Etna Area Research Articles

Identifying wine grape aromatic maturity using e-nose and GC-MS: the case of Nerello Mascalese grapes from two contrade of the Etna area

A study of aromatic maturity of Nerello Mascalese grapes from two districts (“Contrade”) of the Etna area was carried out using gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose). To validate our hypothesis regarding the potential use of E-nose for aromatic maturity, two vineyards with different characteristics (08 Alto and Solicchiata) were used. Grapes were sampled at 18°, 21° and 23°Brix. Regarding the phenol maturity index, total anthocyanins reached a peak at the second sampling in 08 Alto grapes, while in Solicchiata they constantly increased. The ratio total anthocyanins: total polyphenols in 08 Alto grapes increased from 0.14 to 0.33, and in Solicchiata from 0.17 to 0.23. As regards grape volatile organic compounds (GVOCs) for the aromatic maturity index, in Solicchiata the concentrations of glycosylated benzenoids and C13-norisoprenoids were much higher than in 08 Alto, and the concentration decreased during maturity (opposite trend to the anthocyanins); by contrast, in 08 Alto, concentrations peaked at the second sampling time (as with the anthocyanins). The E-nose results did not completely coincide with the GVOCs pattern, but they discriminated the maturity stages very well. However, the different metallo-porphyrins responded differently depending on the class of GVOCs, highlighting very promising results in terms of GVOCs non-destructive prediction by means of principal component regression (PCR) application. E-nose shows potential for easy use with rapid PCR for the monitoring of the aromatic maturity of Nerello Mascalese grapes.

Depth and Spatial Variation of the Shear Wave Attenuation Parameters in the Shallow Crust and Lower Crust/Upper Mantle of Mt. Etna (Italy)

AbstractSeismic wave attenuation is a key feature of seismic wave propagation that provides constraints on the composition and physical state of the medium within the Earth. We separated intrinsic and scattering attenuation coefficients for the shallow crust and lower crust/upper mantle in the Mt. Etna area. For this purpose, the Multiple Lapse Time Window Analysis (MLTWA) was applied to two groups of earthquakes, well separated in depth. We also studied the spatial variation of the attenuation parameters by dividing the study area into four sectors around Etna. The results show an effective homogeneity of the propagation characteristics inside Etna and, in particular, some lateral variations and minor variations with depth. We observe that structural discontinuities and lithology control scattering losses at all frequencies, with higher scattering in the shallow crust. The intrinsic absorption shows no sensitivity to the presence of these main geological structures and is quite uniform for different depths. Furthermore, compared to the northern sector of the volcano, the southern one shows stronger scattering attenuation at low frequencies. This pattern correlates well with the high seismic activity along most of Etna’s active tectonic structures and ascending magmatic fluids that characterize this sector of the volcano. Although we only discuss the differences in the "average" scattering and inelastic properties of the investigated volumes, the results of this study are very informative about the characteristics of each region. Moreover, they suggest that a future study is necessary, providing a more detailed picture of the spatial distribution of seismic attenuation in the study area, through a 3D inversion of the attenuation parameters estimated along the single source-receiver paths.

Moment magnitude for earthquakes in the Etna volcano area

SUMMARYAccurate quantification of seismic activity in volcanic regions is an important asset for improving hazard and risk assessment. This is especially true for densely populated areas, as in the case of Etna volcano (Southern Italy). There, the volcanic hazard is amplified by the seismic risk of active faults, especially on the eastern flank of the volcano. In such a context, it is common to rely on moment magnitude (MW) to characterize seismicity and monitor the energy released during an eruption. In this study, we calculate the moment-based magnitude (MW) for selected seismic data sets, using different approaches in distinct magnitude ranges to cover the widest possible range of magnitude that characterizes Etna's seismicity. Specifically, we computed the MW from a data set of moment tensor solutions of earthquakes that occurred in the magnitude range 3.4 ≤ ML ≤ 4.8 during 2005–2020; we created a data set of seismic moment and associated MW for earthquakes 1.0 ≤ ML < 3.4 obtained by analysing source spectra; we fine-tuned two relationships, for shallow and deep earthquakes, to obtain MW from response spectra. Finally, we calibrated a specific relationship between MW and ML for the Etna area earthquakes in the range 1.0 ≤ ML ≤ 4.8. All the empirical relationships obtained in this study can be applied in real-time analysis of the seismicity to provide fast and robust information on the released seismic energy.

Impact of the Different Grid Resolutions of the WRF Model for the Forecasting of the Flood Event of 15 July 2020 in Palermo (Italy)

One of the most important challenges in atmospheric science and, in particular, in numerical weather predictions (NWP), is to forecast extreme weather events. These events affect very localized areas in space, recording high pluviometric accumulations in short time intervals. In this context, with the present study, we aim to analyze the extreme meteorological event that occurred in the northwestern and eastern parts of Sicily on 15 July 2020, by using the weather research and forecasting (WRF) model. In particular, during the afternoon, several storms affected those areas, causing intense precipitation, with maximum rainfall concentrated on the city of Palermo and in the Etna area. The rainfall at the end of the event reached 134 mm in Palermo and 49 mm in Catania, recorded by the Sicilian network meteorological stations. Because the event at Palermo was strongly localized, the analyses have been carried out by employing different sets of numerical simulations, by means of the WRF model, with horizontal spatial grid resolutions of 9, 3, and 1 km. Furthermore, the output of the performed simulation has been used to assess the thermodynamic profile and atmospheric instability indices. It allowed us to check the adopted parameters against those usually implemented in the flash flood scenario. By using the finest grid resolutions (3 and 1 km), the WRF model was able to provide more accurate predictions of the rainfall accumulation, even if they were strongly localized. Conversely, the implementation of less-refined spatial domain (9 km) did not allow us to obtain predictive estimates of precipitation.

Earthquake-resistant Techniques in the Etna Area (Sicily) after the Earthquake of 1818

ABSTRACT The purpose of this paper is to offer a contribution to the topic of earthquake-resistant construction techniques in Sicily in the nineteenth century, with particular reference to the building systems used after the earthquake that hit the Etna area between 20 February and 1 March 1818. Our research is based on an overlapping study of the bibliographic sources and archive documentation supported by direct analysis of the buildings. The aim is to delve into the building techniques used in the reconstruction by analysing a series of significant case studies. After examining the effects of the 1818 earthquake in the Etna area and its influence on the local technical culture, attention was placed on the systems used to reinforce and restore the buildings, highlighting some important innovations in determining anti-seismic project criteria aimed at decreasing the seismic vulnerability of buildings.

Effect of atmospheric exposure on alkali activated binders and mortars from Mt. Etna volcanic precursors

Volcanic pyroclastic residues from Mt. Etna have been recently used to produce alkali activated materials to be employed in the restoration of the ancient buildings of the Etnean area. With the aim of preliminarily testing the durability of these products, binders and mortars have been exposed outdoors for six months. The characterization was achieved by a multi-analytical approach to determine the effect of the weathering; variations were evaluated in terms of composition, mechanical properties, dynamic vapour sorption, and visual aspect before and after exposure. The results show that both alkali activated binders and mortars are barely affected by atmospheric exposure.

3-D Q-coda attenuation structure at Mt. Etna (Italy)

Summary Three dimensional attenuation images of Mt. Etna volcano obtained by the analysis of Q-coda from local volcano-tectonic earthquakes are presented in this work. Seismic sources are confined inside the Etna structure with a maximum focal depth of 35 km below the sea level. The space distribution of the attenuation values was calculated by using 3-D weighting functions derived by the sensitivity kernels of Pacheco and Snieders (2006) and approximated by a polynomial interpolation, represented in the maps by using a back- projection method. Data were analyzed in four bands with central frequency placed at 1.5, 3, 6 and 12 Hz respectively. We observed a frequency dependence of Q-coda with values that range from 55 at 1.5 Hz to 218 at 12 Hz. Q-coda space distribution in the Etna area shows almost uniformity in the average attenuation in the first 35 km below the surface. The images were derived with a resolution of 5 km. We observe as one of our main conclusions that Q-coda attenuation space anomalies are correlated with the areas of highest structural heterogeneities and are distributed along the well-known tectonic structures which characterize the crust in Mt. Etna region. Previous and numerous velocity and attenuation images describing the structure of Mt. Etna support our main conclusion: high Q-coda volumes almost coincide with the zones marked by high velocity and relative low total attenuation for direct waves.

Mid-Term Effects of Conservative Soil Management and Fruit-Zone Early Leaf Removal Treatments on the Performance of Nerello Mascalese (Vitis vinifera L.) Grapes on Mount Etna (Southern Italy)

The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with early leaf removal (ELR) on the performance of the black grapevine variety Nerello Mascalese (Vitis vinifera L.). The research was carried out from 2015 to 2018 in a vineyard located in the Mount Etna area, East Sicily, Southern Italy. An average of about 8000 cm2 of leaves were removed from the ELR vines, corresponding to a canopy defoliation of 44% in 2017 and 30% in 2018. As for the stem water potential of both primary and lateral leaves, ELR-MT treatment showed the best performance (up to −0.4 MPa) among the four combinations. In 2017, no differences in yield/vine were found among treatments, whereas in 2018 the yield was significantly lower in ELR treatments. Among the different treatments performed, the ELR-MT showed the best results both in terms of physiological plant parameters (water status and photosynthetic activity) and fruit quality (higher concentration of sugars and total anthocyanins and polyphenols). ELR-MT treatment is also associated with a lower incidence of tillage operations from four to only one per year (−60–70 h/ha). In contrast to what was observed in the first 3 years of application (i.e., from 2015 to 2017), yield was heavily penalized during the fourth year of application (2018), probably due to the excessive depletion of nutritional reserves, the reduction of bud fertility and the unfavorable meteorological condition. For these reasons, the ELR-MT combination might require an interruption every 2–3 years of application.

Analysis of Mount Etna’s volcanic rocks

Abstract In this work we have analysed the basalt rocks from the area of Mount Etna using 57Fe Mössbauer spectroscopy (MS), X-ray diffraction (XRD) and X-ray fluorescence analysis (XRF). Mössbauer spectroscopy was used to identify and to quantify the content and the magnetic nature of the iron-bearing minerals in the lava samples. Magnetite, olivine, pyroxene, hornblende, hematite and goethite of different relative abundances were found in the investigated samples. X-ray diffraction supported the structural analysis and determined the phases not visible by MS, like albite and calcite. X-ray fluorescence was employed to provide compositional analysis of the studied samples. The used methods showed qualitatively similar composition of the investigated rock samples, even though they also disclosed the quantitative differences in phase proportions agreeing with observed sample coloration. Identified compositional variations may result from the different processes during basalt formation and/or unequal weathering history.

FT-IR study of early stages of alkali activated materials based on pyroclastic deposits (Mt. Etna, Sicily, Italy) using two different alkaline solutions

The huge availability of volcanic deposits in Mt. Etna volcano and the wide use of volcanic materials as aggregates in local architecture encouraged us to apply them in alkaline environment to produce geopolymeric binders to restore historical buildings of Mt. Etna area. Two clusters of samples for each volcanic precursor (volcanic ash and ghiara paleo-soil) were produced, using 10 and 20% wt. of metakaolin and two different alkaline solutions based on sodium and potassium respectively. A comparative study was made in relation to activators used, focusing on evaluation of polycondensation step (in ATR); chemical and structural characterization (FT-IR); TGA analysis, qualitative XRD analysis and mechanical compressive test after 7 and 21 curing days. ATR results confirmed the occurrence of geopolymerization for all samples; FT-IR analysis showed a higher content of carbonates in potassium-samples, decreasing at increasing of metakaolin content. A low weight lost was recorded in consolidated samples, as well as a partial dissolution of volcanic phases. Higher mechanical compressive strengths for K-samples, reaching 89 MPa as highest value after 21 days, differently to sodium-samples (51 MPa) were recorded, reflecting the porosity of the different specimens.

Can volcanic trace elements facilitate Covid-19 diffusion? A hypothesis stemming from the Mount Etna area, Sicily

In December 2019, severe cases of pneumonia of unknown aetiology were reported in Wuhan city, in China. Lately, the pneumonia was related to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and the diseases was termed coronavirus disease-2019 (COVID-19). At the end of January 2020, the infection spread all over Italy, but with high infection rates and mortality in the northern part, especially in Lombardy, the most industrialized and polluted region of the country. It is noteworthy that a strong association between severe viral respiratory disease and air pollution has been described. Air pollutant could be solid particles, liquid droplets, or gases and can be of natural origin (such as ash from a volcanic eruption) or released from motor vehicle depletes (carbon monoxide gas) or factories (sulfur dioxide). Volcanic eruptions release large amounts of sulphuric acid, hydrogen sulfide, and hydrochloric acid into the atmosphere. Pulmunary diseases spreadby means of small droplets in thebreath, also called aerosols, and air pollution may facilitate the outside survival of viruses. We suppose that ash and gases emitted from the Mount Etna contributed to air pollution, potentially favouring the major contagion of COVID-19 in the eastern flank of the mountain, as in Catania city. In fact, ash and gases (with regard to radon) are usually particularly intense in winter, with a reduction of emission of specific metals with warmer weather. This is the first paper that elaborates the hypothesis of a potential role of volcanic gases and heavy metals-related air pollution, combined to specific climatic conditions and regional topography, in favouring severe COVID-19 diffusion in Sicily. Clinical and epidemiological studies are needed to support the hypothesis and plan the due prevention and awareness-raising campaigns.

A ground motion model for volcanic areas in Italy

In Italy, earthquakes caused by volcanoes are of primary importance in the evaluation of seismic hazard, since several volcanoes seriously endanger densely populated areas (e.g. Catania and surroundings, Campi Flegrei, Vesuvius). On the other hand, there are very few models for the prediction of ground motion induced by volcanic events, mostly because observations are scarce and volcanic earthquakes less frequent than crustal events. Following the recent earthquakes in the Etna area (mainshock 26/12/2018 Mw = 4.9) and in the island of Ischia (mainshock 21/08/2017 Mw = 3.9), it was possible to increase the number of recordings for volcanic areas in Italy and, in particular, close to the epicentre. The data available after the recent events revealed the limitations of previous models and especially their inadequacy to predict the ground motion observed in the near source, that can be unexpectedly high. We calibrate a new empirical model to predict the amplitudes of several intensity measures for volcanic areas in Italy. The most relevant aspect in the proposed model is the different attenuation with the distance between shallow and deep events, with discerning focal depth fixed at 5 km. The equations are valid for the geometric mean of horizontal components of PGA, PGV and acceleration response spectra ordinates at 5% damping (in period range T = 0.025–5 s). The range of validity in magnitude is 3.5–4.9 and the hypocentral distance range is 1–200 km.

Changing Eruptive Styles at the South-East Crater of Mount Etna: Implications for Assessing Lava Flow Hazards

The summit area of Mount Etna has undergone large morphological variations since the formation of the South-East Crater (SEC) in 1971 and New Southeast Crater (NSEC) in 2007, which have also marked a notable change in the eruptive activity of the volcano. Indeed, in less than 50 years, the SEC area has been the source of more than two hundreds of eruptions characterized by the emission of lava fountains, pyroclastic material, and short-lasting lava flows, which are the greatest hazard presented to the tourist facilities on the southern flank of Etna. Here we statistically analyze the main quantitative parameters (i.e. duration and lava volume) of 154 well-documented eruptive events occurred since 1998 with the aim of characterizing the time-volume evolution of the SEC activity. From 1998 to 2018, we find a cumulative volume of ∼135 millions of cubic meters that gives a long-term output rate of ~0.21 m3/s, with a remarkable change in the eruptive style (longer and more voluminous events) starting from 2011. Taking advantage of this analysis and lava flow simulations run on a Pleiades-derived topography updated to 2016, we also present the new hazard map from lava flow inundation in the SEC area, establishing an important basis for mitigation decisions. Our SEC hazard map covers an area of ~15 km2, with lava flows spreading both towards south-west and south-east, reaching the lowest altitude of about 1,500 m a.s.l.

Time and space scattered volcanism of Mt. Etna driven by strike-slip tectonics

High-resolution seismic reflection, magnetic and gravity data, acquired offshore of Etna volcano, provide a new insight to understanding the relationship between tectonics and spatial-temporal evolution of volcanism. The Timpe Plateau, a structural high pertaining to the Hyblean foreland domain, located offshore of southeastern Mt. Etna, is speckled by volcanics and strongly affected by strike-slip tectonics. Transpressive deformation produced a push-up and a remarkable shortening along WNW-ESE to NW-SE trending lineaments. Fault segments, bounding basinal areas, show evidence of positive tectonic inversion, suggesting a former transtensive phase. Transtensive tectonics favoured the emplacement of deep magmatic intrusive bodies and Plio-Quaternary scattered volcanics through releasing zones. The continuing of wrench tectonics along different shear zones led to the migration of transtensive regions in the Etna area and the positive inversion of the former ones, where new magma ascent was hampered. This process caused the shifting of volcanism firstly along the main WNW-ESE trending “Southern Etna Shear Zone”, then towards the Valle del Bove and finally up to the present-day stratovolcano.

Petrographic and chemical characterization of Middle Bronze Age pottery from Sicily: towards a definition of an Etnean production

The Middle Bronze Age in Sicily (fifteenth–thirteenth century BC) represents a crucial moment in the evolution of Prehistoric pottery production. However, the scarcity of specific petrographic and chemical studies has represented until now a serious interpretative handicap for archeologists. The recent study of two important Middle Bronze Age pottery complexes from the Etnean area (Grotte di Marineo di Licodia Eubea and Monte San Paolillo di Catania) has offered the possibility to add new significant data to characterize the manufacturing practices behind such production. A new assemblage of Thapsos pottery from the Middle Bronze Age site of St. Ippolito hill at Caltagirone can shed new light on the features of such Etnean production. This paper highlights the potential of the application of an array of techniques such as petrographic analysis of thin sections and chemical analyses via X-ray fluorescence spectrometry and electron microprobe analysis to better investigate production technology of Middle Bronze Age Sicilian pottery.

Preliminary Indoor Radon Measurements Near Faults Crossing Urban Areas of Mt. Etna Volcano (Italy).

The slopes of Etna are crossed by numerous active faults that traverse various towns and villages. These faults pose a two-fold problem for the local people: on one hand, they cause frequent damage to houses and breakage of roads, while on the other they constitute a preferential route for the rising of crustal and sub-crustal gases, including radon, toward the surface. Various recent studies on the volcano confirm a high level of radon degassing measured both in the soil (> 10,000 Bq/m3), and inside homes (> 2,000 Bq/m3). For this reason, we felt the need to deepen our knowledge on the radon present in the Etnean area, focusing in particular on indoor radon pollution that, as widely recognized, is among the main causes of cancer largely (but not exclusively) of the respiratory system. Firstly, since 2005 we made a broad surface survey that revealed very high radon emissions from soils near active faults on Etna. Typical background soil activity on Etna were <1,000 Bq/m3, whereas in areas of stronger soil degassing, activity values up to ~60,000 Bq/m3 were measured. Furthermore, since late 2015 we have performed continuous indoor radon monitoring inside seven houses, some of which located close to degassing faults on the eastern, southern and south-western flanks of the volcano. Indoor radon concentration varied according to the season of the year, but above all, they changed according to the geology and tectonic setting of the substratum of the monitored houses. In one case, indoor radon concentration reached 3,549 Bq/m3 and remained > 1,000 Bq/m3 for several consecutive months, highlighting a potential health problem for those living in such environments. In other cases, the construction features of the houses and/or the materials used seemed to play an important role in the mitigation of indoor radon accumulation, even in the presence of intensely degassing soils. These preliminary data demonstrate the need to deepen the studies, extending indoor radon measurements to other urban areas, in order to monitor the health hazard for the Etna population, amounting to about one million people.

Volcanic risk and the role of the media. A case study in the Etna area

On December 24, 2018, the Etna volcano has recorded a significant eruption. Linked to this phenomenon, after a seismic swarm of 72 shocks, a 4.8-magnitude earthquake struck a large area North of Catania city, on the Eastern coast of Sicily. Six villages reported 28 injured people and damages to the building. According to seismologists the earthquake had an unusual level of magnitude. Yet, despite the real danger of this event, many people who live around the volcano, in one of the most densely populated areas of Sicily, perceived these facts in an ambivalent way. Indeed, their lives continued as before even in awareness of the natural hazard, while several media presented the situation as really dangerous in a worried tone. This paper, part of a wider research still in progress, aims to analyse the perception of the risk towards the biggest and highest volcano of Europe by the inhabitants of some villages that rise around the Etna. Based on a previous research conducted in 2013 in the same area, this study compares the ways in which this recent earthquake was perceived by some residents in the area and the ways in which some online newspaper narrated the event. Therefore, by analysing and comparing the first results that come from interviews realized during a fieldwork and from online newspaper/magazine articles, this study tries to understand, from a geographical and cultural perspective, how the perception of the risk can be narrated attributing different values to hazard. The latter can have pragmatic implications because from this symbolic evaluation may depend the behaviour of an entire community.

GIS and remote sensing for post-dictive analysis of archaeological features. A case study from the Etnean region (Sicily)

This article illustrates the potential of multispectral satellite data for archaeological scope in the volcanic area of Mount Etna (Sicily, Italy). In particular, by adopting a post-dictive approach, GIS and FOSS technology was used to analyse different indices derived from World-View-2 multispectral data. The selected examples (two circular buildings and a wall-structure) illustrate successes and challenges of our method. The results indicate that NIR-1 and RED-EDGE are undoubtedly the most useful, while NDVI and SRI are the best performing indices.

Elucidating the contribution of wild related species on autochthonous pear germplasm: A case study from Mount Etna.

The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in temperate climates. The Mount Etna area claims a large number of pear varieties differentiated due to a long history of cultivation and environmental variability, making this area particularly suitable for genetic studies. Ninety-five pear individuals were genotyped using the simple sequence repeat (SSR) methodology interrogating both the nuclear (nDNA) and chloroplast DNA (cpDNA) to combine an investigation of maternal inheritance of chloroplast SSRs (cpSSRs) with the high informativity of nuclear SSRs (nSSRs). The germplasm was selected ad hoc to include wild genotypes, local varieties, and national and international cultivated varieties. The objectives of this study were as follows: (i) estimate the level of differentiation within local varieties; (ii) elucidate the phylogenetic relationships between the cultivated genotypes and wild accessions; and (iii) estimate the potential genetic flow and the relationship among the germplasms in our analysis. Eight nSSRs detected a total of 136 alleles with an average minor allelic frequency and observed heterozygosity of 0.29 and 0.65, respectively, whereas cpSSRs allowed identification of eight haplotypes (S4 Table). These results shed light on the genetic relatedness between Italian varieties and wild genotypes. Among the wild species, compared with P. amygdaliformis, few P. pyraster genotypes exhibited higher genetic similarity to local pear varieties. Our analysis revealed the presence of genetic stratification with a ‘wild’ subpopulation characterizing the genetic makeup of wild species and the international cultivated varieties exhibiting the predominance of the ‘cultivated’ subpopulation.

HPLC and NMR analysis of the phenyl-ethanoid glycosides pattern of Verbascum thapsus L. cultivated in the Etnean area

In this work the HPLC and NMR analysis of the phenyl-ethanoid glycosides (PhGs) pattern of a cultivated exemplar of Verbascum thapsus L. (Scrophulariaceae) from the Etnean area (Sicily, Italy) was performed in order to verify their possible presence. Wild V. thapsus is well-known in ethnopharmacology due to the several beneficial effects that it is able to exert and which are primarily due to these compounds. So, it’s extremely important that also cultivated exemplars of this species biosynthesize them in order to maintain their pharmacological properties. This study revealed the presence of seven PhGs in an unusual novel pattern. Thus, this exemplar is a very good potential source of this class of natural products and may be employed for several beneficial ethnopharmacological purposes.