢gurations that ought to be speci¢callystudied in order to apply their respective inferencefor the study of climate and environment.

3.3. Electromagnetic coupling

The electromagnetic interaction between theEarth and the solar wind appears to be one ofthe most di⁄cult problems of Earth Science.Even the same origin of the magnetic ¢eld ofthe Earth or of its endogenous energy budget ap-pears extremely di⁄cult. It is customary to claimthat the solar wind cannot a¡ect the Earth’s deepprocesses due to electromagnetic screening by themantle. Such a hypothesis is worthy of furtherinvestigation.

The underground electrical structure is, in gen-eral, quite heterogeneous. Hence, a geo^electro-magnetic phenomenon of any kind, observed onthe occasion of a given earthquake occurringwithin a given area, is hardly expected to be re-peated anywhere else and/or at any other time,even at the same site. We should ¢rst investigatein much greater detail the heterogeneity of deepand shallow earth, prior to attempting or makingany inference about any kind of electromagneticprecursor of earthquakes. In general, the systemhas a very large number of degrees of freedom,

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442 431

and we will never be capable of obtaining ad-equate information about any consistent faction.Every monitored phenomenon only re£ects someerratic and basically random information, whichis physically signi¢cant and indicative only, as faras it is concerned, with the evidence of somechange which is in progress. However, that cannever be strictly expected to give a permanent,reliable, and quantitative monitoring of the stateof the system. One should, therefore, attempt andcarry out monitoring that should be widespreadby using a large array of recording points alongwith a large set of di¡erent techniques. The aim isto get rid of the implicit and unavoidable limita-tion by which no recording can be consideredalone as being reliable and adequately complete.

In conclusion, earthquake precursors probablydo exist, although no strict rule will ever be at-tained relating their respective nature and inten-sity, to their time advance with respect to theshock, and/or to the seismic magnitude. Rather,we should simply feel satis¢ed by detecting thechanging trend of the system, and we shouldjust try to model, as far as possible, the speci¢csystem for the area of concern.

Air^earth currents, spontaneous potentials,geo^electromagnetic behaviour of volcanicplumes, geomagnetic anomalies in volcanic areas,the long-period solar modulation of volcanic ac-tivity and of the deep structure of the Earth, theunexplained correlation between the geomagneticsecular variation and the anomalies of the spinrate of the Earth are observational items, all likelyrelated to each other.

We want to emphasise the fundamental lack ofany adequate understanding of some basic phe-nomena that play a key role in the control ofparameters controlling the evolution of naturaland environmental phenomena.

4. Volcanism, the western Mediterranean, andStromboli

4.1. Items in volcanism

(1) The origin of the energy supply to volcanoesis controversial. Several authoritative volcanolo-

gists claim that the hypothesis of endogenous ra-dioactivity and/or slow phase transformation ap-pears hardly believable. Historically (Gregori andDong, 1996), the most ancient idea consideredwind friction inside underground caverns. Duringthe 18th century, they hypothesised undergroundcombustion of oil. This was later substituted bythe hypothesis of radioactivity and of the slow-phase transformation of fossil energy, since thetime of Earth’s formation. Both on Stromboli’sisland and elsewhere, soil deformation, groundporosity, and gas exhalation either from ‘normal’ground or from fumaroles or both, ought to berelated to the water content within ground, henceto its c, and also to the vegetation cover and to itsvegetative stage. This is a delicate and as yet in-adequately understood problem of the interactionacross soil surface. A comparison of the samekind of recordings collected in tectonically andmorphologically di¡erent areas ought to givesome relevant indication for a more concreteunderstanding of the ultimate processes that con-trol climate, seismic and volcanic phenomena.From such a viewpoint, Stromboli needs to bemonitored for several years prior to exploitingits entire heuristic potential.

(2) Every volcano is a case history on its own,and no general rule can be given. Volcanism isoriginated by an excess endogenous heating(whatever its origin may be) that causes an in-crease in pressure that must be released. Such aprocess occurs ¢rst of all through water, gas, etc.that have great mobility and can transport heatby advection. Heat must accumulate and pressureincrease. Whenever the lithostatic pressure is ad-equately low, a new £uid, i.e. lava, is eventuallyformed acting much like all other £uids. Such alava liquefaction process is similar to what hap-pens in a blast furnace. Under other circumstan-ces, when the heat and pressure increase occurs atsome comparatively greater depth, no lava can beformed due to the constraints by equation-of-state, and the volcano warms up much like eithera pressure cooker or the boiler of a steam engine.Di¡erently stated, in such a case, pressure in-creases faster than temperature, while the equa-tion-of-state forbids liquefaction. Finally, the vol-cano will eventually explode. Therefore, every

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442432

speculation about the ‘magma chamber’ of a vol-cano can sometimes be misleading. It is oftenspeculated that a magma chamber is a reservoirthat always exists, and that either originates as alava emplacement, or in any case it is the primeheat source for a phreatic explosion. In contrast,a heat source always exists, but there appears tobe no sound reason by which it should be alwaysassociated with a real magma chamber. For in-stance, a few years ago, the crisis of the PhlegreanFields displayed an upheaval of a large area byalmost 2 m in 1 yr. The most convincing explan-ation of such in£ation and subsequent de£ationwas in terms of a hydrothermal, rather than amagmatic, process. A related item deals with thespeculated magma chamber of mid-ocean ridges(¢rst discussed by (Gregori and Lanzerotti,1982), that a few years later could not be foundby standard ocean bottom geo^electromagneticsounding, magnetotellurics (MT) and other (Con-stable, 1990 and references therein), either bysearching for an electromagnetic coupling with atransoceanic communication cable (Meloni et al.,1984), or by means of the polarisation of the per-turbations recorded within the network of geo-magnetic observatories (Gregori et al., 1987).

(3) An important drawback of present volca-nology is the lack of monitoring of submarinevolcanism (Simkin and Siebert, 1994), notwith-standing the geologic time scale, in terms of outp-oured volume, it appears that it is responsible forV3/4 of global volcanism. Such routine monitor-ing could be achieved either by recording the as-sociated minor seismic activity by means of someunrealistic and very dense network of sea-bottomseismometers. Otherwise, the currents inducedinto the network of the commercial submarinecommunication cables could provide (Meloni etal., 1983; Lanzerotti and Gregori, 1986), aftersuitable calibration, e¡ective real-time and high-time resolution monitoring, although restricted toseveral spatial bands all over the Earth’s surface,and with a limited spatial resolution.

(4) Chemical geodynamics (e.g. Wilson, 1989)was started and de¢ned only a few decades ago.A successful classi¢cation of ocean £oor basaltwas attained by considering the isotope concen-tration ratios 206Pb/204Pb, 207Pb/204Pb, 208Pb/

204Pb, 87Sr/86Sr, and 143Nd/144Nd, plus a fewothers for which, however, some comparativelymore limited and as yet inadequate data set isavailable. This was interpreted by speculating ondi¡erent reservoirs that ought to exist, by di¡erentextension and possibly at di¡erent depths, in dif-ferent regions. All observations ought thus to bethe consequence of the output of primary compo-nents originated from such reservoirs, and by sub-sequent basalt contamination, while they cross thecrust. An alternative interpretation may considerrather the space-varying prime heat intensity, bywhich the melting of the basalt occurs at a di¡er-ent depth depending on the intensity of such aprime heat supply. Hence, the outpouring basaltsamples the isotopic chemistry of a layer at adi¡erent depth in di¡erent areas. In this way,the prime heat intensity, chemical geodynamics,magma £uidity, and hence the island topographicheight (or equivalently the bathymetry of a sea-mount) do, in fact, depend on each other accord-ing to some apparently regular and simple law.

(5) Volcanism may control climate and environ-ment. A great concern deals is the impact of cata-strophic explosions (e.g. Pinatubo, Unzen, etc.) byanalogy to nuclear winters, etc. (Rampino et al.,1988; Pittock et al., 1988; Harwell and Hutchin-son, 1988). The problem, however, is very com-plex.

4.2. The west Mediterranean volcanism

Tectonics of the Mediterranean basin is verycomplex (Mantovani, 1997; Mantovani and Al-barello, 1997; Mantovani et al., 1997a,b,c; Vitiet al., 1997, and references therein). The portionof peninsular Italy west of the Apennines displaysrelevant geothermal and volcanic features. TheTyrrhenian Sea £oor has the character of anocean (Fig. 1), with a great number of seamounts(and corresponding magnetic anomalies), volca-noes active during the last few million years andelevating from an abyssal plain down to a depthof V4000 m. Sicily is part of the African plateand it pushes against peninsular Italy, being thelikely cause of the Italian seismicity. The Sicilychannel (or Pantelleria graben) is shallow (a fewhundred metres deep), and includes the volcanic

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442 433

Fig. 1. Magnetic anomalies of the Italian region. Notice the conspicuous anomalies on the bottom of the Tyrrhenian Sea, themost of which are associated with volcanic seamounts. After Chiappini et al. (2000).

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442434

islands of Pantelleria (EsperancPa and Crisci,1995), and Linosa. Another island, named Ferdi-nandea (by the Sicilian government of that time),or Graham (by the British £eet), or Julie (by theFrench geologist Constant Pre¤vost), was born on13 July 1831, but it soon eroded, until itdisappeared on 28 December 1831. At that time,it was the object of considerable internationalcontroversy, due to its strategic location. AV2000-m-deep escarpment is located on the pro-longation towards Africa of the eastern Siciliancoast.

Vesuvius and Etna are comparatively close toeach other, and are probably the best historicallydocumented volcanoes of the world, having, how-ever, a completely di¡erent character. Vesuviushas often been explosive, with varying cycles ofthe order of almost V7 centuries’ duration. Everysuch long cycle begins by three periods of appar-ent repose, followed by a ‘spectacular’ periodcharacterised by e¡usive eruptions alone. At theend of every ¢rst and third such ‘repose’ period, itexperienced a sub-Plinian explosive eruption (i.e.producing more than 0.1 km3 of ejecta).

The origin of the energy supply for either Ve-suvius or Etna is still unknown. The MessinaStrait was carefully monitored and shown tohave a fairly constant width. Upon considerationof the aforementioned pressure by Sicily againstthe Italian peninsula, some highly e⁄cient pivotor gear should be located within such an area,originating from some conspicuous local frictionthat must be released, thus possibly explainingEtna’s, although not Vesuvius’ character.

Another most relevant volcanic feature is thePhlegrean Fields slightly NW of Naples (Rosiand Sbrana, 1987). They are a nested caldera re-sulting from the collapses of the so-called Campa-nian Ignimbrite (36 kyr BP) and Neapolitan Yel-low Tu¡ (12 kyr BP). They have been the site ofboth widespread volcanism and block resurgence.The younger volcanism occurred in two periodsbetween 10 and 8 and 4.5 and 3.7 kyr BP. Onefamous episode occurred in 1538 AD from whicha new mountain originated, the Monte Nuovo.Moreover, between 1969 and 1972, great concernwas caused by an uplift of V1.7 m, with a peakrate of 0.02 mm day31 (de Natale, 1995). Since

December 1984, subsidence occurred, and be-tween the end of 1988 and April 1989, a minorepisode of uplift (maximum 7.5 cm) was observed(Civetta et al., 1995).

The Aeolian archipelago slightly North of Sicilyis composed of several islands renowned sinceclassic antiquity. This area is particularly intrigu-ing from the archaeological point of view. It was,in fact, crucial for investigating the former occu-pation of the Mediterranean region by mankind,either at the time of the Neolithic Revolution orafter the deserti¢cation of the Sahara. This eventcompelled its former inhabitants to emigrate, giv-ing rise to the Basques, the Etruscans, the Mino-ans (Arna'iz Villena and Garc|'a, 1998). From sucha perspective, it appears to be a still unexploitedimportant archaeological resource. The ancientGreeks knew about active volcanoes only occur-ring in western Mediterranean, and knew aboutthe existence of huge caverns underground.Hence, it appeared reasonable to correlate cav-erns, winds, air friction underground, and volcan-ism (Gregori and Dong, 1996). The entire mor-phology of the Aeolian archipelago recalls anisland arc, which, in fact, it is named in thisway. But, its basalt isotopic signature recallsocean £oors, rather than island arcs. Crisci et al.(1991) and EsperancPa et al. (1992) proved thetime variation, on the geologic time scale, of itsbasalt isotopic chemistry. This aspect seems tohave never been focused in any other volcanicisland. A few more recent isotope ratio measure-ments for the Vulcano island are reported by Pi-narelli et al. (1995).

The island of Vulcano had an exceptionallygreat activity documented by geologic evidenceduring V1250^550 BC, and historically reportederuptions during the 5th century BC (Gregori,1997). In the late 1980s, and early 1990s, someserious concern arose about such an island (Bau-bron et al., 1990, 1991; Italiano et al., 1998) dueto a signi¢cant large increase of gas exhalationobserved from ground, being a possible precursorof a restarting activity. The phenomenon laterfaded o¡. Frazzetta and La Volpe (1991) studiedits history, morphology and cycles, while concern-ing a 6th century eruption, see Gioncada et al.(1995) and references therein.

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442 435

4.3. Stromboli

The Stromboli Island is a unique volcano of theworld in that about every 15^20 min it has anexplosion (typically called ‘Strombolian type’),and it is possible to monitor its entire systemand to investigate the processes that precede, pre-pare, develop, and ¢nally exploit every such ex-plosion. Every explosion is the start of the stop-watch for a new experiment. Di¡erent explosionsare never exactly the same. There is a unique andgreat heuristic potential related to the possibilityof investigating phenomena with large statistics.The radiochronological dating of its ejecta duringthe last V100 000 yr was given by Gillot andKeller (1993).

The energy supply to Stromboli is of some con-cern. Upon a formal estimate (Giberti et al., 1992)it appears that, if the origin is some continuousheat-re¢ll by a steady lava £ow (operated muchlike a cooling circuit that warms water and trig-gers volcanic explosions), one should expect a£ow of V200 kg s31. It seems hard to believethat such an impressive regularity persisted forseveral millennia.

On the other hand, suppose that the explana-tion is in terms of a subduction mechanism, oc-curring within such an unusual and peculiar ‘is-land arc’ (provided that it can be likened to atypical island arc of the Paci¢c and/or Atlanticoceans). In such a case, such a mechanism oughtto be capable of explaining its explosive V15^20min regularity, compared to the several centuriesactivity of its close islands in the same archipela-go. Moreover, whatever the origin is, is the supplyof Stromboli via either friction, or Joule heating,or something else? Chemical geodynamics canprovide, perhaps, some hunches concerning theanalogies and/or di¡erences between the Aeolianarchipelago and a standard island arc.

5. Natural laboratories and active experiments

The concept of a natural laboratory, opposedto the concept of a standard indoor laboratory, isconcerned with every case history in which eithera given system is ‘almost’ isolated with respect to

the other systems, or some phenomena can beobserved under di¡erent conditions

For instance, Stromboli is a system that is wellde¢ned and substantially ‘isolated’ with respect toother emerged lands, and it allows the use of largestatistics in that its regular and frequent activityenable the same experiment to be repeated asmany times as is necessary under slightly di¡erentconditions. Hence, it is a unique facility for carry-ing out a feasible observational programme forinvestigating several mechanisms. The same argu-ment can be applied to every island, sea/oceanbasin, lake, valley, or catchment area of everygiven river system, etc.

The second aforementioned occurrence of a‘natural laboratory’ can be better explained interms of the following two examples, where the‘natural laboratory’ is the ensemble of severalsites altogether as follows.

The investigation, e.g. by means of optical tech-niques of the quality of air masses after theircrossing over large extensions of a speci¢c surface(e.g. steppe, prairie, ocean, desert, permafrost, ice,etc.), can be accomplished by means of routineobservations from a network of high-altitude at-mospheric observatories. This is one examplewhere the ensemble of all such observatories isthe natural laboratory, while any kind of evengreatly sophisticated recordings collected at oneobservatory alone could hardly provide any infor-mation comparable with the multi-observatorycomparison.

The other example is concerned with the re-cordings of acoustic emissions (AE) monitored,e.g. at 200 kHz, in di¡erent environments. Fig.2 shows recordings on Gran Sasso, the highestmountain of the Apennines in central Italy thatis mainly composed of dolomite, marl, and lime-stone. The two curves show the output of trans-ducers for AE at 200 kHz inside rock and air,respectively. The transducer is located on a steelrod entering into ground for V12 m. The signaloriginates within ground, as a consequence of thedaily thermal and/or tidal soil deformation. Thethermal e¡ect occurs only within some shallowlayer (several tens of centimetres), while the tidaldeformation a¡ects the entire mountain. The dif-ference between curves A and B shows that the

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442436

e¡ect has no perturbation of external origin. Foradditional con¢rmation, the natural electric ¢eldwas measured by using the same metal rod in-serted into soil, and operated as a receiving anten-na tuned on the same frequency 200 kHz. Such anatural electric ¢eld is well known to originate bynatural sources (ionosphere and its correspondinginduced telluric currents underground), and itshows the expected large diurnal variation beingmaximum during day time. The likely interpreta-tion is that the AE signal shows a maximum dur-ing night-time, when soil contracts and cools o¡.

AE recordings were collected on the Stromboliisland. A several month (discontinuous) data set isavailable, and extensive analysis is in progress. Ingeneral, an invariant law is that an AE burst isobserved a few minutes prior to every explosion(Diodati, 1994).

AE recordings at low (25 kHz) and high (160kHz) frequency are being collected on Vesuvius ata site located a few hundred metres from the rimof the crater. The transducer is put on top of aglass rod inserted for V50 cm into a lava dike.Glass ensures the absence of electromagnetic per-turbations. The noise is V0.2 mV, there is a di-

urnal modulation of amplitude V1 mV, and AEbursts are observed with a varying observed am-plitude ranging between V10 mV and V2 V.One example is shown in Fig. 3. The present pre-liminary inference shows ¢rst a burst at 160 kHz,that seems to be later followed by a burst at 25kHz.

Summarising, every such system can be consid-ered as a part of a true natural laboratory, in thefact that we know that nature shows us somephenomena that appear likely to originate bysome speci¢c mechanism. Moreover, we can re-peat the same experiment in di¡erent environmen-tal settings, much like in the case we operate in-side a standard laboratory in order to assess therelevant natural laws governing the phenomenon.It ought to be emphasised that operating the sameexperiment in di¡erent natural settings, is muchdi¡erent compared to carrying out a multidiscipli-nary investigation, always on the same system.

Another item related to Stromboli deals withthe concept of active experiment. When dealingwith a standard laboratory experiment, the re-searcher usually changes the boundary conditionsof every experiment in order to assess the laws

Fig. 2. Recordings in the area of the Gran Sasso in central Italy, during May 29 through June 6, 1996. It shows the output ofAE transducers at 200 kHz both inside rock and in air, and the natural electric ¢eld recorded by using a metal rod inserted intoground for V12 m and used as a receiving antenna tuned on the same frequency. The AE appear to be much larger during thedaily cooling of soil occurring during local nighttime.

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442 437

that govern it. Research in the environment ratherimplies, in general, only passive observation withno possibility of modifying the system. Such aproperty, however, has some exceptions, as re-ported in the following. Some planetary-scale ex-periments of active modi¢cation of the Earth’sionosphere and/or magnetosphere were concernedwith high-altitude nuclear tests (McNoe, 1996).The weekend e¡ect associated with the operationof the BART train in the San Francisco area(Fraser-Smith and Coates, 1978; Fraser-Smith,1981) is another example, as well as the electric¢eld measurements by Haerendel’s classical Bareleases (see e.g. Kamide, 1988; Jacobs, 1991;Brekke, 1997). A few years ago, an entire set ofactive experiments dealing with plasma in spacewas concerned with the use of the Tethered Sat-ellite System (TSS) operated with a conductingtether. E¡ects associated with the anthropic ac-tion can produce an active modi¢cation of theenvironment. Typical examples are e.g. the eu-trophisation of a lake or of a river, with conse-quences on the greenhouse e¡ect, the increasinginjection into the environment of warm water(Ellsaesser et al., 1986), or even the impact of

CFC on the ozone layer or of atmospheric CO2

on global warming.In this respect, Stromboli appears particularly

stimulating, in the fact that it is possible to startthe stopwatch at the time of every explosion, andto monitor all that happens either before, or dur-ing, or after it. Every explosion is thus one activemodi¢cation, by which a given measured amountof matter and of energy is injected into the envi-ronment. We can monitor, investigate, study itsbehaviour, di¡usion, decay, recovery, etc. underever-changing conditions, with the possibility ofexploiting large statistics. Considering the greatamount of uncertainty dealing with the funda-mental laws, processes, and mechanisms that con-trol and determine climate, and the great presentenvironmental hazard, threaten, and concern,such a possibility de¢nitely appears to be of para-mount relevance.

6. The Stromboli Laboratory: a list ofobservations

A permanent laboratory has recently been es-

Fig. 3. Recordings in the area of Vesuvius. Several AE at 25 and 160 kHz are shown. Every row datum is the sum of all peaksof all bursts occurring during a total time lag of V5 ms.

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442438

tablished on Stromboli by INGV, and an ex-tensive interdisciplinary programme is beingplanned. Let us recall the possibility of carryingout some analogous measurement also on the oc-casion of an eventual eruption of Etna, whichcould occur sometimes while operating theStromboli experiment. This could allow forsome interesting comparison, when consideringthe possible di¡erent prime energy supply of thetwo volcanoes.

Concerning Stromboli, several classes of prob-lems are envisaged: (1) matter exchanges (chem-ical and isotopic aspects, including chemical geo-dynamics) ; (2) thermal and/or radiative coupling;(3) electromagnetic coupling, including magneticand electric properties of the volcano; (4) defor-mation; (5) biospheric interactions; and (6)anthropic relations (i.e. archaeology since Palaeo-lithic times). The last item appears interestingconsidering the particular geographical locationof the entire Aeolian archipelago for a strategyfor the investigation of the former occupation ofthe Mediterranean area either at the time of theNeolithic Revolution or such a process was, per-haps, also correlated with the volcanic activity vs.time of the di¡erent Aeolian Islands. Also in thisrespect, the Stromboli Laboratory appears to be astimulating opportunity for promoting an opera-tive interaction between specialists of exact scien-ces and of humanistic disciplines, with the pur-pose of studying the anthropology of therelations between man and environment (Gregoriand Gregori, 1998).

A few aspects appear worthy of special men-tion, as such experiments can be carried outonly at Stromboli. Measuring the average speed,the total mass, and the total electric charge of theejecta of every explosion; studying the lightningphenomena in volcanic plumes; searching for pos-sible lesser transient disturbances in the iono-sphere associated with every explosion are all ac-tivities which can be carried out in the laboratory.Other aspects are self-explanatory in the followinglist. Their interpretation has to be carried out byconsidering that the prime agents are: (1) endog-enous thermal heat; (2) tidal deformation of soil ;(3) meteorological factors ; and (4) biological con-trol.

The monitored phenomena being presently en-visaged are:

b The chemical and isotopic composition, andrelative temporal evolution, of the Aeolian vol-canism during geologic past

b Mineralogical, geochemical, and isotopic data(soil, water, air)

b Aerogeophysics (high resolution, multilevelrepeated measurements)

b Sea £oor monitoring (GEOSTAR) (Beranzoliet al., 1998)

b Gravimetryb Tilt, stress, strain (at surface, and within a

V50-m bore-hole)b Temporal variation of bathymetry (high sen-

sitivity)b Soil deformationb Seismicity and tomographyb Microseismicity and acoustic emissionb A ring of buoys for monitoring acoustic emis-

sions and temperatureb Geothermics (shallow and deep)b Thermal pro¢le within shallow soil (6 3.5 m

depth), i.e. ‘geotherms’b Chemistry and gases associated with water

wellsb Fumarolic activity (both on land and under

sea)b Gas exhaled from soilb Total balance of gas exhalation and ex-

changes (thermal, radiative, chemical, solid, liq-uid) between soil, sea, and atmosphere, includingsubmarine fumaroles

b Tracking the underground bubble formationand its propagation, prior to its explosion into theatmosphere

b Local meteorological and environmental im-pact (including standard meteorological record-ings, radiative balance, tethered balloon, and nu-merical micro-meteorological modelling)

b Boundary layer meteorology either with orwithout volcanic injection

b Gas entering from the atmosphere into soilb Atmospheric electrical conductivityb Atmospheric electrical potential gradientb Atmospheric microvorticity very close to

ground surface (e.g. by monitoring the twinklingof light and the atmospheric optical depth)

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442 439

b The total amount, the average speed, and thechemistry, of the ejecta of every explosion and ofits exhaled gases and aerosols, by means of eitherSODAR, or LIDAR, or aureolametry

b Non-parametric characterisation of biotaboth underground and on the soil surface, andof their vegetative stage

b Water content within soil vs. both depth andtime

b Electrical conductivity c of soil vs. bothdepth and time

b Time variation of soil porosity by monitoringmicrodeformation in terms of: (1) acoustic emis-sion; and (2) high-sensitivity tiltmetry

b Spontaneous potentials and geoelectricsb Geomagnetic ¢eld (variation, and absolute),

and telluric currentsb Geo^electromagnetic tomographyb Lightning discharges (strikes and strokes,

both within the plume and independent of it)b Ionospheric transients (recorded from the Gi-

bilmanna ionospheric observatory, permanentlyoperated by INGV on the northern coast of Si-cily).

7. Conclusion

The science of the environment cannot be rec-onciled with the standard separation into disci-plines and their further splitting into specialities.There is a strict need for substantial and wideteamwork, a perspective that is di⁄cult consider-ing the instinctive tendency of scientists to isolatethemselves within their own cultural concern.Moreover, it appears very di⁄cult to envisageconcrete experimental con¢gurations where spe-cialists from di¡erent branches of knowledge doe¡ectively and practically co-operate with a com-mon target in mind. Stromboli, with its incrediblemillennial regularity, with its isolation with re-spect to all other emerged lands, with the compa-ratively simple feasibility of an integrated multi-disciplinary monitoring project, o¡ers someopportunities that could hardly be met in everyother site all over the world. With this perspectivein mind, the Stromboli Laboratory installed andoperated by ING is likely to be a great opportu-

nity for the international scienti¢c community forexploiting some unprecedented and substantialprogress in the understanding of the mechanismsthat challenge and threaten our environment.

Acknowledgements

It is not possible to do justice to all the inputs byfriends, colleagues, and authoritative scientistsover the last few years of talks, meetings, work-shops, private discussions, etc. We want to stressour sincere appreciation and gratitude, in geogra-phical order, to Prof. M. Riuscetti and co-workersfrom the University of Udine; to Prof. A. Vettorefrom the University of Padova ; to Prof. J.Chahoud from the University of Bologna; to Dr.G. Martinelli of the Servizio Geografico e Geolo-gico della Regione Emilia-Romagna (Bologna); toProf. S. Lombardi and co-workers from theUniversity La Sapienza (Rome), to Dr. V. Iafollafrom IFSI (CNR, Rome); and to several collea-gues of INGV, and of CNR (IDAC, IFA, IAS,IFSI, IRTR) in Rome and IMAAA in Potenza.We are indebted with Prof. Paolo Diodati from theUniversity of Perugia and Dr. Paolo Palangiofrom INGV for providing Fig. 2, and with Prof. E.Mantovani from the University of Siena for thereferences on the geodynamics of the Mediterra-nean area. Concerning the archaeological items,we want to thank Arch. G. Campo and Arch. A.Rotella of the Soprintendenza ai Beni Culturali edAmbientali (Messina), and Dr. Neda Parmegianiand Dr. Lucia Vagnetti from the Istituto di StudiMicenei ed Egeo-Anatolici (CNR, Rome). Finally,we are glad to acknowledge the several invited andcontributed talks and the discussions during thetwo national Italian workshops devoted to Strom-boli, held in Rome on 9 March, 1998, and on 29^30 October, 1998, respectively. The internationalworkshop’s observational data base and mechan-isms of climate held at Erice (Trapani) onNovember 21^27, 1998 and the Bridge betweenthe Big Bang and Biology (Stars, Planetarysystems, Atmospheres, Volcanoes : Their Linkto Life), held at Stromboli on September 13^17,1999, provided important inputs for the presentpaper.

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442440

References

Arna'iz Villena, A., Garc|'a, J.A., 1998. El Origen de los Vascosy Otros Pueblos Mediterra'neos. Estudios Complutenses, Ed-itorial Complutense, Madrid, 139 pp.

Baubron, J.C., Allard, P., Toutain, J.P., 1990. Di¡use volcanicemissions of carbon dioxide from Volcano Island, Italy. Na-ture 344, 51^53.

Baubron, J.C., Allard, P., Toutain, J.P., 1991. Gas hazard onVulcano Island. Nature 350, 26^27.

Beranzoli, L., Favali, P., Etiope, G., Frugoni, F., Smriglio, G.,Gasparoni, F., Marigo, A., 1998. GEOSTAR geophysicaland oceanographic station for abyssal research. Phys. EarthPlanet. Inter. 108, 175^183.

Brekke, A., 1997. Physics of the Upper Atmosphere. JohnWiley and Sons and Praxis, Chichester, 491 pp.

Chiappini, M., Meloni, A., Boschi, E., Faggioni, O., Beverini,N., Carmisciano, C., Marson, I., 2000. Shaded relief mag-netic anomaly map of Italy and surrounding marine areas.Ann. Geo¢s., 43, 983^989.

Civetta, L., del Gaudio, C., de Vita, S., di Vito, M., Orsi, G.,Petrazzuoli, S., Ricciardi, G., Ricco, C., 1995. Volcanismand resurgence in the densely populated Campi Flegreinested caldera. Period. Mineral. 64, 135^136.

Constable, S.C., 1990. Marine electromagnetic induction stud-ies. Surv. Geophys. 11, 303^327.

Crisci, G.M., de Rosa, R., EsperancPa, S., Mazzuoli, R., Son-nino, M., 1991. Temporal evolution of a three componentsystem: the island of Lipari (Aeolian arc, southern Italy).Bull. Volcanol. 53, 207^221.

de Natale, G., 1995. Mechanisms of unrest episodes al CampiFlegrei Caldera. Period. Mineral. 64, 163^163.

Diodati, P., 1994. Ultrasonic signals before, during and afterseismic activity revealed on Stromboli. Acoust. Lett. 17,233^237.

Ellsaesser, H.W., MacCracken, M.C., Walton, J.J., Grotch,S.L., 1986. Global climatic trends as revealed by the re-corded data. Rev. Geophys. Space Phys. 24, 745^792.

EsperancPa, S., Crisci, G.M., de Rosa, R., Mazzuoli, R., 1992.The role of the crust in the magmatic evolution of the islandof Lipari (Aeolian islands Italy). Contrib. Mineral. Petrol.112, 450^462.

EsperancPa, S., Crisci, G.M., 1995. The Island of Pantelleria: acase for the development of DMM-HIMU isotopic compo-sition in a long-lived extensional setting. Earth Planet. Sci.Lett. 136, 167^182.

Fraser-Smith, A.C., 1981. E¡ects of man on geomagnetic ac-tivity and pulsations. Adv. Space Res. 1, 455^466.

Fraser-Smith, A.C., Coates, D.B., 1978. Large-amplitude ULFelectromagnetic ¢elds from BART. Radio Sci. 13, 661^668.

Frazzetta, G., La Volpe, L., 1991. Volcanic history and max-imum expected eruption at ‘La Fossa di Vulcano’ (AeolianIslands, Italy). Acta Vulcanol. 1, 107^113.

Giberti, G., Jaupart, C., Sartoris, G., 1992. Bull. Volcanol. 54,535^541.

Gillot, P.-Y., Keller, J., 1993. Radiochronological dating ofStromboli. Acta Vulcanol. 3, 69^77.

Gioncada, A., Gurioli, L., Sbrana, A., 1995. The hydrothermalmagmatic eruption of ‘Breccia di Commenda’. La Fossa diVulcano, Eolian Islands, Italy. Period. Mineral. 64, 191^192.

Gregori, G.P., 1998. The magnetosphere of the Earth. Atheory of magnetospheric substorms and of geomagneticstorms. In: Schro«der, W. (Ed.), From Newton to Einstein.Festschrift in honour of the 70th birthday of Hans-JuergenTreder. Science Edition, Bremen, pp. 68^106.

Gregori, G.P., 1999. The external magnetic sources over thepolar caps. Feasible modelling vs. unrealistic expectations.Ann. Geo¢s. 42, 171^189.

Gregori, G.P., Lanzerotti, L.J., 1982. Electrical conductivitystructure in the lower crust. Geophys. Surv. 4, 467^499.

Gregori, G.P., Dong, W., 1996. The prime mover of volcanoes.History of a concept (in the ‘western’ science). In: Schro«der,W., Colacino, M. (Eds.), Global Change and History ofGeophysics. IDCH of IAGA, Bremen, pp. 12^75.

Gregori, G.P., Gregori, L.G., 1998. Solar^terrestrial relations.A reminder. Acta Geod. Geophys. Hung. 33, 391^459.

Gregori, G.P., Lanzerotti, L.J., Alessandrini, B., de France-schi, G., Cipollone, R., 1987. The planetary scale distribu-tion of telluric currents and the e¡ect of the equatorial elec-trojet: an investigation by Canonical GDS. Pure Appl.Geophys. 125, 369^392.

Gregori, L.G., 1997. The myth of Hephaestus and the activityof the island of Vulcano. In: Schro«der, W., Geomagnetismand Aeronomy with Special Case Studies. Science Edition,Bremen, pp. 295^314.

Harwell, M.A., Hutchinson, T.C., 1988. Environmental Con-sequences of Nuclear War. 2nd ed., Vol. II, Ecological andAgricultural E¡ects. SCOPE 28, ICSU, and John Wiley andSons, Chichester, 523 pp.

Italiano, F., Nuccio, M., Pecoraino, G., 1998. Steam outputfrom fumaroles of an active volcano: tectonic and magmatichydrothermal controls on the degassing system at Vulcano(Aeolian arc). J. Geophys. Res. 103, 29829^29841.

Jacobs, J.A. (Ed.), 1991. Geomagnetism, Vol. 4. AcademicPress, Harcourt Brace Jovanovich, London, 806 pp.

Kamide, Y., 1988. Electrodynamic Processes in the Earth’sIonosphere and Magnetosphere. Kyoto Sangyo UniversityPress, Kyoto, 756 pp.

Kazimirovsky, E.S., 2002. Coupling between troposphere, stra-tosphere, thermosphere and lower ionosphere. In: Gregori,Piervitali, in press.

Lanzerotti, L.J., Gregori, G.P., 1986. Telluric Currents: TheNatural Environment and Interactions with Man-Made Sys-tems. In: Kride, E.P., Roble, R.G. (Eds.), The Earth’s Elec-trical Environment. National Academic Press, WashingtonD.C., pp. 232^257.

Mantovani, E. (Ed.), 1997. Geodynamics of the Mediterraneanregion and its implications for seismic and volcanic risk.Ann. Geo¢s. 40, 569^781.

Mantovani, E., Albarello, D., 1997. Middle term precursors ofstrong earthquakes in southern Italy. Phys. Earth Planet.Inter. 101, 49^60.

Mantovani, E., Albarello, D., Tamburelli, C., Babbucci, D.,1997. Recognizing the Italian zones most prone to next large

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442 441

earthquakes: possible approaches and present chances. Ann.Geo¢s. 40, 1329^1344.

Mantovani, E., Albarello, D., Tamburelli, C., Babbucci, D.,Viti, M., 1997. Plate convergence, crustal delamination, ex-trusion tectonics and minimization of shortening work asmain controlling factors of the recent Mediterranean defor-mation pattern. Ann. Geo¢s. 40, 611^643.

Mantovani, E., Albarello, D., Babbucci, D., Tamburelli, C.,1997. Recent/present tectonic processes in the Italian regionand their relation with seismic and volcanic activity. Ann.Tecton. 11, 27^57.

McNoe, P.A., 1996. Auroral and magnetic e¡ects of high alti-tude nuclear explosions in the magnetically conjugate regionnear western Samoa. In: Schro«der, W., Colacino, M. (Eds.),Global Change and History of Geophysics, IDCH of IAGA,Bremen, pp. 161^172.

Meloni, A., Lanzerotti, L.J., Gregori, G.P., 1983. Induction ofcurrents in long submarine cables by natural phenomena.Rev. Geophys. Space Phys. 21, 795^803.

Meloni, A., Gregori, G.P., Lanzerotti, L.J., Medford, L.V.,1984. Search for a possible electromagnetic coupling be-tween a transatlantic communication cable and the magmachamber in the mid-Atlantic ridge. J. Geophys. 55, 185^190.

Otterman, J., Novak, M.D., Starr, D.O’C., 1993. Turbulentheat transfer from a sparsely vegetated surface: two-compo-nent representation. Bound. Layer Meteorol. 64, 409^420.

Pinarelli, L., del Moro, A., Gioncada, A., Sbrana, A., 1995. Sr,Nd, and Pb isotope characterization of Vulcano Island(Aeolian Arc Italy). Period. Mineral. 64, 249^250.

Pittock, A.B., Ackermann, T.P., Crutzen, P.J., MacCraken,M.C., Shapiro, C.S., Turco, R.P. 1988. Environmental Con-sequences of Nuclear War. 2nd ed., Vol. I, Physical andAtmospheric E¡ects. SCOPE 28, ICSU, and John Wileyand Sons, Chichester, 359 pp.

Rampino, M.R., Self, S., Stothers, R.B., 1988. Volcanic win-ters. Annu. Rev. Earth Planet. Sci. 16, 73^99.

Rosi, M., Sbrana, A. (Eds.), 1987. Phlegrean Fields. Quad.Ric. Sci., (114), (Progetto Finalizzato ‘Geodinamica’, Mono-gra¢e ¢nali Vol. 9), CNR, Rome, 168 pp.

Simkin, T., Siebert, L., 1994. Volcanoes of the World, 2nd edn.Geoscience Press, Tucson, AZ, 349 pp.

Viti, M., Albarello, D., Mantovani, E., 1997. Rheological pro-¢les in the central^eastern Mediterranean. Ann. Geo¢s. 40,849^864.

Wilson, M., 1989. Igneous Petrogenesis. A Global TectonicApproach. Unwin Hyman, London, 466 pp.

VOLGEO 2385 6-5-02

M. Chiappini et al. / Journal of Volcanology and Geothermal Research 113 (2002) 429^442442