http://hdl.handle.net/2122/268 2013-05-20T07:46:45Z http://hdl.handle.net/2122/8583 Title: An innovative method for continuous measurement of soil CO2 flux Authors: De Gregorio, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Camarda, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Cappuzzo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Gurrieri, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia Abstract: Herein, we present a method for continuous measurement of soil CO2 flux that is completely new and distinct from existing instruments. The foremost difference is that instead of using an infrared gas analyser (IRGA), the new device measures soil CO2 flux by means of a simple pressure sensor, measuring pressure transients inside a closed polymeric tube inserted into the soil. This allows continuous measurements even in soil placed in environments that could potentially damage IRGA. In addition, due to the innovative operating principle, measurements of soil CO2 flux can be effortlessly performed also in strongly harsh weather conditions. Theoretical equations were derived for calculating soil CO2 flux solely using measured transient values. The reliability of the equations was rigorously tested with a variety of experiments. Continuous measurements over four months, acquired in a high-emission area on the Island of Vulcano, compared favourably with the data obtained using an established method. 2013-02-28T23:00:00Z http://hdl.handle.net/2122/8403 Title: Automatic real-time detection and location of Very Long Period events at Stromboli Authors: D'Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Cesare, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Scarpato, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: Signals with Very Long Periods (VLP) (1-60s) have been recorded on many active volcanoes. They are related with various dynamical processes in the volcano feeding system. Stromboli was one of the first volcanoes where such signals have been observed and analyzed. After the beginning of an anomalous eruptive activity in December 2002, a permanent broadband seismic network was deployed, by INGV-Osservatorio Vesuviano, in January 2003. Currently the network consists in 11 stations. Seismic data are continuously acquired by the INGV-Osservatorio Vesuviano in Naples, where they are analyzed in real time and stored. Preliminary results are immediately published on public web pages. In this paper we focus on the method used for detecting and locating VLP events. Such events have not a clear onset, so classical methods for automatic picking and location fails. Compared to common earthquakes signals, VLPs shows a high waveform coherence among different stations and a clear radial polarization toward the hypocenter. Using these features, hypocenters may be found searching for the points in the space having the highest coherence in the radial component. This is quantified using a modified semblance function over band-pass filtered (2-20 s) signals. The point having the highest semblance function value is the hypocenter. The semblance function is computed continuously for 10 s time windows over a regular grid centered on Stromboli, having a volume of 8000x8000x2000 m and a spacing of 100x100x50 m. VLP events are detected when the maximum value of the semblance function exceed a given threshold value. This task require heavy computation efforts. For this reason we use a 64 processor parallel computer for performing real-time analysis. 2004-03-31T22:00:00Z http://hdl.handle.net/2122/8402 Title: IL SISTEMA DI ANALISI AUTOMATICA DEI SEGNALI SISMICI VLP DELLO STROMBOLI Authors: D'Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Cesare, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Scarpato, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: Nel corso degli anni ‘90 l’uso di reti sismiche broadband in aree vulcaniche attive ha permesso di osservare in numerosi casi, segnali VLP (Very Long Period), ovvero segnali transienti con periodo dominante nella banda 2-50 s. Lo Stromboli, che con la sua persistente attività è un generatore di segnali VLP, è uno dei pochi vulcani su cui opera una rete sismica estesa costituita da stazioni broadband. A partire dal maggio 2003, è attivo presso la sede INGV Osservatorio Vesuviano un sistema automatico, denominato EOLO, per il rilevamento, la localizzazione e l’analisi in tempo reale di questi segnali. Il sistema EOLO riceve in ingresso (via internet) i segnali sismici registrati dalla rete broadband INGV dello Stromboli e fornisce, attraverso un’interfaccia web, sia i dati relativi ai singoli eventi VLP che delle statistiche giornaliere, mensili e annuali. L’interfaccia web interagisce con 3 database diversi: quello delle “forme d’onda”, il “catalogo eventi” e il database “statistiche”. Il database “forme d’onda” è costituito da un insieme di file in formato SAC, creati a partire dai segnali “grezzi” ricevuti in input. Il “catalogo eventi” rappresenta il cuore di tutto il sistema ed è implementato mediante SQL. Per ciascun evento VLP individuato, vengono determinati i parametri ipocentrali e le ampiezze alle varie stazioni e vengono inserite nel database “catalogo eventi”. Con periodicità oraria, viene aggiornato il database “statistiche”, costituito da grafici con gli andamenti orari e giornalieri del numero di eventi, della loro intensità e dell’andamento medio della polarizzazione dei segnali sismici VLP. L’interfaccia web consente di visualizzare, attraverso applet Java e script CGI, la localizzazione di ciascun evento, le forme d’onda, spettri e spettrogrammi, ed altre informazioni ritenute utili. Il sistema di rilevamento/localizzazione, che costruisce il database “catalogo eventi” è basato sull’analisi della coerenza delle forme d’onda VLP registrate alle varie stazione. Un calcolatore parallelo, basato su un cluster di 64 processori, esegue in tempo reale l’analisi della funzione semblance (indicativa della coerenza) su una griglia di dimensioni 8 km x 8 km x 2 km a spaziatura regolare 100 m x 100 m x 50 m, centrata sullo Stromboli. L’accadimento di un evento VLP produce il superamento di un valore di soglia della funzione semblance. La posizione del valore massimo della funzione semblance, durante un evento, è assunta come localizzazione. Nei prossimi mesi al sistema esistente sarà aggiunto un modulo per l’inversione della funzione sorgente dei singoli eventi VLP. 2003-08-31T22:00:00Z http://hdl.handle.net/2122/8396 Title: The Stromboli Volcano Broadband Seismic Monitoring System Authors: Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Cesare, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; D'Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Orazi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Scarpato, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Cattaneo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Badiali, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia Abstract: After the beginning of the eruptive crisis that has interested the Stromboli volcano (Southern Italy) at the end of 2002, starting the second half of January 2003 it has been installed on the island a centralized broadband seismic network, at present composed by 11 stations, all equipped with Guralp CMG-40T (0,02-60 s period). The network is one of the first designed to monitor and analyze in real time the very long periods (VLP) events, which are produced, in the case of the Stromboli volcano, at a rate of hundreds per day. The disposition of the stations has been chosen in order to realize an azimuth and distance homogeneously distribution regarding possible seismic sources situated along the upper part of feeding system of the volcano. The network shows a distribution of stations that encircle the volcanic structure to various levels regarding the area of craters and the eruptive vents, with distance of the stations from the emission centers that vary between some hundreds of meters to about 2 kilometers. The signals, acquired using 24 bits A/D data loggers designed by INGV - CNT, are transmitted via UHF radiomodems to two intermediate centralization sites . The first one is the Observatory of S. Vincenzo where are centralized the stations installed on the northern side of the island, the second is the Observatory INGV in the Lipari island, where are centralized all the other stations. From these two intermediate centralization sites the data are transmitted via TCP/IP protocol, using the Italian scientific-academic internet network GARR, towards the INGV monitoring centers of Catania and Observatory Vesuviano (Naples), where the broadband signals are monitored and processed, using a 64 CPU computer cluster to perform the VLP real-time analysis. 2004-03-31T22:00:00Z http://hdl.handle.net/2122/8308 Title: New insights into volcanic processes at Stromboli from Cerberus, a remote-controlled open-path FTIR scanner system Authors: La Spina, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Burton, M. R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Harig, R.; TUHH, Technical University of Hamburg-Harburg, Hamburg, Germany; Mure, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Rausch, P.; TUHH, Technical University of Hamburg-Harburg, Hamburg, Germany; Jordan, M.; TUHH, Technical University of Hamburg-Harburg, Hamburg, Germany; Caltabiano, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia Abstract: The ordinary, low intensity, activity of Stromboli volcano is sporadically interrupted by more energetic events termed, depending on their intensity, “major explosions” and “paroxysms”. These short-lived energetic episodes represent a potential risk to visitors to the highly accessible summit of Stromboli. Observations made at Stromboli over the last decade have shown that the composition of gas emitted from the summit craters may change prior to such explosions, allowing the possibility that such changes may be used to forecast these potentially dangerous events. In 2008 we installed a novel, remote-controlled, open-path FTIR scanning system called Cerberus at the summit of Stromboli, with the objective of measuring gas compositions from individual vents within the summit crater terrace of the volcano with high temporal resolution and for extended periods. In this work we report the first results from the Cerberus system, collected in August-September 2009, November 2009 and May-June 2010. We find significant, fairly consistent, intra-crater variability for CO2/SO2 and H2O/CO2 ratios, and relatively homogeneous SO2/HCl ratios. In general, the southwest crater is richest in CO2, and the northeast crater poorest, while the central crater is richest in H2O. It thus appears that during the measurement period the southwest crater had a somewhat more direct connection to a primary, deep degassing system; whilst the central and northeast craters reflect a slightly more secondary degassing nature, with a supplementary, shallow H2O source for the central crater, probably related to puffing activity. Such water-rich emissions from the central crater can account for the lower crystal content of its eruption products, and emphasise the role of continual magma supply to the shallowest levels of Stromboli's plumbing system. Our observations of heterogeneous crater gas emissions and high H2O/CO2 ratios do not agree with models of CO2-flushing, and we show that simple depressurisation during magma ascent to the surface is a more likely model for H2O loss at Stromboli. We highlight that alternative explanations other than CO2 flushing are required to explain distributions of H2O and CO2 amounts dissolved in melt inclusions. We detected fairly systematic increases in CO2/SO2 ratio some weeks prior to major explosions, and some evidence of a decrease in this ratio in the days immediately preceding the explosions, with periods of low, stable CO2/SO2 ratios between explosions otherwise. Our measurements, therefore, confirm the medium term (~ weeks) precursory increases previously observed with MultiGas instruments, and, in addition, reveal new, short-term precursory decreases in CO2/SO2 ratios. immediately prior to the major explosions. Such patterns, if shown to be systematic, may be of great utility for hazard management at Stromboli's summit. Our results suggest that intra-crater CO2/SO2 variability may produce short-term peaks and troughs in CO2/SO2 time series measured with in-situ MultiGas instruments, due simply to variations in wind direction. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8307 Title: How do volcanic rift zones relate to flank instability? Evidence from collapsing rifts at Etna Authors: Ruch, J.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy; Pepe, S.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy; Casu, F.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy; Acocella, V.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy; Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Solaro, G.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy; Sansosti, E.; National Research Council (CNR), Istituto per il Rilevamento Elettromagnetico dell'Ambiente (IREA), Napoli, Italy Abstract: Volcanic rift zones, characterized by repeated dike emplacements, are expected to delimit the upper portion of unstable flanks at basaltic edifices. We use nearly two decades of InSAR observations excluding wintertime acquisitions, to analyze the relationships between rift zones, dike emplacement and flank instability at Etna. The results highlight a general eastward shift of the volcano summit, including the northeast and south rifts. This steadystate eastward movement (1-2 cm/yr) is interrupted or even reversed during transient dike injections. Detailed analysis of the northeast rift shows that only during phases of dike injection, as in 2002, does the rift transiently becomes the upper border of the unstable flank. The flank's steady-state eastward movement is inferred to result from the interplay between magmatic activity, asymmetric topographic unbuttressing, and east-dipping detachment geometry at its base. This study documents the first evidence of steady-state volcano rift instability interrupted by transient dike injection at basaltic edifices. 2012-09-18T22:00:00Z http://hdl.handle.net/2122/8197 Title: Soil gases and SAR measurements reveal hidden faults on the sliding flank of Mt. Etna (Italy) Authors: Bonforte, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Federico, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Giammanco, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Guglielmino, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Liuzzo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia Abstract: From October 2008 to November 2009, soil CO2, radon and structural field surveys were performed on Mt. Etna, in order to acquire insights into active tectonic structures in a densely populated sector of the south-eastern flank of the volcano, which is involved in the flank dynamics, as highlighted by satellite data (InSAR). The studied area extends about 150 km2, in a sector of the volcano where InSAR results detected several lineaments that were not well-defined from previous geological surveys. In order to validate and better constrain these features with ground data evidences, soil CO2 and soil radon measurements were performed along transects roughly orthogonal to the newly detected faults, with measurement points spaced about 100 m. In each transect, the highest CO2 values were found very close to the lineaments evidenced by InSAR observations. Anomalous soil CO2 and radon values were also measured at old eruptive fractures. In some portions of the investigated area soil gas anomalies were rather broad over transects, probably suggesting a complex structural framework consisting of several parallel volcano-tectonic structures, instead of a single one. Soil gas measurements proved particularly useful in areas at higher altitude on Mt. Etna (i.e. above 900 m asl), where InSAR results are not very informative/ are fairly limited, and allowed recognizing the prolongation of some tectonic lineaments towards the summit of the volcano. At a lower altitude on the volcanic edifice, soil gas anomalies define the active structures indicated by InSAR results prominently, down to almost the coastline and through the northern periphery of the city of Catania. Coupling InSARwith soil gas prospectingmethods has thus proved to be a powerful tool in detecting hidden active structures that do not show significant field evidences. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8174 Title: Influence of volcanic gases on the epidermis of Pinus halepensis Mill. in Campi Flegrei, Southern Italy: A possible tool for detecting volcanism in present and past floras Authors: Bartiromo, A.; Dipartimento delle Scienze Biologiche, Università degli Studi di Napoli “Federico II” ; Université Lyon 1, F-69622, Lyon; CNRS, UMR5276, Laboratoire de Géologie de Lyon. Herbiers de l'Université Claude-Bernard Lyon 1, France Dipartimento di Scienze della Terra, Università degli Studi di Napoli “Federico II”,; Guignard, G.; Université Lyon 1, F-69622, Lyon; CNRS, UMR5276, Laboratoire de Géologie de Lyon. Herbiers de l'Université Claude-Bernard Lyon 1, France; Barone Lumaga, M. R.; Orto Botanico, Università degli Studi di Napoli “Federico II”, Via Foria, 223, 80139 Napoli, Italy; Barattolo, L.; Dipartimento di Scienze della Terra, Università degli Studi di Napoli “Federico II”, Largo San Marcellino, 10, 80138 Napoli, Italy; Chiodini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Avino, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Guerriero, G.; Dipartimento delle Scienze Biologiche, Università degli Studi di Napoli “Federico II”; Barale, G.; Université Lyon 1, F-69622, Lyon; CNRS, UMR5276, Laboratoire de Géologie de Lyon. Herbiers de l'Université Claude-Bernard Lyon 1, France Abstract: Cuticle micromorphology together with epidermal and epistomatal wax, in both current- and first-year-old needles of conifer Pinus halepensis (Aleppo pine) trees growing under volcanic gas fumigation was analysed in Pisciarelli area, Campi Flegrei, Southern Italy. As a control, current- and first-year-old needles growing far from volcanic gas emission were also sampled. Using a multidisciplinary approach with SEM, TEM and X-ray, volcanic gases were shown to cause degradation on epicuticular and epistomatal waxes. Significant statistical variations of ultrastructural components of the cuticle, with 30 measurements, including total thickness of the cuticle, and details and proportions of all different layers, and use of confidence interval, revealed a high degree of sensitivity of Aleppo pine to this extreme environment. In the present study, non-significant thickness variations of the cell wall plus cuticle among current- and first-year-old needles of both fumigated and non fumigated trees have been found. However, at the ultrastructural level, significant variations in cell wall and total cuticle thickness, especially within the three zones of B1 fibrillar layer, revealed different equilibria for each of the four types of material. Using energy dispersive X-ray microanalysis, no sulphur was found in either cuticle or epidermal cells, but the presence of H2S in the fumarole gas is suspected to cause indirect and/or direct cuticle alterations of wax structure. Ultrastructural characters of plant cuticles related to emission of volcanic gases during the geological past are also discussed. Among these considerations, an identification key enabling distinction between non fumigated and fumigated materials with 9 characters, provides a good tool detecting the influence of volcanism for extant and fossil plants. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8141 Title: Characterization of active fault scarps from LiDAR data: a case 1 study from Central 2 Apennines (Italy) Authors: Brunori, C. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Civico, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Cinti, F. R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: A high resolution DEM (1 ms spacing) derived from an airborne LiDAR campaign was 11 used in an attempt to characterize the structural and erosive elements of the geometry of the Pettino 12 fault, a seismogenic normal fault in Central Apennines (Italy). Four 90- to 280 m -long fault scarp 13 segments were selected and the surface between the base and the top of the scarps was analyzed 14 through the statistical analysis of the following DEM-derived parameters: altitude, height of the 15 fault scarp, distance along strike, slope and aspect. The results identify slopes of up to 40° in faults 16 lower reaches interpreted as fresh faces, 34° up the faces. The Pettino fault maximum long slipe17 rate (0.6-1.1 mm/yr) was estimated from the scarp heights, which are up to 12 and 19 m in the 18 selected four segments, and the age (ca. 18 ka) of the last glacial erosional phase in the area. The 19 combined analysis of the DEM-derived parameters allow us to (a) define aspects of 3D scarp 20 geometry, (b) decipher its geomorphological significance, and (c) estimate the long-term slip rate. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8128 Title: Heat and SO2 Emission Rates at Active Volcanoes - The Case Study of Masaya, Nicaragua Authors: Spampinato, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Salerno, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia Editors: Hwee-San, L.; Unversiti Sains Malaysia (USM) Abstract: No abstract included in the book chapter 2012-02-29T23:00:00Z