Journal of Volcanology and Geothermal Research 311 (2016) 79–98

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Journal of Volcanology and Geothermal Research

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Active tectonic features and structural dynamics of the summit area ofMt. Etna (Italy) revealed by soil CO2 and soil temperature surveying

Salvatore Giammanco a,⁎, Gladys Melián b,c, Marco Neri a, Pedro A. Hernández b,c, Francesco Sortino d,José Barrancos b,c, Manuela López a, Giovannella Pecoraino d, Nemesio M. Perez b,c

a Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Sezione di Catania, Italyb Environmental Research Division, Instituto Tecnológico y de Energías Renovables (ITER), Spainc Instituto Volcanológico de Canarias (INVOLCAN), Spaind Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Italy

⁎ Corresponding author at: Piazza Roma 2, 95123, CatanE-mail address: salvatore.giammanco@ingv.it (S. Giam

http://dx.doi.org/10.1016/j.jvolgeores.2016.01.0040377-0273/© 2016 Elsevier B.V. All rights reserved.

a b s t r a c t

a r t i c l e i n f o

Article history:Received 23 July 2015Accepted 8 January 2016Available online 16 January 2016

This work presents the results of an extensive geochemical survey aimed at measuring soil CO2 effluxes and soiltemperatures over a large portion of Mt. Etna's summit area, coupled with an updated structural survey of thesame area. The main goals of this study were i) to find concealed or hidden volcano-tectonic structures in thestudied area by detecting anomalous soil gas emissions, ii) to investigate the origin of the emitted gas and themechanism of gas and heat transport to the surface, iii) to produce a structural model based both on the surfacegeology and on the soil gas data and, lastly, iv) to contribute to the assessment of hazard from slope failure andcrater collapses at Mt. Etna. The results revealed many concealed structural lines that followed the major direc-tions of structural weakness in the summit area of Mt. Etna, mostly due to a combined action of gravitationalspreading of the volcano and magma intrusions. Both recent and old volcano-tectonic lines were found to actas pathways for the leakage of magmatic gases to the surface. An important role in driving magmatic gases tothe surface is also played by fracturing and faulting due to caldera-forming collapses and smaller crater collapses.Correlation between soil CO2 emissions and soil temperature allowed discriminating areas of active shallow hy-drothermal circulation along deep fractures (characterized by high values of both parameters, but mostly soiltemperature) from those affected by undeveloped fractures that did not reach the surface (characterized byhigh CO2 emissions at low temperature). The former corresponded to weak zones of the volcano edifice thatwere frequently site of past eruptions, indicating that those areas keep a high potential for future opening oferuptive fissures. The latter were likely related to sites where new eruptive fissures may open in the near futuredue to backward propagation of extensional tectonic stress.

© 2016 Elsevier B.V. All rights reserved.

Keywords:Mt. EtnaSoil CO2

Soil temperatureHidden faultsStructural framework

1. Introduction

Mt. Etna volcano (Sicily, Italy) is probably one of the best studied ex-amples of a basaltic volcanowith a close interplay between gravitationalspreading, slope failure and passive magma intrusion at shallow depth(McGuire et al., 1990; Groppelli and Tibaldi, 1999; Acocella and Neri,2003; Neri et al., 2004, 2009; Bonforte et al., 2011; Currenti et al.,2012a; Acocella et al., 2013; Falsaperla and Neri, 2015). In particular, acatastrophic flank collapse occurred about 10 ky ago, producing debrisavalanches and landslides, which formed a hugemorphological depres-sion called Valle del Bove (Calvari et al., 1998, 2004 and reference there-in). The important role that slope failure plays in governing both thetectonic settings and the evolution of volcanoes is nowwidely acceptedandproven (Borgia, 1994; Voight and Elsworth, 1997; VanWyk deVries

ia, Italy. Tel.:+39095 7165829.manco).

and Francis, 1997; Delaney et al., 1998; Elsworth and Day, 1999,Amelung and Day, 2002; Tibaldi, 2004; Cecchi et al., 2004; Siniscalchiet al., 2012). In particular, massive gravitational failuremay induce sud-den decompression of magma reservoirs with consequent possible pro-duction of huge explosive eruptions (Voight et al., 1981; Carracedo et al.,1999; Neri et al., 2008a).

After the strong 2002 flank eruption, slope failure atMt. Etna has in-creased dramatically, affecting its entire eastern flank and part of thesouthern and north-eastern ones (Neri et al., 2004, 2009; Solaro et al.,2010, and references therein). During the same period, evident progres-sive fracturing has occurred on the top of Etna. This affected not only themorphology of the volcano summit, but also the stability of its summitcraters, including their shallow plumbing systems, with a strong impacton the position of new vents during recent eruptive episodes (Neri andAcocella, 2006; Giammanco et al., 2007; Neri et al., 2011a; Vicari et al.,2011; Cappello et al., 2012; Ganci et al., 2012; Del Negro et al., 2013).It is therefore important to accurately map all possible faults and

80 S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

fractures onMt. Etna, especially on its summit, in order todevelop struc-tural models capable of showing the present state of structural weak-ness and possibly forecasting its future development.

Unfortunately, classic geological surveying of existing tectonic struc-tures is not always successful on active volcanoes such as Mt. Etna, be-cause the very frequent and sometimes large production of lavas andtephra normally conceals most, if not all, of the tectonic lineaments nearits active craters, especially close to the volcano summit (Behncke et al.,2005; Neri et al., 2008b). In these cases, soil gas surveying may provideadditional information on hidden geological structures. It is known thatfaults have a high crustal permeability that allows for the leakage ofdeep magmatic gas. This mechanism acts at various scales, having beenfirst recognized along major fault zones across the Eurasian plate (e.g.Irwin and Barnes, 1981). OnMt. Etna, almost every fault is a site of anom-alous diffuse degassing, particularly of CO2 and radon (e.g. Giammancoet al., 1998, 1999, 2010; Neri et al., 2011b; Bonforte et al., 2013). Diffusefault-driven degassing of CO2 from the flanks of Mt. Etna contributes sig-nificantly to the huge total amount of this gas released into the atmo-sphere (Allard et al., 1991; D'Alessandro et al., 1997; Aiuppa et al., 2004;Hernández et al., 2015). In geothermal areas or near the active summitcraters of volcanoes, soil CO2 emissions are often associated with heatanomalies in the ground, as CO2 and high-enthalpy fluids (essentiallywater vapor) have similar origin (i.e. magma or hydrothermal reservoirs)and both follow the same transport mechanisms (Aubert and Baubron,1988; Chiodini et al., 2001, 2005; Fridriksson et al., 2006). Soil tempera-ture is therefore a parameter that can indicate the efficiency of the processof gas transport to the surface in relation to the depth of the gas source.Slow gas transport or a gas source that is too far from the surface trans-lates into complete steam condensation deep in the ground with no de-tectable heat anomaly at the surface.

In order to assess the structural effects of gravitational spreading inthe summit area of Mt. Etna and to study its possible development intime, an extensive geochemical survey was carried out from October5th to 16th, 2008 on the summit part of Mt. Etna. The survey focusedon soil CO2 efflux and soil temperature measurements and the resultswere coupled with an updated structural survey of the same area.

2. Morphotectonic evolution of Mt. Etna

Mount Etna volcano (Italy) is located along the northern portion ofthe Malta Escarpment (ME), at the front of the Apennine-MaghrebianChain, and lies on Pre-Quaternary and Quaternary foredeep deposits(Fig. 1b). The volcano is located on a slabwindow formed by differentialroll-back of the subducting Ionian lithosphere with respect to the conti-nental Sicilian lithosphere (Doglioni et al., 2001, and referencestherein).

The tectonic setting of Etna is characterized by an E–W oriented ex-tensional regime, asmanifested by theNNW–SSE trending TranstensionalFault System(Timpe Fault System— TFS; Fig. 1b) cutting the lower Eflankof the volcano (Corsaro et al., 2002; Monaco et al., 2008; Azzaro et al.,2012). Quaternary compressive features affect the S and the NE peripheryof the volcano and are related to the southward migration of theApennine-Maghrebian Chain (Lanzafame et al., 1997; Catalano et al.,2004). These studies suggest that a N–S oriented compressive regime isassociated with the E–Woriented extension.

Volcanic activity in the Etna area started more than half a millionyears ago (De Beni et al., 2011) both with submarine and subaerialfissural eruptions that covered large portions of the territorywith volca-nic products that, however, did not build up important reliefs (Brancaet al., 2004, 2008, 2011a, 2011b). About 200,000 years ago, fissural vol-canic activity evolved into a central-type one and huge strato-volcanoesbegan to be build up, whose eruptive axes shifted over time from SE toNW (Tanguy et al., 2007). Between ~60,000 and 15,000 years ago thelast of those strato-volcanoes, named Ellittico, produced very violent ex-plosive eruptions that led to the formation of a caldera collapse whoserim at present crops out in the Pizzi Deneri-Piano delle Concazze

(2800 m) and Punta Lucia (2932 m) areas (Fig. 1). Inside this caldera,volcanic activity resumed roughly along the same eruptive axis, formingthe present volcanic centre of Mongibello. Detailed information aboutthe stratigraphy of Etna is available in Azzaro et al. (2012); Brancaet al. (2004, 2008, 2011a, 2011b) and De Beni et al. (2011).

Etna is one of the best examples of a volcano that has undergonerapid alterations to summit morphology due to the constructive/de-structive processes associated with magmatism and tectonism(Behncke et al., 2004; Neri et al., 2008b). Today's summit cone showsa somewhat buried crater rim at ~2900 m above sea level (a.s.l.),which is part of the caldera rim formed after the 122 B.C. plinian erup-tion (Coltelli et al., 1998; Cratere del Piano in Fig. 1). Since then, minorcollapses have affected the summit crater area, particularly during theviolent 1669 flank eruption (Corsaro et al., 1996; Chester et al., 1985;Hughes et al., 1990; Branca et al., 2015). The present-day summit regioncomprises the Central Crater, divided in Voragine (VOR) and BoccaNuova (BN), surrounded by three younger craters named NortheastCrater (NEC), Southeast Crater (SEC) and New Southeast Crater (NSEC,grown on the eastern flank of the SEC), respectively formed in 1911,1971 and 2011 (Chester et al., 1985; Vicari et al., 2011; Del Negroet al., 2013; Behncke et al., 2014; Fig. 1).

The upper portion of the volcano (N1500 m) is characterized bythree main “rift zones” that radiate from the summit (Neri et al.,2011a; Cappello et al., 2012): the NE Rift, the S Rift and the W Rift(Fig. 1b). These rifts do not tap deep magma, but are frequently fed bydikes coming from the central volcanic conduit rather than from an un-derlying shallow magma chamber (Bousquet and Lanzafame, 2001;Acocella and Neri, 2003; Neri et al., 2011a).

Etna's summit area is also affected by extensional processes in partrelated to the seaward displacement of its eastern and southern flanks(Borgia et al., 1992; Solaro et al., 2010; Bonforte et al., 2011; Ruchet al., 2012) that involve an on-shore area of N700 km2 (Neri et al.,2004). This unstable area is confined to theN by the Pernicana Fault Sys-tem (PFS; Fig. 1b; Neri et al., 2004) and to the SW by the Ragalna FaultSystem (RFS; Fig. 1b, Neri et al., 2007, Branca et al., 2011b). Wide frac-ture fields formed both around and inside the summit craters, andafter 1995 these fractures developed into a main N–S structural system(Fig. 1; Neri and Acocella, 2006). In 1998–2001, this system consisted ofa N–S fracture zone with orthogonal extension. In 2004, the fracturespropagated towards the SE, cutting the SEC and triggering the 2004–2005 eruption (Neri and Acocella, 2006). On January 12, 2006, a power-ful explosive episode occurred atVOR and deeply changed themorphol-ogy of the summit area (Giammanco et al., 2007). After this activity, theridge of rock separating the VOR from the BN was almost entirelydestroyed and the two summit vents today have a common rim whichborders a new single and wider crater (Fig. 1).

In January 2006–2007, Etna produced several short-lived eruptiveparoxysms (Behncke et al., 2008) and a long-lasting (~14 months)flank eruption in 2008–2009 (Bonaccorso et al., 2011). During the par-oxysmal episodes, phreatomagmatic explosions and pyroclastic densitycurrents were at times produced by the SEC and were accompanied bythe collapse of large portions of the E flank of the SEC cone (Neri et al.,2008b). Lava fountaining resumed in January 2011 (Vicari et al.,2011), producing 53 eruptions (updated to the first half of June 2015)building a huge pyroclastic cone (the New Southeast Crater, Fig. 1) lo-cated on the eastern flank of the SEC (Ganci et al., 2012; Behnckeet al., 2014).

3. Methods and results

3.1. Field methods

Measurements of CO2 efflux from soil were made adopting the dy-namic accumulation chamber method (Parkinson, 1981; Chiodiniet al., 1998), which consists of measuring the rate of increase of theCO2 concentration inside a cylindrical chamber with its open end set on

Fig. 1.Map of Mt. Etna with the study area highlighted. (a) DEM of the summit region of Mt. Etna, and recent (post-1991) eruptive and dry fissures (black lines). The Ellittico and Crateredel Piano Calderas are marked by dotted lines. VOR = Voragine, BN= Bocca Nuova, NEC= Northeast Crater, SEC = Southeast Crater, NSEC New Southeast Crater. Inset (b) reports themain rifts and the unstable sector (1) of Mt. Etna; (2) inferred frontal boundary of the unstable sector; (3) Etna volcanics; (4) sedimentary basement; (5) main faults; (6) motion of theunstable sector; (7) uncertain/buried faults; PFS, RFS = Pernicana and the Ragalna Fault Systems, respectively; TF = Timpe Fault System.

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the ground. The chamber has an internal fan to mix the gases and is con-nectedwith a portable NDIR (nondispersive infrared) spectrophotometer(systems used: Mod. EGM 4, PP Systems, U.K. and Mod. LICOR-800 in aportable West System CO2 efflux meter, Italy). The change in concentra-tion during the initial measurement is proportional to the CO2 efflux.This is an absolute method that does not require corrections linked tothe physical characteristics of the soil. The average error was about±5%. Analytical error associated with a single measurement was about±5% and the reproducibility in the range 100–10,000 g m−2 d−1 wasabout ±10%. Soil temperature values were measured at a depth ofabout 15 cmbelow the surface using a portable thermocouplewith digitaldisplay (accuracy 0.1 °C). The surveywasmadeduring a ten-day period inOctober 2008, with stable weather conditions.

A total of 1442 sites were surveyed for soil CO2 efflux and soiltemperature (Figs. 4 and 5). The surveyed area covered a surface ofabout 9 km2, including the summit part of Mt. Etna, roughly above2600 m a.s.l., the uppermost part of the NE flank, above 2700 m a.s.l.,and also a large portion of the upper southern flank of the volcano,above about 2500 m a.s.l. (Fig. 1). The spatial distribution of measure-ments as well as their density was strongly affected by logistics, as nomeasurement could be carried out on rough lava or near dangerousareas.

3.2. Statistical analysis of data

The results of the geochemical survey are summarized in Table 1. SoilCO2 efflux values ranged from non-detectable values (b0.01 g m−2 d−1)to about 37,600 g m−2 d−1, with arithmetic mean of about397 g m−2 d−1, standard deviation of about 1889 g m−2 d−1 and a me-dian of 0.82 g m−2 d−1. Soil temperature values ranged from 0.4 to128 °C, with arithmetic mean of 18.9 °C, standard deviation of 15.9 °Cand median value of 14.1 °C.

The divergence between geometric mean and median of soil CO2 ef-fluxes and the high positive values of the skewness obtained from theirfrequency distributions are indicative of a surplus in relatively high CO2

values, thus suggesting a log-normal distribution of the data. The distri-bution of soil CO2 efflux data showed a polymodal shape, which is evenmore evident in the histogram of the lognormally distributed CO2 effluxvalues (Fig. 2a). In order to check the polymodal distribution of soil CO2

data, logarithmic probability plots Sinclair (1974) were used for soil CO2

sample points, assuming a lognormal distribution of values. For each pop-ulation the arithmetic mean (Mi) and their respective standard deviation(σi) were calculated. The logarithmic probability plot of the efflux data(Fig. 2b) indicates four inflection points, respectively at the percentiles31.9, 64.4, 90.1, and 97.6, suggesting the presence of 5 distinct popula-tions. Population I corresponds to lowest efflux values (all lower than0.01 g m−2 d−1) and is assumed to be related to air-saturated soil withnomagmatic/hydrothermal gas efflux (values lower than the instrumen-tal limit of detection, 0.01 gm−2 d−1). The average soil CO2 efflux (φCO2)values of the four populations with values higher than 0.01 g m−2 d−1

(populations II to V) were 1.51 g m−2 d−1, 202.03 g m−2 d−1,

1465.30 g m−2 d−1 and 9669.10 g m−2 d−1, respectively. Efflux valuesabove 0.01 g m−2 d−1 reflect increasing gas emissions from a magmat-ic/hydrothermal source, due to the complete absence of vegetation inthe summit region of Etna and hence of biogenic sources of CO2. In partic-ular, populations IV and V have efflux values higher than 809 gm−2 d−1,and are therefore representative of areas dominated by high CO2 advec-tive effluxes, for which gas is transported towards the surface bypressure-driven viscous flow. Populations II and III are likely to involvecombinations of diffusive and advective gas flow.

Similar results are obtained from the analysis of soil temperature data.The log-normal distribution of these values is clearly shown in the histo-gram of log values of this parameter (Fig. 3a). Although the shape of theirdistribution appears more regular than soil CO2 effluxes, the log values ofsoil temperature seem to have a polymodal distribution, too. This as-sumption was confirmed by the logarithmic probability plot of the

temperature data (Fig. 3b). Four main inflection points were recognized,respectively at the percentiles 14.4, 68.8, 97.0 and 99.5, suggesting thepresence of 5 distinct populations. The average soil temperature valuesof the five populations were 4.35 °C, 12.98 °C, 31.43 °C, 73.21 °C and108.34 °C, respectively. Apart from population I, whose low temperaturevalues would reflect the temperature condition of air-saturated soil, theother populations would represent increasing contribution of heat frominput of high-enthalpy fluids (mostly water vapor). In particular, popula-tionVhas a few temperature values higher than the boiling point ofwaterat the average altitude of sampling (about 90 °C), therefore indicatingheat input from supercritical fluids, which is a typical condition of the fu-maroles near the active crater rims at Etna.

3.3. Spatial distribution of soil CO2 and soil temperature

Soil CO2 effluxes and soil temperature valueswere analyzed for theirspatial distribution using the sequential Gaussian simulation (sGs) algo-rithm by the program sgsim within the geostatistical software GSLIB(Deutsch and Journel, 1998). The sGs method consists of producing nu-merous simulations (100 in the presentwork) of the spatial distributionof a parameter. Because the sGs procedure requires a multi-Gaussiandistribution, a non-normally distributed data set is first transformedinto a normal distribution by a normal-score transform (Deutsch andJournel, 1998) and the resulting transformed data are then used in thesimulation procedure. The normal score data are then backtransformedinto simulated values of the original variable. In order to visualize thesimulations results, we used probability maps that report the probabil-ity that at each location the simulated value, obtained from the 100 sim-ulations, is higher than a selected threshold. Such maps help define theshape and the extension of diffuse degassing structures with a greaterreliability than classic interpolationmethods (such as Kriging)when es-timating the parametric values in un-sampled sites, as described byCardellini et al. (2003).

Figs. 4 and 5 show, respectively, the spatial distributions of CO2

efflux and soil temperature values in the investigated area, based onthe results of the sGs simulations. In the maps, the known volcano-tectonic features are also shown. It is clear that anomalous values ofsoil CO2 efflux follow a similar pattern of distribution as those of soiltemperature. The highest values of both parameters were found alongfaults and volcano-tectonic lineaments, in particular along the craterrims of the summit vents of the volcano, along and near the 2008–2009 eruptive fissure, that were still actively emitting lava at the timeof our survey, and on the 2001 and 2002–2003 eruptive cones. Otherconcurrent soil CO2 and soil temperature anomalies were found: i) atthe southern foot of the SEC; ii) just NNE of the NE crater; iii) alongthe 1991–1993 fissure that propagated towards the SE starting fromthe eastern foot of the SEC; iv) along the prolongation towards the SWof the 2006–2007 eruptive fractures located south of the summit cone.Anomalies of both parameters located just north of the 2002–2003eruptive cones, in a site named Torre del Filosofo (TdF, Fig. 1), are asso-ciatedwith an old fracture field characterized by considerable fumarolicactivity (maximumoutlet temperature in the area of about 83 °C) due toboiling of a shallowwater table and intense diffuse degassing related toactive gas release from the central feeder system of the volcano (Aubertand Baubron, 1988; Pecoraino and Giammanco, 2005; Alparone et al.,2005).

The 1991–1993 fissure had already been surveyed for soil tempera-ture and for diffuse gas emissions in recent years, particularly at a site(named Belvedere in Fig. 1) with visible steamy ground associated witha thermal anomaly (Alparone et al., 2004; Pecoraino and Giammanco,2005;Giammanco et al., 2007). Chemical and isotopic analyses of gases is-suing from that site, carried out in the period 2000–2003, demonstratedtheir magmatic origin. Furthermore, anomalous changes of the geochem-ical parameters in the gas emissions from site Belvedere were well corre-lated with those observed in other fumarolic sites near the summit of the

Table 1

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

500592 4175994 2722 11.6 10.4 0.00 500615 4176822 2851 14.7 16.1 0.03500657 4175898 2705 10.9 8.3 0.45 500593 4176801 2850 14.8 15.1 0.00500632 4175804 2691 10.9 13.0 0.00 500584 4176798 2850 15.2 14.1 0.00500655 4175697 2671 11.8 15.4 3.78 500560 4176778 2852 13.2 25.1 40.77500737 4175644 2662 10.8 14.2 0.00 500517 4176760 2856 15.8 25.3 22.99500624 4175558 2658 10.8 12.1 0.00 500493 4176742 2857 13.8 18.4 40.29500534 4175510 2658 10.8 11.7 0.00 500476 4176729 2863 14.3 21.5 81.81500430 4175446 2655 10.0 8.2 0.04 500451 4176717 2864 14.2 18.3 1.28500350 4175341 2692 11.2 6.8 0.36 500426 4176714 2863 14.7 14.9 0.00500261 4175249 2620 11.6 15.6 0.62 500404 4176706 2865 14.0 15.6 0.18500188 4175156 2614 10.7 12.3 0.33 500391 4176707 2870 14.9 19.0 0.15500145 4175080 2591 11.0 11.7 0.15 500367 4176702 2873 16.9 17.0 0.58500157 4174968 2572 11.6 11.4 0.32 500356 4176699 2872 15.3 14.4 0.18500155 4174863 2561 11.0 17.6 0.00 500331 4176692 2874 15.2 14.8 0.00500161 4174762 2560 10.8 11.3 0.00 500309 4176683 2880 15.2 15.3 0.00500089 4174675 2538 11.1 15.3 0.10 500287 4176672 2879 15.1 16.1 0.00500024 4174599 2519 10.8 14.6 0.00 500264 4176665 2882 14.8 14.8 0.00499925 4174590 2502 9.7 14.4 0.00 500235 4176658 2883 14.7 14.1 0.00499825 4174598 2489 9.2 15.2 0.37 500227 4176653 2881 14.6 15.4 0.00499727 4174634 2481 13.7 14.1 0.46 500202 4176642 2885 17.4 14.8 0.13499679 4174579 2469 11.3 14.4 0.00 500189 4176635 2890 22.2 16.3 0.10499706 4174485 2446 11.4 9.2 0.29 500159 4176639 2900 19.3 39.3 612.35499568 4174498 2425 10.3 16.6 0.22 500136 4176639 2903 17.7 22.9 13.94499654 4174376 2411 10.5 16.5 0.00 500113 4176645 2911 13.4 57.6 1340.88499539 4174383 2394 10.8 17.2 0.15 500096 4176651 2913 13.9 70.7 1083.17499612 4174259 2373 10.7 14.3 0.24 500076 4176658 2913 14.6 59.0 1077.64499532 4174214 2369 10.1 15.8 0.17 500055 4176661 2913 14.2 37.9 191.31499562 4174129 2339 7.4 14.3 0.16 500032 4176667 2915 14.3 17.3 362.83499500 4173987 2321 9.4 13.7 0.12 500002 4176675 2914 16.7 16.3 0.00499571 4173889 2308 9.8 15.0 0.60 499982 4176685 2913 14.1 16.7 0.00499531 4173800 2269 9.2 16.6 0.00 499967 4176696 2919 12.4 15.4 0.00499492 4173700 2244 8.3 17.0 0.38 499933 4176711 2921 12.7 16.8 0.00499516 4173610 2219 9.9 16.1 0.14 499908 4176731 2922 13.6 19.6 0.19499484 4173513 2213 8.4 13.5 0.21 499895 4176740 2926 15.9 17.3 0.00499359 4173497 2210 8.2 15.3 0.83 499862 4176739 2920 17.4 16.6 0.03499505 4173424 2179 7.6 14.7 1.19 499902 4176650 2900 18.9 18.4 0.00499615 4173453 2168 8.6 17.3 0.00 499945 4176631 2904 19.5 18.3 0.00499619 4173337 2141 8.7 18.1 0.40 499994 4176613 2906 19.7 16.3 0.00499693 4173346 2138 8.3 13.3 0.82 499987 4176528 2911 15.9 32.3 0.21499639 4173220 2115 8.8 11.6 0.03 499959 4176494 2906 14.4 14.4 0.08499742 4173268 2107 9.4 17.5 0.12 499957 4176462 2902 13.8 14.3 0.00499848 4173233 2097 8.5 13.3 0.46 499951 4176441 2893 13.8 14.3 0.30499900 4173157 2071 7.6 13.2 0.56 499946 4176412 2892 14.2 13.3 3.87500014 4173117 2053 8.3 n.m. 0.00 499953 4176389 2896 14.5 14.1 0.51500124 4173057 2041 9.0 n.m. 0.00 499965 4176371 2896 14.1 18.3 19.83500198 4173040 2016 9.2 12.2 0.65 499971 4176333 2894 15.3 20.7 0.00500118 4172965 1998 8.4 n.m. 0.00 500008 4176306 2904 14.2 23.5 292.32500182 4172843 1962 8.8 15.6 0.00 500035 4176304 2908 13.5 58.2 52.13500017 4172831 1964 8.2 11.8 0.00 500042 4176306 2911 15.2 43.7 310.29499961 4172647 1928 8.5 13.4 0.00 500066 4176307 2917 13.3 66.1 270.68500114 4176775 2907 9.7 6.2 8.84 500092 4176327 2925 12.8 58.2 102.43500219 4176779 2906 12.6 2.6 0.00 500106 4176343 2927 14.3 43.1 16.14500309 4176777 2895 13.2 3.8 3.85 500119 4176357 2929 13.7 40.7 29.32500415 4176848 2882 9.7 8.0 0.00 500126 4176370 2931 13.2 24.9 41.35500508 4176782 2866 12.3 23.6 0.00 500138 4176392 2933 13.8 48.0 115.51500593 4176764 2852 8.7 24.2 164.86 500144 4176413 2933 14.7 48.7 469.01500611 4176671 2841 11.6 4.3 0.00 500149 4176429 2936 15.1 59.8 939.02500578 4176559 2824 9.8 6.4 2.13 500156 4176458 2936 12.9 39.3 1659.49500561 4176459 2810 14.4 3.8 6.92 500143 4176482 2938 12.1 53.7 612.53500600 4176415 2793 11.3 6.8 0.00 500129 4176494 2940 14.3 48.3 309.59500566 4176323 2781 11.0 6.9 1.49 500126 4176507 2931 14.2 34.8 0.00500649 4176249 2753 11.6 4.6 0.85 499856 4176848 2952 18.3 10.5 0.24500633 4176108 2740 12.1 2.4 0.53 499888 4176839 2948 23.3 12.1 0.00500201 4172923 1987 8.6 12.4 4.86 499911 4176828 2947 20.2 12.6 0.72500138 4172843 1966 9.7 10.7 0.47 499939 4176826 2946 25.8 11.2 0.00499924 4172779 1960 8.5 11.8 2.26 499968 4176822 2948 21.8 11 0.00499987 4172711 1943 9.6 14.8 0.00 499988 4176819 2948 19.6 11.9 1.44499201 4177160 2979 5.9 10.1 0.07 500019 4176810 2945 21.5 17.2 580.56499104 4177218 2988 5.5 3.6 0.29 500047 4176808 2942 22.3 25 520.32498979 4177257 2988 5.2 2.4 0.02 500076 4176809 2941 22.2 16.4 48.48498931 4177373 3003 7.1 1.8 0.00 500108 4176814 2938 23.7 15.8 1.20498840 4177414 3002 8.0 4.5 0.00 500134 4176820 2932 23.8 15.7 0.00498768 4177505 3002 6.9 2.8 0.06 500160 4176820 2929 24.6 15.6 0.00

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83S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

498724 4177609 3007 6.7 3.1 0.00 500187 4176828 2926 24.4 13.9 0.24498677 4177716 3014 5.7 3.1 0.00 500205 4176824 2928 24.6 14.6 0.00498635 4177827 3022 3.7 4.2 0.00 500234 4176843 2925 24.6 14.5 0.00498577 4177940 3029 3.2 3.5 0.05 500268 4176847 2923 23.2 16.3 1.44498543 4178033 3033 4.6 2.5 0.27 500291 4176854 2915 23.1 9.3 0.00498655 4178181 3066 5.1 1.4 0.00 500337 4176863 2907 22.8 13.6 0.58498762 4178239 3089 4.8 2.1 0.00 500353 4176877 2907 26.9 14.3 0.00498825 4178349 3101 3.8 n.m. 0.00 500390 4176897 2894 23.7 14.8 0.24498895 4178425 3111 5.2 n.m. 0.00 500405 4176899 2890 24.9 15.3 0.00498989 4178518 3113 6.1 0.8 0.00 500418 4176897 2889 23.9 34.7 1113.84499000 4178634 3112 5.5 2.5 0.00 500447 4176920 2887 25.8 39.8 1948.56499005 4178758 3104 3.7 5.7 0.00 500470 4176937 2885 24.9 18.7 94.32498971 4178855 3081 8.1 1.5 0.00 500491 4176950 2875 21.1 14.6 0.00498961 4178944 3065 4.1 n.m. 0.15 500518 4176968 2873 23.1 15.2 0.00498907 4179006 3044 4.0 2.2 0.00 500539 4176979 2872 25.1 16.6 0.00498838 4178929 3036 6.6 2.4 0.05 500561 4176997 2866 23.8 16.3 0.00498809 4178976 3029 6.0 n.m. 3.15 500587 4177008 2864 22.6 15.5 0.00498741 4179036 3005 8.1 0.9 0.24 500610 4177020 2865 24.7 16.6 0.00498787 4179151 2991 8.5 2.4 0.05 500631 4177042 2862 25 16.2 0.00498823 4179259 2981 6.3 2.4 0.00 500639 4177068 2862 23.4 16 0.24498913 4179330 2996 7.0 1.3 0.12 500654 4177081 2865 23.8 14.9 0.00498977 4179422 2966 7.9 1.5 0.00 500666 4177105 2866 24.2 15.2 0.48499027 4179521 2958 6.1 0.9 0.03 500691 4177084 2862 24.9 15.1 0.00500694 4180111 2775 11.6 5.6 0.00 500678 4176772 2839 22.8 27.8 219.60500630 4180068 2802 9.6 3.8 1.17 500656 4176742 2834 23 23.1 627.60500592 4179972 2817 11.0 3.2 0.00 500635 4176721 2827 22 28.7 244.80500554 4179877 2830 9.2 2.5 0.00 500618 4176698 2826 21.7 29.8 220.56500467 4179857 2843 10.1 1.2 1.17 500598 4176692 2838 19.5 35.2 488.16500391 4179862 2857 8.2 3.2 0.64 500568 4176695 2837 18.4 15.9 12.96500288 4179824 2873 10.4 1.6 0.00 500549 4176675 2842 21.6 23.3 243.12500171 4179835 2881 9.4 3.6 0.00 500543 4176675 2844 20.7 19 185.52500208 4179762 2891 8.2 1.0 0.00 500510 4176661 2849 21.8 17.8 219.36500175 4179750 2902 11.9 2.3 1.99 500487 4176650 2852 22.3 16 19.20500081 4179703 2913 8.7 1.3 0.00 500465 4176637 2848 27.9 15.5 0.00499994 4179642 2932 8.6 1.3 0.63 500439 4176629 2851 26.4 14.6 2.88499892 4179626 2947 10.7 1.4 3.65 500422 4176623 2852 22.4 15.8 0.24499806 4179633 2952 7.4 0.6 1.16 500396 4176614 2860 23.8 16.1 0.00499691 4179612 2960 5.9 0.4 1.27 500379 4176611 2857 25.1 16.2 0.00499567 4179611 2969 7.9 0.8 1.58 500355 4176598 2864 24 14.4 0.00499445 4179599 2964 6.9 1.7 1.37 500319 4176596 2865 25.3 16.6 0.00499331 4179610 2957 7.9 1.8 1.26 500285 4176584 2874 23.7 16.3 0.00499214 4179641 2958 9.4 0.5 0.00 500263 4176572 2875 22 15.6 0.24499117 4179591 2956 12.0 2.4 2.28 500236 4176564 2876 22.2 15.4 0.48499051 4178664 3131 8.1 1.8 0.00 500222 4176564 2884 22.2 15.1 0.00499081 4178653 3135 7.8 1.4 0.65 500197 4176562 2887 23.3 14.7 0.00499111 4178643 3146 8.6 0.7 0.15 500173 4176562 2893 23 15.1 0.24499144 4178645 3146 7.5 1.3 0.25 500149 4176571 2892 23.3 50.7 2397.60499183 4178645 3162 9.5 7.0 0.13 500151 4176571 2902 22.3 18.6 2.16499206 4178628 3174 6.4 0.8 0.34 500106 4176587 2899 20.6 15 0.00499237 4178608 3179 6.0 1.1 0.00 500084 4176598 2900 22.4 26.4 2.40499264 4178602 3179 6.7 0.9 0.34 500059 4176600 2903 23.7 15.9 0.00499286 4178589 3184 6.8 1.4 0.83 500029 4176604 2909 23.6 17.8 0.24499307 4178589 3194 7.6 2.0 2.08 500602 4176661 2830 21.2 20.9 49.44499331 4178581 3202 7.5 1.1 0.63 500602 4176661 2834 21.1 31.4 246.96499356 4178578 3206 7.5 1.6 0.41 500638 4176699 2828 21.1 21.7 60.72499361 4178548 3211 7.7 0.7 0.00 500653 4176722 2826 23 18.1 0.00499376 4178537 3222 6.9 1.2 0.00 499869 4176802 2943 6.6 24.4 1.55499379 4178504 3220 8.1 1.2 0.23 499894 4176797 2936 21.4 8.0 0.00499383 4178448 3235 6.9 1.4 0.54 499929 4176789 2937 19.7 7.9 1.14499368 4178425 3239 7.1 2.3 22.21 499957 4176774 2934 18.3 7.2 0.00499368 4178418 3236 10.1 32.5 257.62 499982 4176763 2932 17.9 8.5 1.86499367 4178411 3238 8.8 23.9 2495.72 500008 4176758 2933 18.4 7.7 35.69499369 4178401 3241 8.1 0.8 0.00 500039 4176757 2932 17.4 9.2 171.24499351 4178380 3240 7.2 8.2 3.53 500067 4176755 2934 17.3 14.2 151.84499336 4178359 3256 6.4 0.9 72.07 500096 4176753 2932 17.6 16.2 0.00499328 4178344 3262 20.4 33.5 428.55 500122 4176758 2930 18.8 10.5 1.25499333 4178333 3261 6.9 21.1 194.59 500148 4176755 2927 21.3 11.1 0.00499341 4178323 3260 7.3 11.2 320.60 500177 4176757 2921 20.7 8.8 0.00499339 4178317 3260 10.8 36.9 830.56 500207 4176756 2913 19.6 8.3 1.60499340 4178304 3260 10.0 19.3 383.67 500229 4176761 2904 20.7 9.5 0.00499333 4178311 3261 12.9 n.m. 9136.07 500253 4176757 2901 22.8 8.6 0.76499352 4178298 3263 10.6 20.6 148.74 500288 4176754 2905 19.8 9.7 0.00499342 4178296 3265 10.9 37.6 654.71 500308 4176756 2900 19.2 9.3 0.00499349 4178291 3262 10.6 25.3 484.93 500335 4176761 2894 18.4 10.1 0.00

84 S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

499365 4178294 3264 8.7 20.2 718.59 500355 4176771 2899 20.4 11.9 0.00499357 4178282 3268 8.8 34.3 1533.56 500357 4176776 2891 21.2 11.4 1.10499376 4178285 3269 7.8 21.3 1307.26 500381 4176788 2891 19.5 9.2 0.00499366 4178274 3270 8.9 23.3 1707.81 500398 4176802 2886 20.4 5.4 1.35499389 4178280 3273 9.6 29.9 182.17 500419 4176808 2882 20.2 11.3 27.28499371 4178270 3266 13.2 52.7 98.80 500448 4176814 2877 21.2 11.7 77.71499401 4178271 3269 10.5 18.5 1.00 500471 4176823 2873 21.3 15.9 0.00499381 4178262 3275 10.2 30.2 91.43 500502 4176829 2870 22.4 12.5 119.73499396 4178283 3268 10.7 37.8 691.01 500520 4176842 2871 23.9 27.8 6.78499399 4178263 3270 11.2 35.2 230.39 500536 4176852 2868 21.7 17.3 0.00499383 4178302 3266 13.5 50.4 1533.04 500562 4176864 2863 20.3 12.6 0.00499406 4178281 3269 19.8 70.0 1594.90 500587 4176874 2862 22.4 11.9 101.76499398 4178291 3272 9.3 73.0 537.60 500606 4176882 2862 23.0 19.5 0.00499384 4178318 3271 10.3 62.5 1699.25 500638 4176906 2854 19.9 15.6 1.23499388 4178319 3271 13.4 56.8 1347.15 500659 4176917 2850 20.7 11.9 0.00499365 4178318 3264 12.1 45.4 508.05 500664 4176938 2849 23.1 11.8 0.00499351 4178336 3260 8.9 40.0 758.65 500668 4176963 2853 21.4 12.8 1.32499351 4178346 3262 8.1 40.5 2047.28 500676 4176988 2852 21.7 12.2 1.07499366 4178346 3267 8.1 73.0 1511.72 500697 4177006 2848 24.8 9.3 0.00499379 4178364 3253 6.5 59.6 2568.90 500711 4177023 2848 24.2 9.8 1.58499359 4178356 3258 8.1 4.4 3.03 500726 4177043 2842 22.8 10.3 0.40499384 4178349 3276 7.5 56.4 1744.97 500733 4177060 2838 21.1 10.4 0.00499391 4178344 3278 9.1 79.0 146.80 500758 4177084 2828 21.1 10.7 0.00499399 4178341 3279 10.0 62.7 1464.67 500784 4177100 2824 22.1 14.1 0.00499392 4178365 3279 9.0 n.m. 7371.98 500778 4177069 2827 23.0 12.3 0.00499410 4178337 3279 9.7 76.4 1123.67 500776 4177044 2833 23.3 9.8 0.00499423 4178368 3272 13.4 21.3 2402.25 500776 4177009 2830 20.6 10.8 0.00499422 4178339 3284 4.3 72.2 1442.84 500729 4176859 2843 19.7 10.7 0.00499402 4178363 3274 13.4 51.5 1794.77 500714 4176854 2839 22.7 12.3 8.24499428 4178352 3274 11.0 43.9 1179.20 500697 4176823 2843 24.2 17.2 71.29499417 4178358 3280 n.m. 0.00 500684 4176815 2838 21.8 13.2 11.30499432 4178362 3285 11.1 65.7 1480.90 500660 4176784 2837 20.5 16.2 154.12499445 4178381 3281 10.2 32.5 1130.35 500650 4176778 2833 22.1 14.8 44.60499465 4178390 3266 12.3 43.6 2503.00 500629 4176775 2840 21.7 13.2 14.31499483 4178420 3285 13.7 41.2 1468.05 500597 4176769 2844 22.7 18.2 30.16499508 4178438 3270 11.8 35.8 2328.51 500572 4176748 2849 21.3 17.5 130.19499521 4178441 3278 11.0 47.0 1257.40 500557 4176742 2847 20.9 21.2 133.09499548 4178447 3275 10.6 42.3 952.05 500535 4176727 2849 21.6 24.4 146.13499569 4178443 3271 20.0 64.9 920.85 500517 4176728 2855 23.4 23.2 56.46499590 4178444 3275 9.3 30.0 125.31 500496 4176707 2855 22.3 20.2 16.82499613 4178444 3275 8.6 24.8 198.58 500480 4176690 2859 25.0 15.2 0.46499640 4178434 3275 10.7 18.1 360.14 500453 4176686 2857 23.6 14.3 0.00499665 4178430 3279 7.9 15.1 2.15 500432 4176681 2854 23.9 13.2 0.00499673 4178423 3277 7.7 14.8 41.62 500414 4176676 2857 23.1 12.9 0.00499702 4178414 3279 8.2 28.4 1408.23 500389 4176666 2864 21.9 14.2 0.00499721 4178404 3290 11.8 27.6 1107.72 500360 4176649 2865 23.9 14.1 0.00499740 4178388 3283 12.1 32.6 138.80 500348 4176641 2871 24.9 13.8 0.00499748 4178368 3282 9.9 33.9 142.82 500318 4176638 2870 24.3 13.6 0.00499751 4178346 3278 7.8 18.3 544.07 500300 4176632 2873 24.1 13.9 0.00499734 4178351 3273 9.3 49.5 673.82 500271 4176622 2877 23.3 14.2 0.00499735 4178331 3271 9.8 18.3 3.00 500247 4176624 2873 22.3 16.8 0.00499717 4178344 3265 8.4 17.5 0.30 500227 4176611 2876 21.9 14.8 0.00499706 4178362 3262 9.1 3.9 3.02 500207 4176606 2881 24.1 16.3 0.00499685 4178366 3260 11.0 10.6 0.27 500190 4176597 2886 23.9 17.2 64.00499669 4178372 3260 9.8 16.6 11.03 500171 4176599 2890 23.3 18.8 0.00499652 4178384 3263 8.9 22.0 102.75 500150 4176601 2897 23.8 15.3 7.63499639 4178392 3263 9.1 25.8 46.73 500141 4176600 2900 28.2 22.4 0.00499617 4178401 3274 10.1 26.0 325.26 500109 4176614 2900 27.8 18.3 0.00499604 4178411 3277 10.1 22.0 35.98 500092 4176613 2903 25.6 16.4 0.76499597 4178419 3277 n.m. n.m. 148.25 500057 4176620 2908 26.3 17.4 13.67499587 4178423 3277 n.m. n.m. 102.41 500043 4176626 2910 26.1 17.4 0.00499619 4178439 3279 9.9 28.1 135.98 500019 4176633 2910 26.7 21.2 0.00499643 4178422 3277 9.0 12.4 60.20 499999 4176650 2916 24.8 20.2 0.00499663 4178417 3273 16.2 21.4 106.67 499972 4176653 2912 16.7 22.7 0.00499675 4178409 3270 12.1 21.4 306.45 499955 4176665 2909 23.2 17.4 0.00499694 4178395 3270 11.5 17.7 72.67 499937 4176671 2911 22.1 14.1 0.00499713 4178394 3271 11.0 28.3 840.48 499908 4176681 2914 21.5 17.6 3.20499726 4178374 3273 12.9 36.7 743.63 499887 4176688 2913 21.5 14.6 0.00499755 4178308 3274 12.0 31.5 1026.43 499864 4176698 2916 19.7 15.8 0.00499757 4178306 3273 10.0 34.0 1575.66 499843 4176662 2910 15.3 21.5 1.68499737 4178316 3267 9.7 20.0 0.20 499865 4176651 2905 20.8 16.7 0.00499726 4178322 3262 10.2 13.4 0.70 499924 4176636 2904 21.4 14.8 0.84499708 4178327 3256 17.9 12.2 8.38 499968 4176628 2904 20.5 16.5 40.25

(continued on next page)

85S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

499690 4178341 3250 11.0 12.4 0.00 499998 4176519 2921 19.7 28.3 598.27499671 4178352 3250 9.5 20.3 242.11 499987 4176483 2902 21.2 38.3 14.58499647 4178368 3252 10.3 20.4 82.98 499985 4176464 2897 20.7 32.9 0.00499621 4178359 3257 11.8 13.6 44.63 499992 4176442 2892 20.3 33.1 5.86499618 4178374 3262 11.0 19.9 18.81 499991 4176423 2887 19.1 33.3 12.91499591 4178393 3269 12.6 32.7 54.91 499986 4176395 2890 19.9 33.3 47.32499602 4178402 3272 10.9 22.9 30.92 499980 4176373 2897 19.3 26.4 573.88499583 4178417 3274 10.1 21.9 158.87 499976 4176348 2899 20.1 29.1 1.51499561 4178427 3275 10.1 24.6 1236.63 499989 4176312 2899 20.4 36.0 75.34499535 4178427 3275 12.9 33.9 808.14 499957 4176342 2899 19.4 31.2 143.19499541 4178438 3278 10.0 24.5 353.87 499940 4176361 2892 18.4 36.4 0.00499214 4178273 3275 8.2 15.6 2507.51 499922 4176392 2887 18.4 36.2 1.21499239 4178257 3269 11.4 25.1 149.40 499921 4176413 2893 18.0 37.3 0.49499236 4178246 3266 8.4 76.6 6650.08 499928 4176440 2907 19.3 34.9 2.35499235 4178226 3262 11.9 20.3 5018.82 499927 4176461 2904 19.3 36.8 0.00499240 4178217 3260 9.3 63.3 7808.66 499940 4176485 2900 21.0 34.2 0.00499223 4178183 3258 9.6 38.7 82.61 499964 4176504 2911 21.5 33.3 0.00499194 4178176 3258 7.8 36.8 1397.00 500000 4176525 2918 19.7 22.2 507.26499178 4178161 3258 9.1 34.1 659.65 500025 4176526 2918 19.2 39.4 7.90499162 4178135 3252 9.2 24.9 1017.12 500052 4176528 2925 20.3 34.3 362.01499174 4178098 3247 10.3 16.6 184.83 500090 4176515 2924 20.8 36.8 764.64499191 4178086 3250 11.7 20.8 774.11 500090 4176515 2924 19.4 38.4 0.11499202 4178053 3251 19.6 71.1 2312.79 500644 4175966 2713 12.4 11.1 0.12499200 4178032 3250 13.6 67.8 24088.78 500613 4175968 2712 12.8 10.9 0.23499205 4178008 3250 9.4 18.9 3532.77 500594 4175964 2712 11.7 10.4 0.13499239 4178003 3254 11.9 59.4 8319.19 500566 4175964 2722 11.3 11.9 0.13499236 4178010 3250 10.1 35.2 315.00 500542 4175965 2723 11.8 13.1 0.07499227 4178041 3247 16.3 34.9 1261.66 500520 4175961 2728 12.4 13.0 0.42499221 4178067 3248 11.6 80.2 5589.86 500505 4175964 2728 13.6 11.8 0.34499215 4178100 3244 12.1 35.7 76.27 500495 4175966 2729 12.8 12.0 0.17499215 4178133 3241 10.9 42.1 9705.64 500466 4175985 2734 12.8 11.3 0.29499233 4178141 3239 11.6 13.7 116.83 500446 4175984 2736 12.6 11.9 0.17499232 4178108 3239 13.5 26.6 134.02 500426 4175980 2735 15.1 10.4 0.35499241 4178069 3241 11.1 68.7 4042.68 500407 4175975 2743 14.6 11.1 0.38499255 4178050 3242 11.8 84.6 10619.09 500389 4175972 2741 14.0 14.0 0.25499248 4178011 3243 13.3 81.9 15747.60 500367 4175966 2742 13.8 11.7 0.31499273 4178028 3242 18.0 79.2 2499.97 500347 4175961 2740 13.9 11.9 0.72499264 4178050 3237 12.6 29.2 2597.08 500326 4175958 2741 13.9 13.5 0.21499266 4178075 3236 11.3 32.7 12512.27 500306 4175958 2745 14.1 12.9 0.35499270 4178114 3236 13.3 23.3 37.17 500295 4175949 2752 14.7 12.4 0.62499279 4178148 3237 10.8 14.1 267.67 500239 4175845 2731 13.3 9.1 0.15499315 4178106 3244 12.3 24.2 6351.32 500239 4175845 2731 22.2 13.3 43.42499296 4178081 3237 11.6 21.1 183.95 500264 4175853 2730 13.8 19.6 11.61499293 4178046 3243 11.7 34.6 1055.45 500284 4175855 2734 16.0 14.7 14.29499296 4177997 3244 12.9 79.7 4332.64 500299 4175862 2732 18.3 16.3 13.91499601 4178013 3275 10.8 56.8 451.76 500323 4175862 2730 15.5 17.1 2.19499620 4178044 3284 17.9 14.9 219.50 500346 4175860 2728 16.6 16.4 0.33499648 4178093 3290 19.1 31.6 997.15 500363 4175856 2722 17.5 13.9 1.05499688 4178071 3281 18.9 39.2 3421.40 500383 4175847 2715 17.2 13.3 0.00499640 4178046 3285 14.0 46.1 2085.60 500394 4175843 2716 16.2 12.4 0.28499531 4177974 3277 9.4 44.7 705.32 500407 4175843 2718 16.1 14.0 0.19499484 4177949 3276 7.8 38.6 350.65 500426 4175842 2714 17.3 14.1 0.39499436 4177933 3269 8.4 39.4 551.55 500447 4175838 2707 17.5 15.3 0.00499380 4177944 3266 9.4 65.9 8779.77 500473 4175836 2707 18.3 14.3 0.22499336 4177940 3267 11.3 80.4 10354.83 500484 4175836 2710 17.1 14.2 0.57499294 4177971 3267 9.2 63.5 6338.02 500510 4175838 2706 16.7 13.7 0.00499286 4178005 3265 11.1 82.1 10993.46 500524 4175852 2701 16.7 14.6 0.15499096 4178750 3130 9.4 1.9 0.63 500536 4175864 2703 17.6 16.2 0.33499150 4178775 3137 9.2 1.1 0.00 500570 4175848 2701 16.0 13.4 0.16499189 4178801 3141 10.5 1.3 0.53 500591 4175836 2700 18.8 13.4 0.13499217 4178799 3152 8.3 1.0 0.42 500622 4175988 2710 19.7 14.3 0.00499239 4178802 3149 7.3 1.5 0.35 500624 4175998 2720 15.9 12.7 0.00499271 4178805 3170 8.8 1.9 0.20 500647 4176002 2718 16.6 13.6 0.15499298 4178789 3182 9.1 2.1 0.11 500657 4176004 2717 16.5 16.2 0.18499322 4178786 3187 6.7 1.3 0.34 500688 4176005 2718 16.8 14.8 0.24499335 4178798 3195 6.6 1.6 0.13 500714 4176000 2713 16.4 14.5 0.00499353 4178779 3197 8.7 1.1 0.26 500740 4175995 2711 16.5 14.6 0.22499369 4178768 3200 6.7 1.7 0.65 500765 4175992 2710 21.6 13.1 0.10499389 4178757 3202 7.7 0.7 1.36 500792 4175993 2709 18.4 15.7 0.00499405 4178749 3204 6.9 0.9 0.50 500812 4175971 2698 15.3 15.8 0.00499420 4178736 3216 6.1 0.6 1.22 500833 4175973 2699 16.1 17.2 0.00499440 4178724 3222 7.0 0.6 1.31 500854 4175972 2685 16.0 14.9 0.00499434 4178693 3233 6.7 0.6 347.25 500847 4175952 2691 18.3 15.0 0.00499433 4178665 3240 7.3 2.5 38.27 500854 4175930 2691 19.9 15.4 0.14

86 S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

499451 4178650 3252 7.3 0.9 54.64 500865 4175928 2696 21.7 14.0 0.00499469 4178630 3256 6.9 0.8 12.96 500868 4175901 2694 19.9 16.9 1.14499471 4178602 3260 6.4 4.3 0.57 500881 4175894 2682 19.6 16.0 0.15499482 4178570 3262 6.8 2.4 0.37 500888 4175867 2675 17.6 15.2 0.00499500 4178548 3265 10.8 1.3 0.50 500883 4175849 2675 18.7 14.9 0.20499514 4178527 3268 9.2 0.7 0.15 500875 4175845 2675 19.6 17.6 0.20499526 4178522 3271 7.1 1.7 0.00 500853 4175841 2673 20.1 16.6 0.68499546 4178499 3276 6.8 1.8 36.31 500824 4175834 2674 20.2 16.1 0.00499532 4178470 3275 8.5 68.2 1722.31 500804 4175840 2678 19.4 14.1 0.85499586 4178480 3283 10.0 14.2 168.69 500788 4175828 2678 18.8 16.7 0.23499616 4178472 3284 8.2 14.9 262.28 500778 4175827 2677 20.5 16.1 0.15499638 4178474 3290 9.6 12.8 255.28 500749 4175818 2687 20.6 17.3 0.00499666 4178469 3298 8.2 11.9 117.82 500732 4175812 2684 20.3 16.2 0.00499693 4178469 3309 10.2 26.2 1600.34 500710 4175799 2683 21.3 15.4 0.00499717 4178480 3319 11.6 15.8 124.14 500699 4175792 2688 21.1 14.4 0.15499739 4178473 3315 11.7 19.9 175.65 500674 4175791 2683 22.4 15.3 0.22499761 4178487 3311 12.7 25.1 41.47 500652 4175792 2687 21.0 21.3 0.00499783 4178503 3316 15.7 19.6 13.91 500715 4175191 2594 25.3 20.0 0.08499735 4178443 3301 15.6 25.4 364.41 500701 4175196 2594 23.8 17.8 0.00499733 4178415 3291 12.1 28.3 806.58 500683 4175193 2601 22.8 18.9 0.03499739 4178289 3274 8.3 15.4 2.53 500659 4175193 2600 22.4 17.1 0.81499725 4178280 3275 7.3 7.8 269.89 500610 4175191 2598 18.0 16.4 0.13499722 4178272 3262 8.1 20.2 367.40 500589 4175193 2600 16.3 16.9 0.00499713 4178251 3261 7.7 40.7 906.63 500570 4175190 2605 15.0 17.9 0.00499695 4178238 3263 7.1 29.0 1641.53 500553 4175191 2605 19.8 15.1 0.40499685 4178225 3266 8.7 18.4 221.16 500523 4175198 2604 16.7 14.9 0.00499676 4178225 3283 7.6 29.1 357.75 500510 4175199 2605 16.6 15.6 0.20499661 4178194 3264 8.1 35.4 398.25 500487 4175206 2606 16.4 15.8 0.46499674 4178211 3260 8.9 10.6 306.83 500470 4175200 2607 16.4 15.4 0.00499671 4178236 3256 10.0 16.0 73.20 500449 4175199 2606 17.6 15.1 0.09499690 4178252 3251 9.1 12.8 60.80 500419 4175199 2607 17.7 13.3 0.14499698 4178272 3255 9.2 10.6 21.62 500403 4175202 2603 15.6 15.3 0.12499708 4178291 3250 7.9 10.2 2.00 500384 4175200 2606 15.6 13.1 0.08499718 4178308 3250 2.8 12.7 0.72 500359 4175181 2612 15.3 13.4 0.00499692 4178316 3252 13.1 17.3 0.87 500339 4175170 2605 14.7 13.1 1.40499666 4178325 3253 13.7 15.6 395.26 500319 4175158 2610 15.1 11.6 0.00499644 4178346 3261 7.8 17.5 214.06 500297 4175153 2606 15.0 12.9 2.47499622 4178315 3270 8.9 15.7 165.76 500280 4175135 2608 15.4 12.9 0.00499635 4178300 3257 8.7 24.8 715.05 500269 4175117 2608 15.4 12.3 0.00499640 4178281 3257 9.2 62.9 1782.50 500252 4175105 2601 15.4 12.7 0.31499631 4178256 3261 8.9 28.9 203.18 500235 4175080 2599 15.7 14.1 0.00499645 4178231 3260 8.5 28.6 468.44 500223 4175066 2592 15.3 14.0 0.06499644 4178213 3259 8.1 29.9 384.40 500216 4175048 2590 17.1 13.4 0.00499660 4178268 3260 7.6 49.9 977.19 500247 4175061 2600 19.3 7.8 0.22499660 4178297 3258 7.2 26.0 913.02 500279 4175090 2610 18.9 8.3 0.08499672 4178264 3257 5.3 7.9 249.66 500310 4175120 2630 17.9 11.2 0.00499676 4178280 3256 8.6 15.5 1032.79 500320 4175099 2640 18.2 11.8 0.00499676 4178298 3255 8.5 14.0 187.71 500325 4175080 2644 20.0 19.7 0.18499689 4178289 3260 5.6 8.2 127.21 500324 4175061 2641 19.6 13.4 0.00499642 4178319 3259 6.2 7.1 215.00 500329 4175042 2646 19.9 18.4 0.00499633 4178334 3262 7.5 7.0 230.54 500348 4175067 2649 18.4 21.7 2.74499082 4177256 2995 8.7 7.4 526.00 500366 4175089 2652 19.6 22.4 0.85499076 4177271 2997 6.6 6.2 14.71 500373 4175096 2655 17.4 18.2 0.36499073 4177289 2999 10.6 6.6 13.99 500330 4175006 2650 18.8 20.9 0.00499068 4177316 3002 10.8 6.7 9.01 500347 4174989 2654 19.2 24.3 0.00499067 4177334 3005 13.8 6.5 7.88 500365 4174968 2654 19.4 37.9 16.80499080 4177364 3010 14.8 7.9 22.02 500390 4174955 2658 17.1 33.1 14.32499084 4177372 3014 13.3 7.9 18.75 500416 4174954 2661 18.2 33.2 2.53499086 4177400 3021 11.9 8.5 23.65 500425 4174973 2666 18.9 37.6 6.10499098 4177422 3025 12.9 8.1 15.67 500434 4174981 2669 20.0 70.0 17.50499102 4177436 3027 12.3 8.6 27.50 500467 4174999 2671 19.3 28.2 0.00499106 4177455 3034 11.9 8.5 342.91 500355 4175487 2653 21.4 15.9 0.00499091 4177479 3035 13.4 13.4 30.63 500374 4175505 2656 18.7 15.5 0.00499086 4177476 3039 11.4 13.9 828.39 500396 4175510 2657 20.9 15.4 0.00499091 4177512 3044 8.8 9.7 66.33 500420 4175518 2659 19.2 15.3 0.00499105 4177529 3049 10.1 5.9 43.31 500442 4175529 2660 20.6 15 0.48499105 4177560 3053 10.7 5.9 15.43 500474 4175533 2661 20.9 14.7 0.24499122 4177574 3060 10.4 5.4 26.23 500501 4175552 2667 21.2 14.9 0.24499117 4177592 3069 7.8 6.6 1412.83 500512 4175568 2666 22.1 14.6 0.00499137 4177603 3072 8.4 7.5 561.45 500532 4175577 2668 22.3 15.5 0.00499132 4177634 3078 7.1 9.8 1543.22 500550 4175602 2667 20.7 15.3 0.00499126 4177656 3083 8.3 11.3 3720.17 500568 4175613 2668 19.9 15.6 0.00499121 4177684 3088 7.8 7.6 566.58 500588 4175640 2665 20.6 14.6 0.00

(continued on next page)

87S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

499115 4177705 3095 8.8 6.8 1596.51 500616 4175653 2663 24.4 15.8 0.00499127 4177733 3105 9.8 8.3 140.03 500649 4175670 2664 22.1 15.9 0.24499110 4177759 3113 7.4 5.3 37.46 500662 4175685 2666 21.6 16.2 0.00499099 4177791 3116 8.4 8.6 150.99 500684 4175704 2669 21.4 16.3 0.00499105 4177829 3129 8.6 8.4 34.55 500710 4175706 2668 20.8 16.4 0.00499086 4177846 3128 7.3 6.8 153.48 500770 4175724 2667 20.6 15.7 0.00499073 4177862 3133 8.6 4.2 65.17 500759 4175712 2666 22.3 15.9 0.00499063 4177886 3138 10.1 6.7 243.47 500793 4175730 2663 21.8 16.1 0.96499071 4177913 3148 10.7 11.6 993.88 500824 4175716 2659 21.5 15.5 0.00499063 4177941 3155 9.9 8.1 677.37 500849 4175718 2656 25.3 15.8 0.00499069 4177969 3163 10.6 10.2 73.27 500871 4175724 2654 18.2 11.1 0.24499086 4177994 3172 8.9 8.2 85.74 500877 4175707 2650 36.3 12.2 0.00499098 4178019 3177 9.2 5.0 3.46 500869 4175691 2649 23.6 12.4 0.00499096 4178044 3188 10.2 4.9 20.23 500857 4175672 2650 21.6 10.1 0.00499109 4178072 3196 10.6 44.0 7.36 500852 4175646 2648 28.7 10.6 0.24499099 4178094 3205 6.2 5.4 46.25 500850 4175621 2641 22.4 11.3 0.00499113 4178126 3216 5.7 0.8 32.95 500842 4175591 2648 20.1 10.1 1.20499111 4178092 3225 5.3 1.8 2.05 500827 4175572 2646 20.6 10.9 0.26499162 4178120 3232 6.6 1.7 1.73 500809 4175553 2646 21.6 10.9 0.26499193 4178134 3240 8.0 63.3 2940.69 500787 4175539 2644 23.6 13 0.24499203 4178102 3241 8.1 69.9 1302.74 500762 4175528 2638 20.9 11.1 0.48499211 4178170 3245 7.1 29.4 1004.25 500743 4175516 2639 20.8 12 0.00499252 4178142 3241 8.1 24.9 352.99 500720 4175515 2636 26.1 12.2 0.00499304 4178119 3241 9.5 20.5 97.94 500694 4175510 2637 23.6 11.3 0.00499332 4178089 3249 11.2 71.8 1181.36 500670 4175506 2640 21.3 11.8 0.00499353 4178082 3242 13.6 30.8 162.39 500642 4175500 2645 21.6 11.7 0.00499354 4178035 3241 8.5 10.9 21645.17 500615 4175490 2649 22 11.9 0.00499368 4178046 3241 10.9 25.4 257.41 500609 4175460 2642 23.9 11.9 0.48499371 4178013 3239 11.6 19.7 43.58 500601 4175431 2641 21.2 11.8 0.00499402 4178014 3240 8.6 13.5 175.71 500604 4175404 2639 26.7 13.4 0.24499415 4177983 3244 6.1 49.9 780.84 500580 4175391 2637 23.9 12 0.24499419 4177965 3246 7.1 48.3 2687.78 500555 4175380 2635 26 12.1 0.24499394 4177976 3245 7.2 80.4 1136.74 500532 4175373 2635 27.3 11.7 0.00499359 4177969 3245 9.3 25.9 163.58 500507 4175379 2637 19.3 12.1 0.00499325 4177957 3241 8.2 20.2 2952.39 500481 4175381 2638 19.7 12.9 0.00499326 4178003 3242 6.7 17.2 55.18 500452 4175377 2639 23.4 12.7 0.00499345 4177993 3246 8.1 69.4 7821.16 500425 4175373 2635 21.3 12 0.00499323 4177991 3246 7.7 21.2 195.34 500398 4175371 2635 29.8 12.4 0.24499301 4178023 3245 7.8 24.4 182.15 500373 4175380 2637 23.7 12.3 117.84499317 4178039 3245 13.2 75.4 181.72 500341 4175380 2638 22.9 16.3 0.00499315 4178063 3244 13.1 23.9 71.33 500005 4176280 2898 14.2 9.7 4.96499340 4178062 3242 10.9 28.5 84.72 500005 4176256 2891 19.8 9.7 9.22499387 4177927 3263 10.6 69.6 584.78 500000 4176232 2887 16.7 42.1 52.06499419 4177928 3264 8.6 30.2 577.72 499994 4176206 2880 19.0 45.8 24.22499444 4177902 3266 11.1 27.6 93.76 499982 4176185 2873 19.4 125.0 26.44499414 4177902 3259 11.4 34.6 519.63 499982 4176164 2875 21.8 59.6 17.17499401 4177873 3245 10.2 19.8 223.78 499985 4176144 2867 18.6 60.4 3.92499385 4177864 3232 11.5 25.9 927.70 499993 4176124 2870 18.8 31.2 4.46499364 4177845 3215 14.1 20.2 53.57 500003 4176111 2878 17.5 15.9 8.07499361 4177814 3206 13.0 20.0 92.41 500008 4176083 2878 16.7 10.9 5.07499347 4177786 3190 13.6 20.3 5.30 500018 4176068 2884 17.0 128.0 155.75499367 4177759 3181 14.2 15.4 72.07 500032 4176053 2880 16.3 29.1 26.55499370 4177733 3168 14.6 23.7 1311.17 500050 4176043 2886 16.8 78.8 821.09499378 4177713 3155 14.5 15.1 217.16 500072 4176049 2881 15.9 31.4 313.27499389 4177677 3141 17.1 16.5 415.24 500089 4176058 2876 15.6 43.8 134.15499379 4177643 3118 16.4 24.0 1548.48 500105 4176072 2883 14.3 16.1 15.62499353 4177622 3106 14.4 16.0 459.55 500113 4176090 2883 16.1 23.4 41.76499364 4177587 3081 12.7 15.0 340.39 500117 4176115 2892 18.9 9.4 3.77499358 4177555 3069 11.8 14.6 149.24 500117 4176130 2896 16.7 10.8 23.70499371 4177513 3057 12.7 18.2 44.40 500124 4176152 2881 16.8 32.4 106.14499357 4177481 3053 12.0 14.0 251.83 500132 4176168 2881 20.2 18.2 3.96499364 4177453 3036 13.8 14.5 24.77 500134 4176196 2880 20.6 19.6 23.50499393 4177435 3032 13.8 22.1 64.27 500126 4176222 2886 19.9 19.5 4.73499384 4177405 3021 11.4 19.8 124.66 500126 4176234 2885 19.1 17.3 0.35499393 4177352 3017 11.7 16.0 139.22 500118 4176248 2887 20.2 22.0 4.17499404 4177323 3004 12.6 13.1 2.47 500100 4176260 2881 20.7 14.1 2.95499433 4177280 3001 13.1 19.4 1.13 500084 4176277 2879 20.6 10.6 1.24499477 4177262 3003 13.8 n.m. 3.38 500068 4176276 2886 20.6 59.6 1378.75499510 4177230 3000 13.4 n.m. 1.85 500052 4176286 2890 21.0 44.6 2.37499578 4177219 2996 13.7 n.m. 3.59 500036 4176290 2902 20.0 101.9 17.64499639 4177178 2991 18.6 10.8 9.07 500104 4176288 2923 20.1 79.8 1.18499636 4177125 2983 16.6 10.9 0.71 500124 4176293 2914 24.7 108.9 0.00499672 4177091 2981 17.5 9.8 5.57 500116 4176267 2903 25.7 36.4 1.03499709 4177041 2978 19.9 9.2 1.21 500136 4176239 2876 22.5 17.2 0.54

88 S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

499703 4176989 2972 19.4 10.9 0.00 500151 4176228 2873 24.0 15.8 0.77499712 4176948 2965 18.3 9.3 4.46 500172 4176217 2871 24.6 11.6 9.82499726 4176916 2961 15.9 9.8 2.96 500178 4176209 2863 24.9 10.6 0.00499734 4176863 2957 16.2 11.0 4.60 500187 4176207 2849 25.5 11.6 0.00499443 4177918 3270 5.1 15.7 235.13 500212 4176193 2842 24.5 9.9 0.00499470 4177923 3265 16.9 26.7 308.82 500233 4176196 2821 23.2 10.0 0.00499488 4177916 3270 25.4 34.5 1580.35 500241 4176216 2812 21.1 11.2 0.00499508 4177931 3271 9.3 19.4 932.84 500251 4176210 2819 21.3 12.0 1.62499528 4177940 3270 17.9 28.1 204.35 500248 4176232 2813 21.6 9.9 0.96499544 4177949 3269 10.1 36.3 605.32 500261 4176240 2819 20.4 11.5 0.20499569 4177968 3271 9.1 19.7 1233.62 500279 4176262 2816 20.2 12.3 2.86499586 4177972 3273 8.3 22.7 556.47 500295 4176284 2812 19.9 12.0 2.02499602 4177996 3271 9.6 23.2 894.79 500313 4176299 2802 19.5 11.0 0.00499620 4177999 3274 10.5 72.0 1516.64 500334 4176301 2814 20.8 16.8 7.86499638 4178008 3277 9.5 36.4 1630.48 500357 4176303 2812 19.2 21.3 24.76499652 4178027 3277 9.6 29.3 469.55 500371 4176315 2811 22.2 11.6 0.00499660 4178043 3281 8.2 34.6 928.08 500399 4176329 2809 21.8 10.6 0.00499663 4178060 3283 9.1 29.3 809.68 500422 4176352 2814 23.7 10.5 2.19499675 4178073 3285 11.2 31.3 438.56 500438 4176348 2814 20.4 12.3 0.00499687 4178089 3284 11.9 46.2 1049.72 500456 4176351 2800 19.6 11.9 3.06499704 4178103 3287 10.2 41.5 1337.90 500469 4176352 2805 21.7 11.2 0.00499715 4178119 3284 10.1 31.3 757.83 500483 4176377 2807 19.7 11.7 0.00499721 4178140 3284 9.8 53.5 1327.34 500491 4176389 2803 19.8 12.0 0.00499732 4178159 3286 12.2 35.5 311.13 500522 4176412 2804 19.6 11.9 0.00499740 4178164 3286 11.2 56.7 1718.22 500528 4176420 2805 20.0 12.7 0.00499751 4178170 3281 10.3 24.8 204.63 500533 4176442 2805 19.8 11.3 0.00499759 4178155 3270 15.2 9.9 54.04 500579 4176502 2806 17.7 11.6 0.00499761 4178136 3271 9.5 27.4 133.31 500594 4176517 2811 18.1 11.9 0.00499759 4178115 3263 8.8 22.9 1161.84 500601 4176539 2808 19.2 10.1 0.00499751 4178097 3263 8.1 55.1 1240.30 500611 4176550 2808 19.9 11.6 0.00499752 4178080 3263 11.4 24.4 246.21 500622 4176564 2808 18.5 12.1 0.28499742 4178058 3269 10.6 63.0 797.03 500646 4176586 2810 19.6 12.8 6.54499759 4178050 3264 7.4 46.1 798.44 500659 4176602 2811 19.7 16.0 70.90499750 4178034 3263 8.2 21.1 37.30 500666 4176613 2811 19.6 20.0 157.05499739 4178016 3259 7.7 52.1 1158.85 500685 4176635 2808 18.9 24.6 479.53499729 4178003 3259 8.2 40.4 188.60 500688 4176651 2810 19.6 16.8 1.61499722 4177985 3261 7.8 28.0 178.72 500693 4176666 2813 18.5 12.6 0.17499693 4177964 3257 10.3 29.5 315.47 500699 4176692 2809 17.2 13.9 0.00499708 4177975 3256 11.8 28.4 14.95 500709 4176709 2810 17.6 12.2 0.00499680 4177958 3260 11.7 31.0 87.66 500717 4176731 2813 17.4 11.2 1.54499664 4177961 3264 11.9 65.3 500.75 500725 4176760 2813 17.6 10.5 0.00499676 4177980 3261 10.3 31.1 780.74 500733 4176793 2818 18.2 12.4 0.00499692 4177999 3264 7.7 22.9 203.95 500865 4176755 2752 17.4 10.5 0.00499706 4178007 3268 10.7 39.9 343.51 500858 4176737 2750 17.8 11.3 1.32499712 4178019 3270 11.3 37.6 654.50 500845 4176712 2749 14.8 12.3 0.00499725 4178039 3269 11.7 60.9 1236.71 500843 4176696 2750 16.3 11.0 0.00499726 4178060 3273 9.9 44.7 811.55 500839 4176670 2755 16.0 13.8 0.00499705 4178055 3277 6.8 76.5 1705.48 500827 4176646 2751 15.9 12.1 0.00499632 4177950 3268 11.6 51.9 967.56 500818 4176628 2753 16.3 10.6 0.00499611 4177945 3268 11.8 51.3 668.46 500810 4176611 2753 18.3 11.8 0.00499584 4177942 3264 10.4 49.4 1203.22 500808 4176590 2753 18.8 11.2 0.00499552 4177922 3267 9.4 24.8 1449.72 500805 4176568 2756 18.6 10.9 0.00499519 4177906 3266 8.6 30.9 570.52 500801 4176549 2756 18.4 11.9 4.79499488 4177906 3264 7.2 35.3 332.74 500806 4176524 2750 17.3 17.1 4.04499439 4177896 3247 12.9 32.1 1613.88 500795 4176503 2753 16.6 13.6 0.00499464 4177897 3251 12.1 35.9 5951.23 500799 4176479 2750 16.7 31.6 1368.42499486 4177898 3254 13.7 34.4 49.50 500794 4176458 2749 15.6 15.4 1.19499511 4177917 3256 14.1 31.4 115.63 500799 4176435 2747 15.3 11.2 4.36499512 4177908 3257 11.7 28.1 1961.30 500802 4176409 2747 20.5 18.8 74.05499529 4177923 3258 12.1 29.7 1410.00 500793 4176390 2749 21.9 11.3 0.00499553 4177935 3258 12.8 29.5 21112.71 500793 4176365 2747 17.9 12.7 0.00499560 4177941 3259 10.8 24.8 1369.28 500769 4176359 2749 17.8 12.7 18.12499582 4177953 3261 12.7 34.5 4148.83 500754 4176343 2752 19.6 14.5 0.00499599 4177972 3264 11.3 32.2 2935.26 500732 4176330 2753 19.1 15.1 0.00499620 4177968 3266 10.3 41.9 6295.59 500708 4176327 2753 19.0 14.2 0.00499642 4177979 3267 10.2 36.1 4496.09 500688 4176318 2751 21.1 13.1 2.61499643 4177990 3269 9.9 34.9 1293.60 500673 4176301 2752 21.4 13.4 0.00499663 4178004 3269 11.2 25.6 1467.13 500671 4176291 2721 21.0 14.8 0.00499692 4178021 3269 11.6 26.1 361.29 500641 4176266 2736 20.3 13.6 0.00499697 4178038 3270 11.7 27.1 848.57 500608 4176228 2753 19.7 14.4 0.00499702 4178040 3276 12.3 52.9 19381.27 500595 4176219 2754 18.7 13.6 0.00499718 4178066 3276 12.7 47.3 3839.10 500586 4176194 2754 17.8 15.8 0.00499733 4178057 3274 12.6 34.5 37602.46 500566 4176176 2754 18.1 16.3 0.00

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89S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

499737 4178076 3273 15.9 58.1 250.80 500554 4176155 2758 17.5 14.6 0.00499746 4178101 3273 12.3 52.6 5684.83 500538 4176143 2758 22.8 11.7 0.00499746 4178125 3279 10.9 50.3 6737.34 500521 4176133 2759 22.8 11.7 7.24499712 4177968 3255 12.0 33.0 448.12 500497 4176122 2758 18.4 16.8 0.00499710 4177967 3255 12.3 16.3 32.53 500479 4176115 2758 19.3 16.3 0.00499711 4177946 3252 13.0 10.8 2.18 500462 4176107 2766 19.9 12.4 0.00499637 4177911 3257 13.2 30.1 26.77 500438 4176095 2761 20.0 14.2 0.00499601 4177843 3243 15.1 52.0 472.58 500423 4176074 2759 21.2 14.6 0.00499599 4177844 3231 14.9 29.1 38.07 500403 4176065 2761 19.9 13.4 0.00499611 4177824 3219 17.3 44.9 681.59 500379 4176046 2757 19.7 12.7 0.00499642 4177805 3210 16.2 33.8 27.05 500364 4176030 2758 18.3 16.7 0.00499649 4177792 3202 16.3 47.9 520.65 500346 4176015 2755 17.9 14.9 0.00499666 4177769 3191 16.1 16.9 19.80 500327 4175996 2755 19.7 13.2 0.00499668 4177743 3179 16.1 12.1 57.13 500309 4175982 2758 18.7 12.1 0.00499655 4177726 3167 16.9 11.7 4.85 500306 4175999 2759 19.2 12.3 0.00499659 4177697 3147 16.4 10.7 0.70 500309 4176016 2768 19.2 15.3 2.16499649 4177680 3136 15.8 10.1 0.80 500307 4176036 2768 17.3 14.3 0.00499653 4177637 3123 20.8 10.0 18.47 500310 4176059 2768 17.8 14.8 0.00499641 4177636 3112 16.9 11.3 1.40 500308 4176079 2775 18.3 13.0 0.00499633 4177602 3098 15.1 9.6 0.00 500302 4176100 2780 14.8 18.7 0.00499634 4177568 3089 13.4 11.9 0.00 500292 4176120 2781 16.1 14.7 0.00499654 4177509 3076 11.8 22.2 219.56 500285 4176139 2790 17.5 14.7 0.00499668 4177468 3046 13.1 11.8 78.08 500274 4176145 2788 15.6 14.5 0.00499659 4177433 3034 11.3 38.8 1.23 500266 4176158 2798 13.8 12.5 0.00499729 4177427 3043 11.6 7.2 1.23 500260 4176179 2806 13.3 11.6 0.00499744 4177382 3043 9.7 8.6 51.98 500251 4176191 2814 12.9 11.3 0.00499781 4177362 3041 8.0 8.2 3.95 500598 4175743 2683 20.3 11.4 4.01499790 4177310 3028 7.1 8.0 4.39 500571 4175726 2687 20.5 11.6 0.00499779 4177262 3023 8.4 10.8 1.75 500558 4175725 2683 20.3 12.3 1.54499778 4177219 3013 9.3 8.7 0.73 500537 4175710 2681 20.6 10.6 0.00499785 4177177 3003 9.0 8.9 1.98 500523 4175695 2681 19.6 11.8 0.00499788 4177129 2998 9.4 9.2 0.73 500506 4175693 2689 21.0 11.4 0.00499785 4177065 2991 8.8 8.8 4.38 500486 4175681 2694 21.1 11.4 0.00499769 4177016 2982 8.4 8.4 0.00 500461 4175685 2693 21.9 12.2 0.00499748 4176973 2969 10.7 8.7 3.85 500438 4175686 2688 20.8 11.7 0.00499756 4177988 3147 14.2 35.6 299.87 500416 4175688 2692 20.8 11.9 0.00499779 4177961 3154 11.9 10.4 1.62 500391 4175687 2691 19.1 12.2 0.64499811 4177971 3151 11.9 13.2 3.23 500367 4175691 2692 18.8 12.3 0.00499829 4177997 3154 9.6 13.3 0.00 500346 4175694 2694 18.8 12.6 1.62499831 4178004 3150 9.7 8.2 2.24 500322 4175694 2698 18.6 12.2 0.53499872 4178018 3149 9.2 3.5 0.41 500299 4175689 2694 20.2 12.3 0.00499904 4178026 3138 9.5 3.2 0.41 500278 4175683 2696 19.8 12.6 44.56499937 4178048 3130 11.9 4.3 0.00 500253 4175685 2699 18.8 15.7 20.08499982 4178054 3115 11.5 4.3 1.22 500232 4175680 2698 19.4 14.7 3.43500012 4178059 3110 10.6 5.0 0.00 500213 4175702 2700 19.5 13.4 10.82500042 4178080 3108 10.0 4.7 1.33 500228 4175717 2700 19.6 12.3 5.09500089 4178073 3105 10.9 3.9 1.73 500223 4175736 2704 20.7 13.2 24.99500117 4178082 3105 6.9 2.9 0.52 500221 4175752 2713 21.7 14.9 7.34500141 4178084 3102 8.1 3.8 0.00 500220 4175771 2719 21.1 15.8 145.23500182 4178084 3102 8.4 6.6 8.65 500215 4175791 2720 20.4 14.4 83.54500202 4178079 3097 11.3 10.4 49.58 500210 4175812 2722 21.5 11.2 2.54500241 4178072 3093 10.8 6.2 0.00 500216 4175829 2730 20.3 10.8 0.00500253 4178080 3089 8.3 4.2 2.17 500269 4175663 2692 18.9 15.0 5.37500288 4178053 3083 10.1 12.3 33.15 500274 4175637 2686 18.9 14.2 7.43500304 4178040 3082 12.0 37.3 35.99 500280 4175609 2679 22.3 12.0 5.23500314 4178034 3074 13.4 35.6 76.49 500290 4175586 2671 20.0 14.8 71.25500333 4178027 3070 13.4 33.7 71.14 500298 4175569 2673 18.9 15.0 31.52500347 4177998 3064 13.4 20.9 1.53 500309 4175550 2667 19.3 12.9 3.91500374 4177969 3058 15.6 56.9 0.00 500320 4175528 2663 19.3 12.6 0.00500422 4177957 3035 11.4 14.6 0.93 500333 4175499 2656 19.9 11.1 0.00500452 4177962 3020 9.9 10.0 1.35 500854 4175552 2647 18.9 11.0 0.00500506 4177937 2999 9.6 8.4 3.43 500852 4175533 2642 18.4 15.6 0.86500543 4177950 2978 10.7 5.5 0.00 500846 4175510 2635 20.0 14.1 0.00500595 4177963 2964 11.3 6.5 12.36 500847 4175485 2632 20.1 14.6 0.00500650 4177940 2945 11.3 18.0 33.94 500847 4175457 2622 19.7 11.9 1.13500692 4177954 2921 9.8 21.9 4.72 500841 4175439 2623 18.7 12.1 0.00500718 4178003 2928 9.8 8.6 2.52 500837 4175414 2619 19.1 14.1 1.30500711 4178046 2927 8.7 57.9 155.86 500832 4175390 2612 19.0 12.7 0.72500702 4178088 2937 18.0 71.6 72.77 500823 4175367 2610 18.6 12.1 0.00500686 4178117 2943 10.8 123.0 47.36 500814 4175344 2602 17.1 12.1 0.00500594 4178569 2978 9.5 6.4 1.46 500803 4175321 2601 16.1 12.9 0.00500622 4178593 2970 9.2 4.7 6.27 500795 4175302 2598 16.9 12.5 0.00500650 4178615 2964 10.3 4.9 0.00 500779 4175284 2593 18.5 12.1 0.00500677 4178679 2953 12.1 8.2 6.22 500771 4175261 2587 19.2 12.6 0.00

90 S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

500713 4178685 2944 10.4 8.7 3.45 500764 4175237 2590 18.7 12.6 0.00500726 4178742 2936 11.6 10.6 1.67 500762 4175209 2586 18.9 12.4 0.00500731 4178804 2928 10.9 6.6 0.21 500751 4175192 2582 19.4 12.6 0.96500746 4178842 2916 10.7 2.7 0.42 500749 4175171 2582 23.1 15.3 0.00500783 4178903 2909 14.3 7.5 10.25 500740 4175148 2578 20.9 10.2 0.00500769 4178952 2906 10.4 6.2 0.00 500742 4175124 2578 18.8 14.0 0.00500752 4179010 2904 8.9 4.9 0.00 500739 4175104 2579 18.3 9.2 0.00500752 4179078 2902 9.8 8.6 3.68 500740 4175083 2577 20.5 13.1 0.00500749 4179134 2895 9.7 5.5 0.84 500737 4175060 2577 19.5 13.2 0.00500724 4179183 2891 7.7 5.2 0.00 500739 4175026 2576 17.1 12.9 0.00500702 4179250 2887 8.6 5.5 2.65 500740 4175010 2574 17.2 17.2 2.14500722 4179347 2863 10.1 7.8 0.00 500737 4174984 2570 17.9 12.9 0.42500755 4179451 2844 8.6 5.4 0.24 500734 4174954 2570 18.6 12.7 0.00500841 4179537 2834 9.5 14.6 0.00 500733 4174932 2568 21.3 11.6 0.00500881 4179595 2826 8.7 7.3 0.85 500724 4174908 2568 22.1 13.3 0.64499768 4178507 3314 9.7 15.1 19.22 500711 4174885 2565 21.8 11.8 0.00499785 4178519 3311 9.9 15.8 65.26 500710 4174859 2562 21.1 11.6 0.00499798 4178538 3307 8.1 12.8 4.16 500711 4174838 2562 21.7 12.0 0.00499811 4178565 3302 6.3 10.4 39.02 500714 4174814 2555 21.3 12.2 0.00499780 4178360 3250 6.7 5.8 0.18 500700 4174795 2556 20.2 11.3 0.47499799 4178372 3249 6.4 7.1 0.40 500686 4174774 2556 21.1 12.1 0.00499812 4178378 3251 7.1 7.4 0.39 500677 4174758 2559 21.0 13.6 3.15499835 4178383 3243 7.2 6.7 0.14 500665 4174741 2555 22.5 13.1 2.34499855 4178385 3235 8.2 7.5 0.30 500655 4174717 2551 21.6 26.7 0.00499872 4178391 3231 7.6 10.2 0.67 500631 4174712 2550 19.3 12.0 0.00499892 4178401 3225 7.9 12.9 0.30 500603 4174710 2550 19.7 11.2 0.00499912 4178409 3217 7.1 15.0 20.44 500582 4174705 2552 18.8 10.7 0.00499925 4178423 3213 8.8 27.9 53.25 500558 4174704 2555 19.1 10.8 0.89499934 4178435 3210 6.3 11.4 120.66 500540 4174700 2559 19.2 11.4 0.00499945 4178461 3213 7.8 7.9 0.01 500518 4174694 2561 17.2 13.6 0.32499958 4178485 3213 6.3 11.3 5.22 500501 4174687 2568 18.5 12.1 0.00499960 4178503 3213 5.5 14.6 26.07 500484 4174684 2571 16.9 11.1 0.00499965 4178520 3210 5.8 10.9 5.41 500455 4174678 2566 16.4 12.1 0.00499968 4178544 3210 6.4 10.2 1.77 500443 4174693 2572 18.4 11.8 0.00499990 4178545 3204 5.3 10.1 13.51 500428 4174699 2574 18.3 11.5 0.00500006 4178544 3194 4.9 9.9 23.56 500403 4174698 2588 20.3 13.9 0.00500025 4178547 3185 7.2 10.1 0.01 500369 4174693 2600 19.1 17.8 3.66500036 4178548 3177 14.5 11.4 0.34 500352 4174685 2602 18.2 19.8 42.24500052 4178547 3168 9.6 9.9 1.07 500329 4174680 2603 23.1 14.1 8.87500071 4178546 3157 8.5 11.9 0.01 500302 4174682 2602 21.3 12.1 2.95500091 4178538 3142 13.4 10.0 0.26 500256 4174691 2590 18.4 13.3 0.00500117 4178532 3140 11.8 10.7 0.01 500238 4174686 2589 19.6 11.1 0.82500137 4178535 3134 11.6 5.3 1.40 500236 4174686 2585 19.7 8.9 0.00500157 4178529 3113 11.4 8.6 37.54 500215 4174688 2579 19.8 9.8 0.00500177 4178527 3110 10.7 8.8 16.05 500192 4174678 2570 20.9 9.6 1.20500194 4178516 3101 10.1 12.7 9.92 500162 4174669 2570 20.3 10.1 0.00500213 4178518 3093 11.1 15.1 0.01 500152 4174672 2556 20.8 11.0 0.00500233 4178521 3087 9.6 11.6 1.15 500123 4174672 2546 21.2 10.9 0.00500244 4178532 3076 8.6 13.7 110.79 500208 4174927 2573 19.1 12.6 0.00500261 4178548 3076 7.1 13.3 0.51 500225 4174907 2575 21.1 10.8 0.00500273 4178579 3062 7.4 20.7 5.41 500239 4174891 2574 21.3 11.3 0.00500285 4178597 3059 9.2 13.2 0.01 500254 4174873 2579 20.6 12.5 0.00500295 4178614 3059 7.3 20.4 77.38 500263 4174857 2579 20.8 11.4 0.00500301 4178622 3058 6.9 15.1 227.19 500283 4174851 2580 20.8 9.7 0.00500311 4178638 3056 7.7 18.9 184.78 500302 4174851 2576 19.9 10.9 0.00500328 4178655 3051 8.7 23.0 752.32 500322 4174843 2582 18.7 10.9 0.00500337 4178673 3050 7.7 12.9 11.44 500339 4174836 2591 20.1 11.9 0.00500353 4178690 3051 7.4 10.4 1.04 500352 4174839 2590 18.7 12.1 0.00500367 4178706 3048 7.5 9.1 0.01 500376 4174849 2596 20.9 12.6 0.00500378 4178733 3051 7.6 9.1 316.64 500391 4174849 2603 21.1 15.1 1.37500383 4178752 3046 7.7 8.9 153.35 500404 4174856 2600 19.8 16.1 1.79500394 4178769 3043 8.2 10.6 102.41 500423 4174864 2609 20.4 15.9 0.00500402 4178793 3044 7.7 10.8 3.44 500449 4174866 2611 21.7 18.7 0.00500407 4178819 3044 9.1 11.6 0.01 500470 4174871 2606 22.0 16.0 0.00500411 4178837 3044 9.4 7.8 0.58 500482 4174879 2607 23.0 14.6 0.00500418 4178861 3042 9.1 7.6 0.12 500500 4174884 2605 22.4 17.2 0.00500427 4178881 3036 9.3 8.5 0.57 500517 4174892 2604 23.0 15.7 0.00500435 4178905 3033 9.1 8.3 0.54 500535 4174905 2607 22.6 12.2 0.00500440 4178925 3028 10.4 6.6 0.01 500551 4174926 2606 20.3 14.5 0.00500444 4178944 3027 8.3 6.5 0.37 500568 4174939 2605 18.3 14.1 0.00500445 4178966 3024 10.9 2.3 0.15 500600 4174933 2594 17.1 12.6 0.00500441 4178998 3023 11.9 3.8 0.01 500625 4174934 2595 16.2 13.6 0.00500448 4179031 3021 10.2 6.4 2.06 500647 4174939 2586 16.3 13.3 0.00

(continued on next page)

91S. Giammanco et al. / Journal of Volcanology and Geothermal Research 311 (2016) 79–98

Table 1 (continued)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

Latitude UTM Longitude UTM Altitude(m a.s.l.)

Air temp(°C)

Soil temp(°C)

Soil CO2 efflux(g m−2 d−1)

500448 4179031 3019 7.8 8.1 1.33 500667 4174928 2579 19.8 14.7 0.00500455 4179062 3019 8.1 7.2 0.01 500686 4174937 2579 19.2 13.9 0.00500456 4179092 3013 8.8 6.4 0.01 500708 4174933 2576 23.3 13.3 0.00500436 4179142 3013 7.0 5.4 0.01 500440 4174782 2602 21.6 68.1 9267.64499863 4176777 2940 16.8 8.1 0.20 500456 4174773 2600 21.6 31.3 93.93499893 4176759 2934 19.9 7.9 0.12 500476 4174786 2598 20.8 19.6 6.81499909 4176761 2933 21.3 9.1 0.00 500461 4174799 2594 20.9 40.5 39.08499927 4176748 2927 17.4 8.9 0.38 500451 4174800 2595 19.4 69.1 514.03499953 4176738 2926 13.3 7.1 0.15 500465 4174786 2597 20.1 20.5 0.00499971 4176733 2926 14.7 8.6 0.23 500207 4176531 2895 17.1 7.7 0.00499993 4176732 2925 14.7 7.9 0.18 500228 4176526 2891 20.4 8.2 0.00500014 4176720 2923 14.2 8.3 0.55 500257 4176509 2893 21.2 9.1 0.48500035 4176706 2921 15.9 11.1 0.45 500269 4176487 2877 24.1 9.8 0.72500051 4176688 2920 10.5 16.5 0.13 500274 4176458 2873 24.3 9 0.48500064 4176687 2922 17.2 35.6 506.19 500276 4176429 2870 23.3 8.6 0.00500071 4176698 2922 19.6 36.2 1115.98 500275 4176400 2862 21.7 9.9 0.48500088 4176692 2927 19.3 39.7 136.23 500295 4176392 2850 22.4 8.8 0.00500106 4176687 2934 17.0 48.5 717.76 500322 4176414 2847 24.3 10.4 0.24500131 4176686 2949 15.9 47.5 796.42 500346 4176432 2844 19.8 10 0.00500134 4176697 2921 16.4 22.4 0.00 500368 4176453 2840 18.8 10.2 0.00500145 4176707 2915 16.4 22.4 0.00 500387 4176473 2841 21.2 11.3 0.00500174 4176692 2908 15.6 13.9 0.00 500428 4176507 2835 20.7 10.7 0.48500173 4176704 2901 17.1 17.5 0.28 500450 4176529 2832 23.2 11.2 0.00500198 4176701 2905 16.8 12.5 0.10 500471 4176547 2833 22.6 10.6 0.00500214 4176702 2907 15.4 10.1 0.00 500493 4176564 2833 24.2 10.8 0.00500226 4176696 2910 14.3 10.6 0.26 500523 4176569 2833 23.2 11.9 0.00500244 4176696 2910 14.5 10.1 0.13 500541 4176590 2832 21.5 10.6 0.00500257 4176710 2888 15.0 8.9 0.00 500558 4176610 2833 20.9 10.2 1.68500278 4176709 2890 15.2 11.3 0.00 500589 4176610 2825 19.2 11.3 0.00500298 4176715 2889 15.3 11.3 0.00 500620 4176618 2819 19.6 11.6 270.48500314 4176731 2889 15.2 16.3 0.10 500653 4176625 2815 21.3 27.2 972.72500327 4176742 2889 15.3 12.4 0.00 500560 4176102 2741 19.4 11.9 0.00500346 4176759 2890 13.7 11.4 0.03 500587 4176105 2740 19.7 12.2 0.00500359 4176768 2889 13.8 11.2 0.00 500617 4176110 2734 18.4 11.8 0.48500378 4176767 2883 13.1 11.1 0.11 500648 4176110 2730 17.8 11.8 0.00500402 4176767 2879 12.4 9.3 0.12 500680 4176110 2732 21.2 10.7 0.00500418 4176773 2876 12.5 9.9 0.23 500711 4176114 2720 20.8 10.4 0.00500440 4176779 2871 12.4 13.9 13.51 500741 4176119 2714 17.1 11.3 0.00500462 4176796 2873 12.3 12.7 9.31 500770 4176126 2715 20.4 10.8 0.00500480 4176806 2871 11.6 13.6 23.17 500801 4176125 2715 20 10.8 0.48500497 4176819 2869 12.9 13.2 0.17 500829 4176129 2712 20.1 10.7 0.00500517 4176836 2871 12.6 16.1 0.10 500859 4176139 2712 20.2 10.4 0.00500537 4176828 2864 12.9 21.3 152.18 500865 4176171 2713 18.6 15.5 1.44500554 4176829 2864 13.6 19.6 18.29 500852 4176194 2715 17.2 11.9 0.24500574 4176836 2857 20.1 10.5 16.87 500855 4176221 2717 22.6 11.1 0.24500596 4176844 2854 18.2 13.2 77.32 500848 4176243 2720 21.4 12 0.00500614 4176855 2852 15.6 12.9 16.22 500840 4176268 2724 18.1 10.3 0.00500632 4176864 2852 15.7 12.2 90.55 500837 4176292 2723 16.2 11 0.48500653 4176879 2853 15.6 11.9 0.00 500827 4176313 2728 16.8 10.2 0.72500665 4176901 2854 16.2 12.2 0.16 500818 4176333 2733 18.2 12.1 0.00500678 4176919 2853 15.6 11.1 0.04 500807 4176345 2739 22.3 11 0.00500693 4176933 2851 13.1 13.0 0.37 500866 4176110 2708 21.7 8.7 0.00500712 4176947 2854 14.3 9.8 0.15 500872 4176082 2710 19.8 87 0.00500736 4176970 2848 13.1 10.9 0.00 500873 4176053 2707 19.8 10.1 0.48500749 4176974 2849 12.3 12.3 0.16 500865 4176025 2704 22.7 10 0.00500740 4176944 2845 17.3 13.0 0.00500733 4176923 2846 14.8 13.3 0.13500712 4176916 2840 13.4 12.5 0.15500702 4176902 2845 14.3 13.8 0.00500686 4176885 2844 13.0 13.8 0.53500674 4176870 2849 13.0 12.8 0.00500647 4176853 2848 12.6 25.6 15.65500631 4176836 2848 14.7 16.8 14.14

n.m. = not measured.

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volcano and they preceded increases in the volcanic activity of Mt. Etna(Alparone et al., 2004; Pecoraino and Giammanco, 2005).

Other areaswere characterized by anomalies in soil CO2 effluxwith-out anomalies of soil temperature, such as a wide area just SSW of thesummit craters, a large part of the NE cone that includes some fissures

on its NE and NW sides, a small area just SE of the 2002–2003 conesat altitude of about 2600 m a.s.l. between the 2001 and 2002–2003eruptive fissures, and finally some other small areas located north ofthe NE crater close to the ancient rim of the Cratere del Piano caldera(Fig. 4).

Fig. 2. a) Histogram of distribution of log-values of soil CO2 efflux; b) logarithmicprobability plots of soil CO2 effluxes at the study area. Original data are shown withblack dots. Statistically distinct populations are highlighted with roman numbers in eachplot (population I is not shown because it includes values lower than 0.01 g m−2 d−1),and the respective partitioned populations are indicated with straight lines throughcalculated points.

Fig. 3. a) Histogram of distribution of log-values of soil temperature; b) logarithmicprobability plots of soil temperature values at the study area. Original data are shownwith black dots. Statistically distinct populations are highlighted in each plot withroman numbers, and the respective partitioned populations are indicated with straightlines through calculated points.

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4. Interpretation of data

The spatial distribution of soil CO2 and soil temperature values high-lights a close connection between volcano-tectonic features in the Etnasummit region and anomalies in both surveyed parameters (Figs. 4 and5). This underlines the role of high-permeability pathways produced byrock fracturingdue to volcano-tectonic stress in the release of importantamounts of mass and energy by diffuse magmatic degassing. In particu-lar, the largest areas of CO2 release, apart from the 2008–2009 fissurethrough which magma was being emitted at the time of our survey,were those encircling the summit cones and the zone located just

south of the BN. Occurrence of diffuse degassing through large parts ofrelatively old eruptive fissures (e.g., TdF area, 1991, 2001, 2002, 2004,2006, 2011, 2012 and 2013 fissures) and part of old caldera rims(Fig. 4), implies that those volcano-tectonic structures still act asdegassing pathways from an active magmatic source of gas (most likelythe main feeder conduits of the volcano).

By plotting the log values of CO2 efflux versus the corresponding soiltemperature values (Fig. 6), three different types of correlation can beobserved. In general, an approximate positive correlationwas found be-tween the two parameters. However, most of the measured pointsshowed a poorer correlation, with highly variable CO2 effluxes at rela-tively low temperature (i.e., b20 °C) (area marked with A in the Fig. 6plot). This group represents sites with diffuse degassing anomalies atrelatively low temperature, a phenomenon that occurs where high-

Fig. 4.Map of the distribution of soil CO2 efflux values in the studied area. Also shown are the location of sampling points (black dots) and the known volcano-tectonic features (red lines:eruptive or dry fissures; dashed lines: caldera rims). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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enthalpy fluids rise towards the surface, condensate at relatively greatdepth and lose heat during ascent of vapor, so as to produce only“cold” degassing at the surface (sub-fumarolic zones, as described inAubert, 1999). In physical terms, this kind of degassing at active volca-noes is closely related to low flow of water vapor within fractures andfaults that are not well developed and possibly do not reach the surface.Under these conditions, the pressure driving fluid convection thusdrops considerably before reaching the soil-atmosphere boundary. Asa consequence, ascending gas is dispersed laterally over large areas, par-ticularly if ground permeability is generally high as on Mt. Etna. A sec-ond group of measurement points showed a more significant positivecorrelation with high values of both parameters (area B in the Fig. 6plot). This group describes degassing conditions that are typical of con-vective fluids flowing through well-developed fractures that reach thesurface (fumarolic zones stricto sensu, Aubert, 1999). These high-enthalpy fluids condense at the soil-atmosphere boundary and carrylarge amounts of CO2 and heat. Lastly, a third group of measurementpoints showed a similar pattern as that of the second group, butwith re-markably lower CO2 effluxes (or even with no CO2 emission at all) andhigher maximum temperature values (area marked C in the Fig. 6plot). This group denotes degassing conditions where rising fluids

carry less CO2 and more heat than at sites belonging to the secondgroup. This is the case of sites near high-temperature fumaroles(T N 90 °C), where the emitted gas is rich inwater vapor andmoderatelyenriched in CO2 due to relative dilution of incondensable gases, or ofsites characterized by residual degassing near old eruptive vents (likeon the rim of the 2002–2003 cones), where the emitted gas is stillwarm but depleted in CO2.

5. Tectonic model of Mt. Etna's summit from soil degassing

The analysis of the collected geochemical data broadens the infor-mation from existing structural data and enables drawing a more com-plete picture of the tectonic scenario in the summit area ofMt. Etna. Thelargest heat andmass transfer rate occurred from all the fractured areasalong the rims of themain summit craters— an indication of their closeassociation with the main volcanic conduits. The very high ground per-meability that produces such an efficient heat and mass release wouldalso indicate highly unstable structural conditions near crater rims. Con-versely, not all the knownvolcano-tectonic structures that develop fromEtna's summit cone down to lower altitudes are associated with soildegassing or thermal anomalies. This would imply that only some of

Fig. 5.Map of the distribution of soil temperature values in the studied area. Also shown are the location of sampling points (black dots) and the known volcano-tectonic features (redlines: eruptive or dry fissures; dashed lines: caldera rims). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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them are permeable enough to allow gas leakage from deeper zones ofmagma storage and/or are affected by active circulation of hydrother-mal fluids. Among the few degassing structures around the summitcone, those most active are the 1991, 2001, 2002, 2006 and 2007 erup-tive fissures on the southern zone of the study area and the southernflanks of Southeast Crater and Bocca Nuova. Those areas are locatedalong the supposed detachment lines that delimit the eastward- andsouthward-collapsing sectors ofMt. Etna, due to gravitational spreadingof the volcano (Solaro et al., 2010; Bonforte et al., 2011; Ruch et al.,2012; Acocella et al., 2013). They should therefore be taken into consid-eration as possible sites of future magma intrusion and eruption (Neriand Acocella, 2006; Falsaperla and Neri, 2015).

Some other surveyed areas show diffuse degassing withoutvisible surface fracturing. In detail, areas characterized both byanomalous soil temperature and by anomalous CO2 efflux can beinterpreted as the surface expression of shallow hydrothermal sys-tems that have developed along recently buried fractures, e.g. the

southern flank of the Bocca Nuova cone, where several eruptive fis-sures opened during the last century (Behncke et al., 2004, 2005;Neri et al., 2011a).

Areas characterized by cold degassing, namely by anomalous CO2

degassing without anomalies in soil temperature, can be associatedwith sub-fumarolic zones (Aubert, 1999) and therefore release CO2

through fractures that were possibly still in the process of developingand expanding. If this is true, at least someof these fracturesmay poten-tially extend towards the surface in the future to become fumaroliczones. Among these, one deserving particular attention is located justeast and southeast of the 2002–2003 cones, in the southern part of thestudy area (Fig. 4). In this area, anomalous CO2 degassing is distributedfollowing the supposed prolongation of the Torre del Filosofo (TdF) frac-tures towards the south, parallel to the 2002 fissure and in part runningacross the east flank of the huge 2002–2003 pyroclastic cones. Such adegassing is likely not related to residual gas emissions from the cooling2002–2003 magmatic body; as already suggested by Pecoraino and

Fig. 6. Correlation plot of soil CO2 effluxes (in log values) vs. the respective soiltemperature values measured in the study area. Three groups of values (marked withletters) can be observed, according to their different behavior (see text for explanation).The vertical red dashed line indicates the boiling point of water at the average altitudeof 2800 m a.s.l. (For interpretation of the references to color in this figure legend, thereader is referred to the web version of this article.)

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Giammanco (2005) based on geochemical evidence, new magma wasintruded within the upper portions of the volcanic feeder system afterthe end of that eruption, so the opening of new degassing fractures inthe same area could be possible. This hypothesis is also supported byAlparone et al. (2005) and Neri et al. (2006), who highlighted the rela-tionship between the radon gas emission from soil in the TdF area andthe eruptive activity of the summit craters (particularly the SoutheastCrater), suggesting the existence of a near-direct structural link be-tween the TdF fractures and the complex central conduit of the volcano.

In other cases, cold degassing areas correspond to ancient caldera orcrater rims, which therefore act as important and deep zones of passiverelease ofmagmatic gas. One important feature in the distribution of soilCO2 efflux values is the possible recognition of a buried caldera rim thatruns around the summit cone at an altitude over 3000 m a.s.l. (Fig. 4).This rim is probably the final result of coalescent calderas formed byseveral huge summit collapses that occurred during the 122 B.C. erup-tion and during those in 1444, 1169, 1537 and 1669 (Chester et al.,1985; Calvari and Pinkerton, 2002). The 1669 eruption was the largestin the last 2000 years in terms of volumes of lava and tephra eruptedand one of the most violent in terms of energy released (Wadge et al.,1975; Corsaro et al., 1996; Tanguy et al., 2007). It lasted from March11 to May 11, 1669, during which a large part of the summit cone ofMt. Etna collapsed on March 25 as a consequence of a violent explosiveevent (Corsaro et al., 1996). Eruptive activity after 1669 filled the calde-ra with lava and tephra and nomore traces of it remained visible on thesurface (Chester et al., 1985; Hughes et al., 1990).

A schematic model that describes the association between varioustypes of diffuse degassing and the structural framework of the summitof Mt. Etna is shown in Fig. 7.

6. Possible future implications and conclusions

The data obtained from this survey havemany implications for a bet-ter understanding of the possible development of Etna's summit

morphology, structural framework and volcanic activity. Several faults,fractures and old caldera/crater rims are still active pathways for theleakage and surface release of magmatic/hydrothermal fluids, thusplaying a possible active role also in enabling magma to intrude anderupt at the surface. This is testified, for example, by the periodic re-opening (e.g., 1910, 1918, 1942, 1971, 1983, 1985, 1989, 1991, 2001,2002) of the fissure system that starts from the summit craters andruns southward along the central part of the studied area to then devel-op as the S Rift at a lower altitude on the volcano. It is evident that thissystemhas developed along amajorweak zone in the volcano structure,so the probability that future eruptionsmay occur along these structurallineaments is higher than in other areas of the volcano (Cappello et al.,2012; Del Negro et al., 2013). According to this interpretation, the like-lihood of new eruptions is even higher in the areas where the mainvolcano-tectonic lines belonging to the S Rift cross ancient calderarims that are subject to active degassing, such as the Ellittico and Crateredel Piano calderas, since these points are among the weakest parts ofthe summit volcanic structure. It is probably no accident that smallparasitic vents near the summit craters of Mt. Etna have recentlyopened along a belt that runs around them at an altitude of about3000m a.s.l. Examples are the main vents of the 1999 eruption locat-ed at the southeast base of the SEC cone (Calvari et al., 1999); the“Sudestino” spatter cone (opened at the southern foot of the SEC)that was active from 2000 to 2001 (Behncke et al., 2008); theupper hornitos and cones that formed during the early stage of the2001 eruption (Acocella and Neri, 2003); upper vents of the 2004–2005 eruption (Neri and Acocella, 2006); the numerous eruptive fis-sures opened at the eastern base of the SEC and at the southern baseof the BN in 2006–2007 (Bencke et al., 2008), and finally the buildingof the New Southeast Crater on the lower eastern flank of the SEC(Vicari et al., 2011; Ganci et al., 2012; Falsaperla and Neri, 2015).

The wide area of “cold” degassing (i.e. with anomalous CO2 emis-sions not associatedwith soil temperature anomalies) found just south-west of the BN crater may well be considered an area where futureopening of fractures or eruptive fissures is possible, due to tectonicstress related to the progressive backward sliding of the summit areaof the volcano following gravitational spreading of Etna east flank,though it is less likely than along the S Rift. This is also reflected in thefewer eruptive fissures that opened in this part of the summit area dur-ing the recent past (e.g., 1949, 1964, 2006, 2007; Behncke et al., 2005,2008). In conclusion, the combined use of soil CO2 effluxmeasurementsand soil temperature measurements has proved useful to detect hid-den/buried faults. The methods are relatively easy and fast to performin the field and allow acquiring a large number of data that can be im-mediately processed. Analyzed data can be used efficiently to developgeochemical models that help understanding the structural frameworkof a volcanic area. In the specific case of Mt. Etna, soil gas data can helpdetecting volcano-tectonic structures that may act as future pathwaysfor the intrusion or eruption of magma at the surface, as they are cur-rently sites of magmatic gas leakage.

Acknowledgments

This work was partially funded by the project CGL2005-07509/CLI,Ministry of Education and Science of Spain, by the Cabildo Insular de Te-nerife, Spain, by DPC-INGV project FLANK and by Istituto Nazionale diGeofisica e Vulcanologia — Osservatorio Etneo, Sezione di Catania. Weare grateful to Amy Donovan, Jezabel Maldonado and RuymanHernández for helping during the field work. We also thank the Parcodell'Etna, in particular Salvatore Caffo, and the Corpo Forestale dellaRegione Siciliana, for authorizing us to work inside the protected areasof Mt. Etna and Stephen Conway for revising the use of English in thismanuscript. Finally, we thank G. Groppelli for his careful and useful re-view of the manuscript and L. Wilson for the editorial handling of thepaper.

Fig. 7. Schematic structural model of the summit of Mt. Etna, showing the main morpho-volcanic features of the area (summit craters indicated with BN-VOR for Bocca Nuova-Voragine,NEC forNortheast Crater, SEC for Southeast Crater; Cratere del Piano indicates an old crater rim), aswell as the interpretation to soil gas data acquiredduring thepresent investigation.Darkred branches indicate magma intrusions at relatively shallow depth (vertical dimension not to scale). The dashed red line indicates the hypothetical pattern of the isotherm of groundtemperature corresponding to the boiling point of water (about 90 °C) at the local conditions of external pressure. Light red areas indicate zones of “hot” degassing (detected at thesurface as anomalies in soil temperature with minor CO2 contribution), caused mostly by steam emission; yellow area indicate zones of “warm” degassing, detected at the surface asanomalies both in soil temperature and in soil CO2 efflux); lastly, blue areas indicate zones of “cold” degassing, detected at the surface as anomalies in soil CO2 efflux not associatedwith thermal anomalies. See text for further details. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

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