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Lo Castro, Maria Deborah
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Lo Castro, Maria Deborah
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- PublicationOpen AccessAnalisi tessiturale della cenere emessa dalla Bocca Nuova il 17 giugno 2011(2011)
; ; ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; 148 73 - PublicationOpen AccessTephrostratigraphy of the last 2 ka activity of Etna volcano(2010)
; ; ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Coltelli, Mauro; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Stratigraphic and facies analysis, conducted in the 90’s, on the pyroclastic successions blanking the Etna volcano flanks permitted the reconstruction of the last 100 ka tephrostratigraphic record of the volcano explosive activity. During the Holocene, several strong explosive events occurred, including a basaltic plinian eruption in 122 BC. However, the historical period lacks of detailed investigation on the Etna pyroclastic succession, therefore, we focused our research on this period. We started with an accurate field work aimed to the description of the pyroclastic deposits cropping out prevalently on the NE flank of the volcano. This tephra succession is characterized by alternations of ash layers, scoriaceous lapilli rich horizons and varicoloured tuffs attributed to a phreatomagmatic activity. Several yellowish volcanoclastic horizons, sometimes rich in charcoal, separate the tephra layers, indicating non-eruptive periods between the eruptions. We compiled 7 tephrostratigraphic sections having as common base the marker bed “FG” of the 122 BC plinian eruption and we collected 62 tephra samples and 7 charcoals for laboratories analysis. In particular, grainsize, component, chemical and petrographic analysis were carried out on tephra samples, whereas the charcoals were sent to Beta Analytics, Miami, for 14C radiometric analysis. The whole data set permitted us to correlate the tephra layers and to recognised 16 tephrostratigraphic units. The integration of the radiometric data with historical chronicles regarding the past activity of Etna, allow us to attribute some tephrostratigraphic units to 7 Etna historic eruptions whose distal deposit had never been found before. These eruptions could be considered as belonging to class B of Branca and Del Carlo (2005), characterised by prevalent intense explosive activity producing copious tephra fallouts, as happened during the 2001 and 2002-2003 eruptive events.214 395 - PublicationOpen AccessIl parossismo del 30 luglio 2011 al Cratere di SE: caratteristiche del deposito di caduta(2011)
; ; ; ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Scollo, Simona; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; 165 67 - PublicationOpen AccessContributo sull’attività esplosiva dell’8 aprile 2010 all’Etna(2010-04)
; ; ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; 304 65 - PublicationOpen AccessOperazioni di base per la misura della distribuzione granulometrica di particelle vulcaniche tramite il Camsizer(2008)
; ; ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; 123 2298 - PublicationOpen AccessOsservazioni sull’attività di Stromboli (16-19 giugno 2009)(2009)
; ; ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Tra il 16 e il 19 giugno 2009 è stata svolta una campagna sul vulcano Stromboli durante la quale è stata osservata l’attività eruttiva e raccolti alcuni campioni di cenere. In particolare sono state svolte delle ricognizioni in area sommitale nei giorni 16, 17 e 19 giugno 2009. La campagna ha avuto anche lo scopo di trasportare un campionatore di cenere sulla sommità del vulcano, che durante i giorni di osservazione è stato posizionato lungo l’asse di dispersione delle ceneri emesse dall’attività eruttiva. Quest’ultima è stata documentata da foto a colori reali e infrarosso; inoltre sono state eseguite alcune misure delle bocche presenti all’interno della terrazza craterica mediante un binocolo distanziometrico177 112 - PublicationRestrictedSEM-based methods for the analysis of basaltic ash from weak explosive activity at Etna in 2006 and the 2007 eruptive crisis at Stromboli(2012)
; ; ; ; ; ; ; ; ;Lautze, N. C.; University of Hawaii, Manoa, Department of Geology and Geophysics, United States ;Taddeucci, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cannata, C.; Univerista della Calabria, Italy ;Tornetta, L.; University of Hawaii, Manoa, Department of Geology and Geophysics, United States ;Scarlato, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Houghton, B.; University of Hawaii, Manoa, Department of Geology and Geophysics, United States ;Lo Castro, M. D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; ; ; We present results from a semi-automated field-emission scanning electron microscope investigation of basaltic ash from a variety of eruptive processes that occurred at Mount Etna volcano in 2006 and at Stromboli volcano in 2007. From a methodological perspective, the proposed techniques provide relatively fast (about 4 h per sample) information on the size distribution, morphology, and surface chemistry of several hundred ash particles. Particle morphology is characterized by compactness and elongation parameters, and surface chemistry data are shown using ternary plots of the relative abundance of several key elements. The obtained size distributions match well those obtained by an independent technique. The surface chemistry data efficiently characterize the chemical composition, type and abundance of crystals, and dominant alteration phases in the ash samples. From a volcanological perspective, the analyzed samples cover a wide spectrum of relatively minor ash-forming eruptive activity, including weak Hawaiian fountaining at Etna, and lava-sea water interaction, weak Strombolian explosions, vent clearing activity, and a paroxysm during the 2007 eruptive crisis at Stromboli. This study outlines subtle chemical and morphological differences in the ash deposited at different locations during the Etna event, and variable alteration patterns in the surface chemistry of the Stromboli samples specific to each eruptive activity. Overall, we show this method to be effective in quantifying the main features of volcanic ash particles from the relatively weak – and yet frequent – explosive activity occurring at basaltic volcanoes.169 25 - PublicationOpen AccessShape measurements of volcanic particles by CAMSIZER(2009-09)
; ; ; ; ; ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Nunnari, Giuseppe; Università degli Studi di Catania ;Spata, Alessandro; Università degli Studi di Catania ;Torrisi, Alessio; Università degli Studi di Catania; ; ; ; The shape of volcanic particles is an important parameter holding information related to physical and geochemical processes. The study of particle shape may help improving knowledge on the main eruptive processes (fragmentation, transport and sedimentation) during explosive activity. In general, volcanic ash is formed by different components, namely juvenile, lithic and crystal particles, each one characterized by peculiar morphology. Moreover, quantifying the shape of pyroclasts is needed by the most recent dispersal models that consider shape parameters as input data to simulate tephra dispersal. However, measuring and quantifying the particle shape of volcanic particles are hard challenges especially when the number of the particles to investigate is high and the size small (e.g. sub-millimetric). Several methods are currently used in volcanology, the most common probably being quantitative shape analysis by Scanning Electron Microscopy (SEM), based on the acquisition and subsequent analysis of digital images. Here, we describe a new methodology to measure the shape of volcanic particles by CAMSIZER®, a compact laboratory instrument developed by Retsch Technology (see http://www.retsch.com) for the simultaneous measurement of particle size distribution and particle shape of incoherent materials in the range of 30 µm to 30 mm, based on digital image processing. The sample is fed in from a vibrating feed channel that controls particles falling through the measurement field, where images of the particle are recorded by two digital cameras (Basic and Zoom) with different resolutions. Software, created by Retsch Technology, enables digital image processing to provide grain-size and shape parameters. This instrument, very common for quality control in industry, research and production monitoring of very different kinds of materials, has been installed at Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania (INGV-CT) to measure and validate grain-size distribution of volcanic particles (Lo Castro and Andronico, 2008; 2009). Recently, we made a new study to assess its use in analysing the shape of volcanic particles. Size and shape of particles are calculated by applying a number of mathematical models related to different geometric parameters that influence the final results. Measures of shape parameters (e.g. Feret diameter, roundness, symmetry, width, length) are performed under a high resolution scanning of each particle in 64 different directions. In order to study volcanic particle shape characteristics, we performed different tests on volcanic and non-volcanic materials, considering the most commonly used shape parameters. Finally, we compared and validated the obtained results with those carried out by binocular microscope image analysis on the same samples. Furthermore, on the basis of these measurements, a clustering analysis is proposed. In particular, the Self Organized Map (SOM) and the K-means algorithm have been used jointly in order to partition a generic sample of volcanic ash particles into subsets sharing some common shape features. A fuzzy c-mean analysis has also been used to verify and compare results. These analyses were aimed at developing an automatic shape clustering of the volcanic ash particles. Preliminary results of both image analysis and statistical testing are shown to understand if CAMSIZER is a suitable tool for quantifying and characterizing volcanic particle shapes.384 296 - PublicationOpen AccessContributo sull’attività di emissione di cenere del 25 agosto 2010 all’Etna(2010-08)
; Lo Castro, Maria Deborah114 60 - PublicationOpen AccessIl parossismo del 12-13 gennaio 2011 al Cratere di SE: caratteristiche del deposito di caduta.(2011)
; ; ; ; ; ; ; ;Andronico, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, Antonio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, Maria Deborah; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Scollo, Simona; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Ciancitto, Francesco; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Distefano, Salvatore; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lodato, Luigi; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; ; 262 300
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