Scuderi, Luciano

Nel 2018 è stato avviato il progetto FOCUS - Fiber Optic Cable Use For Seafloor Studies Of Earthquake - coordinato da Marc-André Gutscher del Laboratoire Géosciences Océan dell’Università di Brest, in Francia. Questo progetto indaga la sismicità e la struttura crostale del Mar Ionio attraverso l’analisi e l’interpretazione di dati raccolti da strumentazione sottomarina e da reti di monitoraggio disponibili o appositamente installate nelle zone di costa. In tale contesto, l’Osservatorio Nazionale Terremoti (ONT) e l’Osservatorio Etneo (OE), entrambe Sezioni dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV), e il Laboratorio di Sismologia dell'Università della Calabria (UniCal), hanno contribuito al progetto con l’installazione di una rete sismica temporanea lungo la costa ionica calabro-siciliana a integrazione della rete permanente presente nell’area dello Stretto di Messina. La rete temporanea, costituita da 13 stazioni, ha acquisito dal mese di dicembre 2021 al mese di giugno 2023. Nel gennaio 2022, i partner internazionali del progetto FOCUS hanno installato una rete temporanea di sismometri OBS e sensori di pressione per fondali marini. La grande quantità di dati raccolta e la loro integrazione, consentirà di migliorare il monitoraggio sismico e le conoscenze relative alla struttura terrestre dell’area con particolare attenzione alle strutture sismogenetiche con un dettaglio mai raggiunto fino a ora. Tutte le istituzioni coinvolte in FOCUS collaborano per l’acquisizione e l’elaborazione dei dati, l’imaging dell’interno della Terra attraverso l’utilizzo di tecniche avanzate, l’interpretazione e la modellazione dei dati. Il presente lavoro descrive la progettazione, la realizzazione e la gestione della rete temporanea a terra definita FXland, fornendo indicazioni relative sul suo generale funzionamento e sulle caratteristiche del dataset acquisito.

In the frame of FocusX2 project INGV (Osservatorio Nazionale Terremoti and Osservatorio Etneo) and UniCal (Laboratorio di Sismologia) are deploying, from the end of 2021 to January 2023 a temporary seismic network for an active/passive seismological experiment to record regional and global seismicity in the Ionian Sea. The goal of this experiment is to improve the detection of seismicity in the Ionian Sea area and the accuracy of the locations; to better define the crustal structure of the region and find patterns related to fault systems. The seismicity in the area is possibly the result of two types of tectonic activity at different depths: a gently NW dipping subduction interface of the Calabrian subduction zone, and the strike-slip fault systems in the Ionian Sea, well expressed in the morpho-bathymetry and observed in previous seismic profiles. The deployment of 13 temporary land stations, FocusX temporary land (network code 1J) https://doi.org/10.13127/SD/O5QWM6WJCD along the coasts of eastern Sicily and SW Calabria, is going to complement the permanent networks (network codes IV, MN and IY); in the same period OBS stations are deployed at sea: FocusX temporary OBS-network (network code XH). The land stations are equipped with two different type of digitizers: Reftek 130 (12), and SaraSL06 (2); and with three different type of velocimeters: Trillium 120C (10), Le 5s (2) and ss08 60s (2). Continuous data are transmitted in real time at the INGV Rome acquisition system, used in the seismic surveillance, archived and distributed in EIDA https://eida.ingv.it/it/. In the deployment period 23rd December 2021 - 9th May 2022 regional seismicity (area between Lat 36.5-38.2 Lon 14.5-16.0) include 390 events located by the INGV seismic surveillance system, two of them with magnitude larger than 4.0 as well as 56 teleseismic earthquakes with magnitude larger than magnitude 6.0, two of them larger than 7.0. The two local events with M>4.0 and some of their aftershocks, were analyzed by the analysts of the Italian Seismic Bulletin including all the stations of the FXland 1J network.

A sector of the San Marco Hospital (Catania, Italy) was the subject of a jacking test in order to demonstrate the substitutability of the seismic isolator. A monitoring system, included tiltmeters and strain gauges, was applied to one column. Two distinct behaviours have been identified during the unloading stage, the first in which the column and the roof are still attached and a second in which the detachment takes place. The jacking system caused the column to return to its original position, induced by the building structure for thermoelastic causes.

In recent years, seismological studies in Antarctica have contributed plenty of new knowledge in many fields of earth science. Moreover, acoustic investigations are now also considered a powerful tool that provides insights for many different objectives, such as analyses of regional climate-related changes and studies of volcanic degassing and explosive activities. However, installation and maintenance of scientific instrumentation in Antarctica can be really challenging. Indeed, the instruments have to face the most extreme climate on the planet. They must be tolerant of very low temperatures and robust enough to survive strong winds. Moreover, one of the most critical tasks is powering a remote system year-round at polar latitudes. In this work, we present a novel seismo-acoustic station designed to work reliably in polar regions. To enable year-round seismo-acoustic data collection in such a remote, extreme environment, a hybrid powering system is used, integrating solar panels, a wind generator, and batteries. A power management system was specifically developed to either charge the battery bank or divert energy surplus to warm the enclosure or release the excess energy to the outside environment. Finally, due to the prohibitive environmental conditions at most Antarctic installation sites, the station was designed to be deployed quickly.

In the present paper we describe the on-land field operations integrated in the TOMO-ETNA experiment carried out in June-November 2014 at Mt. Etna volcano and surrounding areas. This terrestrial campaign consists in the deployment of 90 short-period portable three-component seismic stations, 17 broadband seismometers and the coordination with 133 permanent seismic station belonging to Italy’s Istituto Nazionale di Geofisica e Vulcanologia (INGV). This temporary seismic network recorded active and passive seismic sources. Active seismic sources were generated by an array of air-guns mounted in the Spanish oceanographic vessel “Sarmiento de Gamboa” with a power capacity of up to 5200 cubic inches. In total more than 26,000 shots were fired and more than 450 local and regional earthquakes were recorded. We describe the whole technical procedure followed to guarantee the success of this complex seismic experiment. We started with the description of the location of the potential safety places to deploy the portable network and the products derived from this search (a large document including full characterization of the sites, owners and indication of how to arrive to them). A full technical description of the seismometers and seismic sources is presented. We show how the portable seismic network was deployed, maintained and recovered in different stages. The large international collaboration of this experiment is reflected in the participation of more than 75 researchers, technicians and students from different institutions and countries in the on-land activities. The main objectives of the experiment were achieved with great success.

Le tecniche di telerilevamento satellitare e da terra per la stima della temperatura di anomalie termiche delle superfici vulcaniche, della loro variazione nel tempo e per individuare attività parossistiche o l’inizio di una fase di colate di lava, sono ormai entrate a far parte della sorveglianza e del monitoraggio vulcanologico [es. Francis, 1979; Geraci et al., 1985; Lombardo et al., 2011; Spampinato et al., 2011]. I sensori in una banda spettrale dell’infrarosso quali radiometri e telecamere termiche, utilizzati in prossimità di bocche eruttive, hanno fornito cospicue quantità di dati di temperatura della superficie di corpi magmatici (colate laviche, laghi di lava, duomi lavici), plume vulcanici, fumarole, registrati a distanza di totale sicurezza [Spampinato et al., 2011]. In particolare, i radiometri, sia portatili che installati in stazioni permanenti, oltre che fornire dati da confrontare con misure geochimiche, permettono l’acquisizione di dati di temperatura ad elevata frequenza, tali da essere messi in relazione con le misure derivate da osservazioni geofisiche quali ad esempio il tremore sismico [es. Harris e Ripepe, 2007; Branan et al., 2008].In questo lavoro si descrivono i dettagli dell’installazione di una stazione radiometrica collocata nell’area sommitale dell’Etna in zona Belvedere, nel sito già utilizzato da una stazione multiparametrica (con sensori sismici e infrasonici) e denominato EBEL. Si descrivono anche la metodologia di trasmissione dati in continuo, il trattamento del dato convertito in temperatura apparente nel campo di vista del radiometro, la visualizzazione in tempo quasi reale del dato e la sua diffusione tramite WEB.

Earthquakes beneath Vulcano (Aeolian Island, Italy) are associated with fracturing (single events and sporadic swarms of low magnitude) or related to processes of the geothermal system (Montalto, 1994). This latter processes is responsible for most of the background activity, which is represented by weak events originating at shallow depth under the La Fossa cone (H<1.5 Km below sea level). In order to improved the Permanent Seismic Network (PSN) run by Catania Section of Istituto Nazionale di Geofisica e Vulcanologia (INGV-CT) by installing additional 5 broad-band stations surrounding the La Fossa crater, to. In particular, on November 2005 along the north rim of La Fossa cone, 3 digital stations were installed with an array configuration; thereafter, in spring 2007 another two stations were installed at the southern base of the cone. All the stations are currently in continual transmission with Lipari Observatory. We considered about 1200 micro-earthquakes recorded from January 2004 to July 2007 associated with fluid dynamics processes. Studying 1007 of these events, six classes of events have been recognized by visual inspection, spectral and cross correlation analyses. Three episodes of increasing occurrence accompanying geothermal and geochemical anomalies have been recorded during this time period. The improved seismic network allowed the location of 55 events with unprecedented resolution and to highlight a space distribution depending on the classes of events. The events are located in the central and south-oriental sector of the cone at 500-1000 meter b.s.l. depth and events of each class seem clustering in preferential sectors.