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Sicali, Antonino
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Sicali, Antonino
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antonino.sicali@ingv.it
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23 results
Now showing 1 - 10 of 23
- PublicationOpen AccessStrumento di Diagnostica e Amministrazione Remota di reti per il monitoraggio di parametri geofisici(2017)
; ; ; ; ; La manutenzione dei sistemi di monitoraggio remoto è importante poiché permette a un sistema di continuare a funzionare in modo continuo e duraturo. La stabilità dei sistemi dipende dal tipo di manutenzione che si esegue [Sicali et al., 2016]. La manutenzione copre diversi aspetti, dalla cura delle infrastrutture fino alla consistenza del software, passando per il benessere dell’hardware (elettronica). La cura delle infrastrutture deve essere effettuata in sito, per lo più realizzata come manutenzione ordinaria programmabile. Riguarda tutto ciò che risente delle intemperie e che è sottoposta a stress meccanici, di temperatura, ossidazione e corrosione. La manutenzione del software e dell’hardware, normalmente, viene effettuata di fronte a un problema già conclamato, che non si è potuto prevedere e/o programmare. Lo scopo del sistema esaminato di seguito è quello di aiutare, in una qualche misura, a prevedere i malfunzionamenti prima che si verifichino attraverso il constante monitoraggio di particolari segnali. Ciò che negli hard disk è stato realizzato attraverso l’adozione dei sistemi S.M.A.R.T [Wikipedia, Self-Monitoring, Analysis and Reporting Technology].155 14 - PublicationOpen AccessMagma Migration at Shallower Levels and Lava Fountains Sequence as Revealed by Borehole Dilatometers on Etna Volcano(2021-09-08)
; ; ; ; ; ; ; A main challenge in open conduit volcanoes is to detect and interpret the ultra-small strain (<10–6) associated with minor but critical eruptions such as the lava fountains. Two years after the flank eruption of December 2018, Etna generated a violent and spectacular eruptive sequence of lava fountains. There were 23 episodes from December 13, 2020 to March 31, 2021, 17 of which in the brief period 16 February to 31 March with an intensified occurrence rate. The high-precision borehole dilatometer network recorded significant strain changes in the forerunning phase of December 2020 accompanying the final magma migration at the shallower levels, and also during the single lava fountains and during the entire sequence. The source modeling provided further information on the shallow plumbing system. Moreover, the strain signals also gave useful information both on the explosive efficiency of the lava fountains sequence and the estimate of erupted volume. The high precision borehole dilatometers confirm to be strategic and very useful tool, also to detect and interpret ultra-small strain changes associated with explosive eruptions, such as lava fountains, in open conduit volcanoes.508 16 - PublicationOpen AccessMagnetic signatures of subsurface faults on the northern upper flank of Mt Etna (Italy)(2021)
; ; ; ; ; A ground magnetic study was performed on the northern upper flank of Mt. Etna to provide new insights into subsurface volcano-tectonic structures. The high resolution magnetic survey was focused on the main structures of Piano delle Concazze, a large flat area dominated by the North- East crater and bounded by the rim of the Valle del Leone depression and the extremity of the North-East Rift. More than 2,500 measurements were gathered with a sampling step of about 3 m covering an area of about 0.2 km2. The total-intensity anomaly field shows the presence of intense South-North aligned maxima related to shallow geological structures affecting this area. Filtering techniques and 2.5D modeling have been applied for the determination of the magnetic source parameters. In order to distinguish the near surface structure, filters of the vertical derivatives, Butterworth high-pass and the tilt derivative were used. The 3D Euler deconvolution has been applied to estimate the depth and the structural indices of the causative sources. The calculated structural indices, that express the geometrical nature of the source, are in agreement with forward modeling. They show that the area is mainly affected by subvertical normal fault and the estimated depth of magnetic sources ranges between 10 m and 40 m. Our total field magnetic survey shows that characteristic magnetic anomalies are related to fault zones in the Piano delle Concazze that are well consistent with the local tectonics. The subsurface structures that have been detected allowed to delineate the general structural framework of the area. In particular, it was possible to clarify that these structures seem to be not deep rooted and consequently they can hardly act as preferential pathways for magma ascent.475 60 - PublicationRestrictedGEOFIM: a WebGIS application for integrated geophysical modelling in active volcanic regions(2014)
; ; ; ; ; ; ; ; ; We present GEOFIM (GEOphysical Forward/Inverse Modeling), a WebGIS application for integrated interpretation of multiparametric geophysical observations. It has been developed to jointly interpret scalar and vector magnetic data, gravity data, as well as geodetic data, from GPS, tiltmeter, strainmeter and InSAR observations, recorded in active volcanic areas. GEOFIM gathers a library of analytical solutions, which provides an estimate of the geophysical signals due to perturbations in the thermal and stress state of the volcano. The integrated geophysical modeling can be performed by a simple trial and errors forward modeling or by an inversion procedure based on NSGA-II algorithm. The software capability was tested on the multiparametric data set recorded during the 2008-2009 Etna flank eruption onset. The results encourage to exploit this approach to develop a near-real-time warning system for a quantitative model-based assessment of geophysical observations in areas where different parameters are routinely monitored.419 3 - PublicationOpen AccessLinee guida e criticità nella progettazione di sistemi per l’acquisizione di dati geofisici in prossimità di vulcani attivi(2016)
; ; ; ; ; Nel monitoraggio e nella sorveglianza dei vulcani attivi ricoprono un ruolo di prim’ordine i sistemi di acquisizione dati. In commercio esistono già diversi sistemi pronti all’uso, utilizzabili per acquisire i più svariati tipi di segnali, quindi l’idea di progettare un nuovo sistema può sembrare alquanto strana. Ciononostante, molto spesso, non si riesce a trovare ciò di cui si ha bisogno e questo porta alla necessità di compiere qualche adattamento, ottenendo il più delle volte un sistema ibrido, instabile e troppo complesso. L’esperienza maturata negli anni ha permesso d’identificare poche decine di punti essenziali per il buon funzionamento dei sistemi di acquisizione. Questo documento nasce dalla necessità di riunire tali specifiche e ottenere un promemoria da seguire, sia in fase di progettazione che durante l’esame di un sistema esistente. Si può quindi utilizzare il documento anche per classificare qualunque sistema di acquisizione, in termini di affidabilità ed efficienza, che debba essere utilizzato in aree di estremo funzionamento. Le zone di estremo funzionamento sono tutte quelle in cui i parametri come la temperatura e l’umidità raggiungono valori limite, in cui possono essere presenti gas corrosivi, condizioni meteo estreme come alluvioni, neve, forte vento, tempeste di sabbia, e nel caso specifico dei vulcani, colate e fontane di lava. Le specifiche riportate in seguito derivano essenzialmente dall’esperienza maturata negli ultimi due decenni grazie all’osservazione quanto più oggettiva possibile del comportamento e dei problemi riscontrati nei sistemi dislocati sul M.te Etna e sull’Isola di Stromboli. Le specifiche sono riassunte sinteticamente nelle tabelle 1 e 2 allegate. Il testo non si prefigge lo scopo di esaurire completamente gli argomenti trattati ma di creare uno spunto di discussione sui sistemi di acquisizione. Dovrebbe permettere, soprattutto a chi non ha precedente esperienza sull’argomento, di evitare alcuni errori grossolani nella progettazione e di assicurarsi la buona riuscita di un progetto. Non sono importanti i dettagli poiché cambiano per ciascuna applicazione ma sono invece importanti le linee guida e la filosofia con cui si affronta il problema.172 19 - PublicationOpen AccessNear real-time filtering of high precision borehole strainmeter signalsfor volcano surveillance(2022)
; ; ; ; ; ; ; Volumetric strain signal recorded by the Sacks-Evertson strainmeter has a very high resolution and can measure small strain changes (down to 10(-9)) accompanying volcanic processes. However, different disturbing components perturb the recorded strain signal. These disturbances can mask ultra-small strain changes related to volcano activity and thus need to be filtered in order to accurately monitor volcano deformation. We developed the software STRALERT (STRain and wArning signaLs in nEar Real-Time) to provide both the recorded and the filtered strain signals in near real-time to the Surveillance Room of the "Istituto Nazionale di Geofisica e Vulcanologia - Osservatorio Etneo" which monitors the Etna activity. The software encloses a modified version of the code BAYTAP-G for filtering the incoming signal from the continuously running strainmeter at Etna. Thanks to the appropriate and robust signal filtering, STRALERT is capable to provide anefficient estimate of transient strain changes, which concur in tracing volcano deformation and detecting the onset and the conclusion of eruptive events. Our findings demonstrate the important contribution of STRALERT for volcano surveillance operations.330 35 - PublicationRestrictedA multidisciplinary strategy for in-situ and remote sensing monitoring of areas affected by pressurized fluids: Application to mud volcanoes: A multidisciplinary environmental monitoring strategy(2016)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Abstract — A multidisciplinary strategy integrating a data set obtained using different mthods and techniques, ranging from remote sensing (UAV system, FTIR, thermal imaging) to direct field measurements (soil heat flux, soil CO2 flux, gravimetry and geomagnetism) proved highly capable of modeling regions affected by pressurized fluids circulation and extreme natural environments. As a test site, the Salinelle mud volcanoes area, located close to the city of Paternò (Sicily), was selected. This area is characterized by gas exhalations through water/mud vents. Detailed morpho-structural information, GIS thematic maps and geochemail signature of the released gas were quickly retrieved. This study showed that by integrating and harmonizing many disciplines of geosciences it is possible to get a comprehensive geological model of the studied area. Results, showed the accurate detection of structural setting of such an area and the opportunuty to monitor the spatial/temporal evolution of water/mud vents. The proposed approach allowed to expand the use of each single technique beyond its traditional applications and to make it a potential tool for many fields of geoscience.1760 6 - PublicationOpen AccessReal-time signal processing of high-precision borehole strainmeters atMt. Etna for volcanic surveillance and eruptive events detection(2022-06-23)
; ; ; ; ; ; ; Borehole strainmeter observations at Etna volcano have revealed strain variations associated with volcano activity. In order to automatically identify volcano-related strain changes and track the eruptive activity, we designed the program STRALERT to provide an efficiently filtered strain signal and perform the event detection. By running in near real time, STRALERT contributes to volcanic surveillance operations.377 23 - PublicationOpen AccessAdvances in Understanding Intrusive, Explosive and Effusive Processes as Revealed by the Borehole Dilatometer Network on Mt. Etna Volcano(2020)
; ; ; ; ; ; ; ; ; For detecting below surface sources of deformation, strain measurements offer a very large advantage (orders of magnitude) in sensitivity over displacement measurements. On active volcanoes an intriguing open challenge is to measure the strain variations caused by the different types of eruptive activity with the highest possible precision in order to obtain advantages on the clear detecting of phenomena, their modeling and understanding. We present the updated main results obtained from the high precision strain recorded by the borehole dilatometer network on Mt. Etna volcano. The instruments, installed from the end of 2011, detected significant changes during different types of eruptive activity: several lava fountains during 2011–2014; two explosive sequences in 2015 and 2016; moderate effusive activity in 2017 and a dike intrusion in 2018. The strain changes provided powerful diagnostic information on the different ongoing processes, and allowed us to add key information on the different eruptive styles and sources. We also highlight how the recorded signals, with the associated modeling and interpretation, provide a powerful contribution to surveillance requirements on an active volcano. This report demonstrates that the borehole dilatometer network represents a useful tool both for the understanding of the volcano processes and for surveillance needs.649 33 - PublicationOpen AccessSeismic-induced accelerations detected by two parallel gravity meters in continuous recording with a high sampling rate at Etna volcano(2008-02)
; ; ; ; ; ; ;Greco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Carmisciano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Del Negro, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Loretti, I.; ENI S.p.a. ;Sicali, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Stefanelli, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; We analyse a microgravity data set acquired from two spring LaCoste & Romberg gravity meters operated in parallel at the same site on Etna volcano (Italy) for about two months (August – September 2005). The high sampling rate acquisition (2Hz) allowed the correlation of short-lasting gravity fluctuations with seismic events. After characterizing the oscillation behavior of the meters, through the study of spectral content and the background noise level of both sequences, we recognized fluctuations in the gravity data, spanning a range of periods from 1 second to about 30 seconds dominated by components with a period of about 15 ÷ 25 seconds, during time intervals encompassing both local seismic events and large worldwide earthquakes. The data analyses demonstrate that observed earthquake-induced gravity fluctuations have some differences due to diverse spectral content of the earthquakes. When local seismic events which present high frequency content excite the meters, the correlation between the two gravity signals is poor (factor < 0.3). Vice versa, when large worldwide earthquakes occur and low frequency seismic waves dominate the ensuing seismic wavefield, the resonance frequencies of the meters are excited and they react according to more common features. In the latter case, the signals from the two instruments are strongly correlated to each other (up to 0.9). In this paper the behaviors of spring gravimeters in the frequency range of the disturbances produced by local and large worldwide earthquakes are presented and discussed.296 617
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