http://hdl.handle.net/2122/54 Ricerca nel canale cerca http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/6082 Titolo: Integrated SEED data archive for temporary seismic experiments<br/><br/>Autori: Moretti, Milena; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Govoni, Aladino; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Margheriti, Lucia; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Mandiello, Alfonso Giovanni; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Pintore, Stefano; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Di Stefano, Raffaele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Chiaraluce, Lauro; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Baccheschi, Paola; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Lauciani, Valentino; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Marcocci, Carlo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Mazza, Salvatore; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia<br/><br/>Abstract: One of the most valuable results achieved duringthe work on S5 project is the implementation of a new temporarynetwork data management that allows the integration in theNational Data Center together with all other seismological data producedby INGV. This makes all data gathered during temporary experiments immediatelyavailable from the same source and in the same data format (SEED)increasing the availability for processing and analysis. Moreover the data are distributedto the scientific community using the EIDA (European Integrated Data Archivehttp://eida.rm.ingv.it/).The first application has been carried out for the Messina 1908-2008 experiment(WP2.2) http://dpc-s5.rm.ingv.it/en/Database-MessinaFault.html where has beenachieved the complete integration of permanent networks (National Seismic Network,MedNet and Peloritani Local Network), temporary deployments (INGV-CNT and INGVCTmobile networks) and OBS data.All the procedures were used and further improved during the L'Aquila sequence(Task 4) where data was available for processing together with permanentnetwork data as soon as it was gathered from the field giving to thescientific community the opportunity to study the evolution of theseismic sequence with higher density of stations (WP4.2)( h t t p : / / d p c - s 5 . r m . i n g v . i t / e n / D a t a b a s e -AquilaFaultSystem.html). http://hdl.handle.net/2122/6075 Titolo: High-Frequency Maximum Observable Shaking Map of Italy from Fault Sources<br/><br/>Autori: Zonno, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Basili, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Meroni, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Musacchio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Mai, P. M.; King Abdullah University of Science and Technology (Thuwal, Saudi Arabia); Valensise, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: This study presents the innovative concept of maximum observable shaking (MOS) maps. Our approach makes use of the improved understanding of the Italian regional tectonic setting and uses composite seismic sources (CSS) taken from an Italian database of individual seismic sources. The CSS are merged with high-frequency scenario calculations of expected maximum shaking in a given area. The results of the MOS evaluation in terms of peak ground acceleration and peak ground velocity have been converted into Mercalli-Cancani-Sieberg intensities and are compared with historical felt intensities from the Italian DBMI04 macroseismic database. http://hdl.handle.net/2122/6063 Titolo: Design earthquakes’ map: an additional tool for engineering seismic risk analysis. Application to southern Apennines (Italy).<br/><br/>Autori: Convertito, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Iervolino, I.; Dipartimento di Ingegneria Strutturale, Università di Napoli Federico II. Napoli; Herrero, A.; Istituto Nazionale di Geofisica e Vulcanologia. Roma<br/><br/>Abstract: Probabilistic seismic hazard analysis (PSHA) is currently the soundest basis for the evaluation of the hazard forsite-specific engineering design purposes. An increasing number of building codes worldwide acknowledges theuniform hazard spectra as the reference ground motion to determine design actions on structures and to select inputsignals for seismic structural analysis. The new Italian seismic code requires the seismic input for nonlineardynamic analysis to be selected on the basis of dominating events, e.g., identified via disaggregation of seismichazard. In the present study, the design earthquakes expressed in terms of magnitude (M), distance (R) and ε, wereinvestigated for a wide region in the southern Apennines, Italy. The hazards corresponding to peak groundacceleration and spectral acceleration at 1 second having 475-year return period were disaggregated. For each ofthe disaggregation variables the shapes of the joint and marginal probability density functions were studied and thefirst two modes of M, R and ε were extracted and mapped. The obtained results can be used as additionalinformation to better identify the design earthquakes. Moreover, for the study area, they allow the assessment of theseismic source contribution to various frequency ranges of the design spectrum. http://hdl.handle.net/2122/6052 Titolo: Support Vector Machines and MLP for automatic classification of seismic signals at Stromboli volcano<br/><br/>Autori: GIACCO, F.; Department of Physics, University of Salerno, Italy; ESPOSITO, A.M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; SCARPETTA, S.; Department of Physics, University of Salerno, Italy; INFN and INFM CNISM, Salerno, Italy; Institute for Advanced Scientific Studies, Vietri sul Mare, Italy, Germany; GIUDICEPIETRO, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; MARINARO, M.; Department of Physics, University of Salerno, Italy; INFN and INFM CNISM, Salerno, Italy; Institute for Advanced Scientific Studies, Vietri sul Mare, Italy, Germany<br/><br/>Curatori: Apolloni, B.; Università degli Studi di Milano, Dipartimento di Scienze dell’Informazione,Milano, Italy; Bassis, S.; Università degli Studi di Milano, Dipartimento di Scienze dell’Informazione,Milano, Italy; Morabito, C.F.; Università di Reggio Calabria, IMET, Loc. Feo di Vito,Reggio Calabria, Italy<br/><br/>Abstract: We applied and compared two supervised pattern recognition techniques,namely the Multilayer Perceptron (MLP) and Support Vector Machine (SVM),to classify seismic signals recorded on Stromboli volcano. The available data arefirstly preprocessed in order to obtain a compact representation of the raw seismicsignals. We extract from data spectral and temporal information so that each inputvector is made up of 71 components, containing both spectral and temporal informationextracted from the early signal. We implemented two classification strategiesto discriminate three different seismic events: landslide, explosion-quake, andvolcanic microtremor signals. The first method is a two-layer MLP network, witha Cross-Entropy error function and logistic activation function for the output units.The second method is a Support Vector Machine, whose multi-class setting is accomplishedthrough a 1vsAll architecture with gaussian kernel. The experimentsshow that although the MLP produces very good results, the SVM accuracy is alwayshigher, both in term of best performance, 99.5%, and average performance,98.8%, obtained with different sampling permutations of training and test sets http://hdl.handle.net/2122/6030 Titolo: GEOCHEMICAL CHARACTERIZATION OF NATURAL GAS MANIFESTATIONS IN GREECE<br/><br/>Autori: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Martelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Rizzo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Kyriakopoulos, K.; University of Athens, Dept. Geology and Geoenvironment, Greecey<br/><br/>Curatori: Koukis, G.; University of Patras; Zelilidis, A.; University of Patras; Koukouvelas, I.; University of Patras; Papatheodorou, G.; University of Patras; Geraga, M.; University of Patras; Zygouri, V.; University of Patras<br/><br/>Abstract: The Greek region is characterized by intense geodynamic activity with widespread volcanic,geothermal and seismic activity. Its complex geology is reflected in the large variety of chemicaland isotopic composition of its gas manifestations.Basing on their chemical composition the gases can be subdivided in three groups, respectivelyCO2, CH4 or N2-dominated. On oxygen-free basis these three gases make up more than 97% of thetotal composition. The only exceptions are fumarolic gases of Nisyros that contain substantialamounts of H2S (up to more than 20%) and one sample of Milos that contains 15% of H2. CO2-dominated gases with clear mantle contribution in their He isotopic composition (R/Ra correctedfor air contamination ranging from 0.5 to 5.7) are found along the subduction-related southAegean active volcanic arc and on the Greek mainland close to recent (upper Miocene toPleistocene) volcanic centers. These areas are generally characterized by active or recentextensive tectonic activity and high geothermal gradients. On the contrary, gases sampled in themore external nappes of the Hellenide orogen have generally a CH4- or N2-rich compositions andhelium isotope composition with a dominant crustal contribution (R/Ra corr < 0.2).The chemical and isotopic characteristics of the emitted gas display therefore a clear relationshipwith the different geodynamic sectors of the region. Gas geochemistry of the area contributes to abetter definition of the crust-mantle setting of the Hellenic region. http://hdl.handle.net/2122/6029 Titolo: Static chamber methane flux measurements in volcanic/geothermal areas: preliminary data from Sousaki and Nisyros (Greece)<br/><br/>Autori: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Fiebig, J.; University of Frankfurt a.M., Inst. für Geowissenschaften, Germany; Kyriakopoulos, K.; University of Athens, Dept. Geology and Geoenvironment, Greece; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Maneta, V.; University of Athens, Dept. Geology and Geoenvironment, Greecey; Michas, G.; University of Athens, Dept. Geology and Geoenvironment, Greece; Papadakis, G.; University of Athens, Dept. Geology and Geoenvironment, Greece<br/><br/>Abstract: Methane plays an important role in the Earth’s atmospheric chemistry and radiative balance being the secondmost important greenhouse gas after carbon dioxide. Methane is released to the atmosphere by a wide numberof sources, both natural and anthropogenic, with the latter being twice as large as the former (IPCC, 2007). Ithas recently been established that significant amounts of geological methane, produced within the Earth’s crust,are currently released naturally into the atmosphere (Etiope, 2004). Active or recent volcanic/geothermal areasrepresent one of these sources of geological methane. But due to the fact that methane flux measurements arelaboratory intensive, very few data have been collected until now and the contribution of this source has been generallyindirectly estimated (Etiope et al., 2007). The Greek territory is geodynamically very active and has manyvolcanic and geothermal areas. Here we report on methane flux measurements made at two volcanic/geothermalsystems along the South Aegean volcanic arc: Sousaki and Nisyros.The former is an extinct volcanic area of Plio-Pleistocene age hosting nowadays a low enthalpy geothermal field.The latter is a currently quiescent active volcanic system with strong fumarolic activity due to the presence of ahigh enthalpy geothermal system.Both systems have gas manifestations that emit significant amounts of hydrothermal methane and displayimportant diffuse carbon dioxide emissions from the soils. New data on methane isotopic composition and higherhydrocarbon contents point to an abiogenic origin of the hydrothermal methane in the studied systems.Measured methane flux values range from –48 to 29,000 (38 sites) and from –20 to 1100 mg/mˆ2/d (35 sites) atSousaki and Nisyros respectively.At Sousaki measurement sites covered almost all the degassing area and the diffuse methane output can beestimated in about 20 t/a from a surface of about 10,000 mˆ2.At Nisyros measurements covered the Stephanos and Kaminakia areas, which represent only a part of the entiredegassing area. The two areas show very different methane degassing pattern with latter showing much higherflux values. Methane output can be estimated in about 0.25 t/a from an area of about 30,000 mˆ2 at Stephanos andabout 1 t/a from an area of about 20,000 mˆ2 at Kaminakia. The total output from the entire geothermal system ofNisyros probably should not exceed 2 t/a. http://hdl.handle.net/2122/6028 Titolo: Environmental impact of Mt. Etna’s degassing: volcanogenic trace elements bioaccumulation in two endemic plant species (Senecio aethnensis and Rumex aethnensis)<br/><br/>Autori: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Calabrese, S.; Università di Palermo, Dipartimento CFTA; Bellomo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Di Maio, G.; Università di Palermo, Dipartimento CFTA; Parello, F.; Università di Palermo, Dipartimento CFTA; Saiano, F.; Università di Palermo, Dipartimento ITAF<br/><br/>Abstract: A biomonitoring survey, above tree line level, using two endemic species (Senecio aethnensis and Rumex aethnensis)was performed on Mt. Etna, in order to evaluate the dispersion and the impact of volcanic atmosphericemissions. Samples of leaves were collected in summer 2008 from 30 sites in the upper part of the volcano (1500-3000 m a.s.l). Acid digestion of samples was carried out with a microwave oven, and 44 elements were analyzedby using plasma spectrometry (ICP-MS and ICP-OES). The highest concentrations of all investigated elementswere found in the samples collected closest to the degassing craters, and in the downwind sector, confirming thatthe eastern flank of Mt. Etna is the most impacted by volcanic emissions. Leaves collected along two radial transectsfrom the active vents on the eastern flank, highlight that the levels of metals decrease one or two orders ofmagnitude with increasing distance from the source. This variability is higher for volatile elements (As, Bi, Cd,Cs, Pb, Sb, Tl) than for more refractory elements (Al, Ba, Sc, Si, Sr, Th, U). The two different species of plants donot show significant differences in the bioaccumulation of most of the analyzed elements, except for lanthanides,which are systematically enriched in Rumex leaves. The high concentrations of many toxic elements in the leavesallow us to consider these plants as highly tolerant species to the volcanic emissions, and suitable for biomonitoringresearches in the Mt. Etna area. http://hdl.handle.net/2122/6027 Titolo: Estimation of the magmatic gas and heat flux through the Etnean volcanic aquifer<br/><br/>Autori: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia<br/><br/>Abstract: Etna volcano, Italy, hosts one of the major groundwater systems of the island of Sicily. Waters circulate withinhighly permeable fractured, mainly hawaiitic, volcanic rocks. Aquifers are limited downwards by the underlyingimpermeable sedimentary terrains. Thickness of the volcanic rocks generally does not exceed some 300 m,preventing the waters to reach great depths. This is faced by short travel times (years to tens of years) and lowthermalisation of the Etnean groundwaters. Measured temperatures are, in fact, generally lower than 25 °C. Butthe huge annual meteoric recharge (about 0.97 kmˆ3) with a high actual infiltration coefficient (0.75) implies agreat underground circulation. During their travel from the summit area to the periphery of the volcano, watersacquire magmatic heat together with volcanic gases and solutes through water-rock interaction processes.In the last 20 years the Etnean aquifers has been extensively studied. Their waters were analysed for dissolvedmajor, minor and trace element, O, H, C, S, B, Sr and He isotopes, and dissolved gas composition. These data havebeen published in several articles. Here, after a summary of the obtained results, the estimation of the magmaticheat flux through the aquifer will be discussed.To calculate heat uptake during subsurface circulation, for each sampling point (spring, well or drainage gallery)the following data have been considered: flow rate, water temperature, and oxygen isotopic composition. Thelatter was used to calculate the mean recharge altitude through the measured local isotopic lapse rate. Meanrecharge temperatures, weighted for rain amount throughout the year, were obtained from the local weather stationnetwork. Calculations were made for a representative number of sampling points (216) including all major issuesand corresponding to a total water flow of about 0.315 kmˆ3/a, which is 40% of the effective meteoric recharge.Results gave a total energy output of about 140 MW/a the half of which is ascribable to only 13 sampling points.These correspond to the highest flow drainage galleries with fluxes ranging from 50 to 1000 l/s and wells withpumping rates from 70 to 250 l/s. Geographical distribution indicates that, like magmatic gas leakage, heat flowis influenced by structural features of the volcanic edifice. The major heat discharge through groundwater are alltightly connected either to the major regional tectonic systems or to the major volcanic rift zones along whichthe most important flank eruptions take place. But rift zones are much more important for heat upraise due to thefrequent dikes injection than for gas escape because generally when dikes have been emplaced the structure is nomore permeable to gases because it becomes sealed by the cooling magma. http://hdl.handle.net/2122/6023 Titolo: Integrated methodologies for 3D deformation analysis at Ischia Island (Italy): state of the art, prospectives and modelling.<br/><br/>Autori: Sepe, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Vilardo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia<br/><br/>Abstract: Ischia Island, located SW of Naples (Italy), has been characterized by both explosive and effusive activity with the last eruption occurred in 1302. Subsequent dynamics, characterized by seismic activity with the strongest events occurred in 1881 and 1883 and a diffuse hydrothermal phenomena, shows a significant subsidence in the S and NW sectors. The presence of the active volcanoes in a very densely area needs continuous monitoring of the dynamics related to the pre-eruptive processes. Ground deformation studies are an important precursor because are linked to magma overpressure and migration. In particular, the geodetic monitoring system is mainly based on GPS and Precise levelling techniques. Here, we present a study of the surface deformation occurring in the island based on Differential Synthetic Aperture Radar Interferometry (DInSAR) referred to as Small BAseline Subset (SBAS) technique. Levelling surveys carried out between 1990 and 2003 on the Mt Epomeo resurgent block record negative dislocations on the northern and southern flanks with a maximum subsidence rate of 1.27 cm/yr. This deformation is not associated with cooling, crystallization or lateral drainage of magma and cannot be explained by a pressure point or prorate ellipsoid source. The data show that between 1990 and 2003 Mt Epomeo has been affected by a subsidence with two maxima located on its northern and southern sectors. Then, the 1992–2003 time interval and SAR data acquired by the European Remote Sensing (ERS) satellites from ascending and descending orbits have been used, thus allowing us to discriminate the vertical and east–west components of the displacements. A validation of the DInSAR results has been carried out first by comparing the vertical deformations estimated from the SAR data with those measured from the spirit levelling network that is present in the area. The deformation is due to the closure of cracks associated with ENE–WSW to E–W preexisting faults along which degassing processes occur. We propose that the recorded dislocations reflect a decrease in the fluid pressure within these cracks. http://hdl.handle.net/2122/6022 Titolo: Monitoring and structural significance of ground deformations at Campi Flegrei supervolcano (Italy) from the combined 2D and 3D analysis of PS-InSAR, geophysical, geological and structural data<br/><br/>Autori: Ventura, Guido; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Vilardo, Giuseppe; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Sepe, Vincenzo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia<br/><br/>Abstract: Cities are growing around active volcanoes. Campi Flegrei supervolcano (CF, Italy) is a nested structure formed during two main collapses associated with two caldera-forming eruptions at 39 ka and 15 ka. The last event occurred in AD1538 (Monte Nuovo volcano). CF hosts 350,000 people and two main uplift phases were recorded in 1968–1972 and1982–1984 with deformations of about 2 m. The town of Pozzuoli was partially evacuated during the last crisis.Subsequent minor deformations (subsidence and uplift), seismicity, and diffuse CO2 degassing concentrate in the centralpart of the caldera. Here, we apply the Permanent Scatterers Synthetic Aperture Radar Interferometry (PS-InSAR) toinvestigate the ground deformations of CF by using data acquired from 1993 to 2007 from ascending and descendingtracks by ERS-1 ,ERS-2 and RADARSAT satellites. Deformation maps identify a subsidence interrupted by micro-upliftepisodes. These maps are combined with digitized topographic, geological (faults and landslides), seismic, andurbanization data. The merged information allow us to identify the areas involved in the deformation and the volcanotectonicstructures activated during the uplift and subsidence episodes. We propose a structural-volcanological model for the unrest pisodes. Data indicate that uplift episodes, which re associated to seismicity, are followed by subsidenceepisodes accommodated by pre-existing faults. The urbanized areas subjected to the higher deformations and shaking arealso identified and mapped. A multi-hazard zonation including landslides is also provided. The approach used here maybe utilized to (a) recognize the tectonic and/or volcanic structures activated during ground deformations, (b) toinvestigate structural models, (c) to evaluate and map multi-risk zonations, and (c) monitor other volcanic areas or nonvolcanic zones subjected to gravity instability or tectonics.