ALBERT

Description: Exist­-fdsn-­station is an open source software that implements the standard fdsnws/station web service, integrating the application into a native XML database containing seismic stations metadata in the StationXML file format. Through its HTTP Application Programming Interface, extended with the PUT method for writing, this software can be used as a RESTful microservice. The software is publicly available and licensed under a General Public License. This manual describes all the operational phases, from installation to distribution in a production environment, for using exist-­fdsn-­station to store a set of StationXML files and exposing them efficiently with a standard fdsnws/station webservice.

Description: Published

Description: 1-28

Description: OST5 Verso un nuovo Monitoraggio

Description: N/A or not JCR

Description: 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.

Description: Published

Description: 1-26

Description: OST1 Alla ricerca dei Motori Geodinamici

Description: OST3 Vicino alla faglia

Description: N/A or not JCR

Description: A catalogue of precisely located micro-seismicity is fundamental for investigating seismicity and rock physical properties in active tectonic and volcanic regions and for the definition of a ‘baseline’ seismicity, required for a safe future exploitation of georesource areas. In this study, we produce the first manually revised catalogue of micro-seismicity for Co. Donegal region (Ireland), an area of about 50K M2 of on-going deformation, aimed at localizing natural micro-seismic events occurred between 2012 and 2015. We develop a stochastic method based on a Markov chain Monte Carlo (McMC) sampling approach to compute earthquake hypocentral location parameters. Our results indicates that micro-seismicity is present with magnitudes lower than 2 (the highest magnitude is 2.8).The recorded seismicity is almost clustered along previously mapped NE-SW trending, steeply dipping faults and confined within the upper crust (focal depth less than 10 km). We also recorded anthropogenic seismicity mostly related to quarries' activity in the study area.

Description: Published

Description: 62-76

Description: OST1 Alla ricerca dei Motori Geodinamici

Description: JCR Journal

Description: Over the years, seismic anisotropy characterization has become one of the most popular methods to study and understand the Earth’s deep structures. Starting from more than 20 years ago, considerable progress has been made to map the anisotropic structure beneath Italy and the Central Mediterranean area. In particular, several past and current international projects (such as RETREAT, CAT/SCAN, CIFALPS, CIFALPS-2, AlpArray) focused on retrieving the anisotropic structure beneath Italy and surrounding regions, promoting advances in the knowledge of geological and geodynamical setting of this intriguing area. All of these studies aimed at a better understanding the complex and active geodynamic evolution of both the active and remnant subduction systems characterising this region and the associated Apennines, Alps and Dinaric belts, together with the Adriatic and Tyrrhenian basins. The presence of dense high-quality seismic networks, permanently run by INGV and other institutions, and temporary seismic stations deployed in the framework of international projects, the improvements in data processing and the use of several and even more sophisticated methods proposed to quantify the anisotropy, allowed to collect a huge amount of anisotropic parameters. Here a collection of all measurements done on core refracted phases are shown and used as a measure of mantle deformation and interpreted into geodynamic models. Images of anisotropy identify well-developed mantle flows around the sinking European and Adriatic slabs, recognised by tomographic studies. Slab retreat and related mantle flow are interpreted as the main driving mechanism of the Central Mediterranean geodynamics.

Description: Published

Description: SE215

Description: OST1 Alla ricerca dei Motori Geodinamici

Description: JCR Journal

Description: The seismic monitoring of the national territory and of the EuroMediterranean area makes use of the velocimetric, accelerometric and GPS (geodetic) data acquired by the stations of the National Seismic Network, by the RING Network and by the MedNet Network. As part of the FISR 2017 project “Integrated operating rooms and monitoring networks for the future: INGV 2.0” (2017), sensors capable of detecting both geophysical and geochemical parameters at the same time are being integrated. This technical report describes the integration of a Rn222 sensor (radon hereafter). Over the past few decades radon has found a variety of Earth Science applications, ranging from its use as a potential earthquake precursor and tectonic stress indicator to its specific role in volcanic environments, where significant changes in concentration previous or concomitant to eruptive crises are also induced by volcanic gases, CO 2 for example, which act as carriers accelerating the migration of radon through the earth’s crust and therefore its detection. In order to explore the possibility of a link between seismogenic processes and temporal variability of radon emissions, a permanent national network has been created, IRON (Italian Radon mOnitoring Network), which uses both commercial radon instruments, equipped with a proprietary system for data storage, transmission and consultation, and INGV sensors that need an interface to acquire and make data available remotely. A hardware and software interface has therefore been designed, built and tested capable of i) counting and storing the pulses in TTL format generated by the instrument which measures the 8 radon concentration in air, ii) being connected to a router for sending the acquired data to a server. A service (syncproc) was also created in PHP to query remote stations at regular intervals and collect the acquired data intended to populate a database created with MariaDB. An expressly created website allows to extract the stored data from the database and configure each installed sensor. The various software elements have been designed using open source resources.

Description: Published

Description: 3-18

Description: OST5 Verso un nuovo Monitoraggio

Description: N/A or not JCR

Description: The “Giornata ONT 2023” arises from the will to let know within INGV how many activities do people from the Osservatorio Nazionale Terremoti (ONT), and how strong is their contribution to the INGV missions: Research, Services, Education, Communication. In the nearly seven years of the current management the ONT has experienced a continuous evolutionary, sometimes complex, path. But it is always a straight path to pursue the objective of a continuous growth of the ONT. During these years the ONT has changed its name (from Centro Nazionale Terremoti – CNT, to ONT); it has experienced the coming out of some employees that moved to create the Irpinia new Section; it has lived the novelty of incoming people (example from the Centro Allerta Tsunami). It has also faced the need to overcome the limitations due to the worldwide pandemic emergency COVID19, either for the h24 services or for the research activities. Therefore in 2020 and 2021 we have only remotely attended the ONT days. The drive to be “in presenza” comes from this latter issue. We strongly want to meet, to talk face to face, to “Welcome” the young colleagues who are the injection of new ideas and perspectives, that are the necessary fuel to evolve the knowledge. As a matter of fact it emerges from the DNA of the ONT, i.e. the inclusiveness and the multidisciplinarity. This latter is widely testified by the ONT activities that are shared among the three Departments and their strategic objectives. The agenda of the “Giornata ONT 2023” has specifically emphasized the variety of the technical and scientific contents, that for sake of simplicity have been collected in the following themes: • Infrastructures, Data­Sharing and Laboratories • Analysis, Modelling, Interpretation of Geophysical Phenomena • National and International Projects (Research Results and Products from Completed Projects; Ongoing Projects) • Society ­ Communication, Dissemination, Emergency Management • Seismic Surveillance And Tsunami Warning Overall, the contributions have been 100, most of which are posters (77) and the remaining (23) in different exhibit formats. The wide interest about the proposed contents and the positive feedback from the attendance, pushed the decision to collect and publish the contributions in a Miscellanea INGV, where the documents can be easily found. And we are finally ready to make the Miscellanea available to the reader. I would warmly thank the Authors for their enthusiastic acceptance to contribute, the Conveners of the “Giornata ONT 2023” Sessions for their availability to organise and manage the submitted poster/exhibits, the Editorial Board members for their hidden work that led to this Miscellanea. In conclusion, let me spend a few words about my personal journey as Director of the ONT. After 2504 days it has come to an end and the “Giornata ONT 2023” and the Miscellanea are, somehow, the cherry on top. It is really difficult to say “Thanks” one by one to the people who helped me along this complex and long path. So, please, let me simply say Grazie a tutti voi! Salvatore Stramondo - Director ONT (2017-2023)

Description: Published

Description: 1-206

Description: N/A or not JCR

Description: This work was carried out within the 2015 ART-IT project (Early Earthquake Alert in ITaly). Its main purpose is to investigate the performance and the critical issues of an early warning system with particular reference to the PRESTo system (PRobabilistic and Evolutionary early warning SysTem, [Iannacone et al., 2010; Satriano et al., 2011]) whose use has been tested in the framework of the above mentioned project. The correct operation of an early warning system can effectively guarantee a more effective management of a seismic emergency from the first seconds after the occurrence of a strong earthquake, allowing quick actions to reduce exposure and seismic risk. The work was substantially subdivided into two main steps. A first calibration phase, carried out in the first part of the project and aimed to identify the best values of the software configuration parameters in terms of event triggering and declaration. Once the values of the aforementioned parameters have been identified, the second phase of the work was focused on testing the software in real time configuration, on a test site area and the subsequent evaluation of its performance in terms of declaration and localization capacity. This work focuses mainly on the second part of the experimentation and is aimed describing and summarizing the analysis carried out to evaluate the response of the PRESTo software (and in general of an early warning system) after one year of experimentation and acquisition and highlight any problems and critical issues of the software and more generally of the rapid alert systems.

Description: Published

Description: 1-32

Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami

Description: JCR Journal

Description: This paper is intended as a short presentation of the main limitations affecting seismic hazard assessment, revisiting possible methods available in the literature to be applied for this purpose. The convergence of the African Plate with the Eurasian Plate is the cause of the high seismic activity characterizing the Mediterranean region, with particular intensity in its eastern part. It is clear that the associated seismic risk requires appropriate measures for its mitigation. Seismic risk, the amount of resources that the community is expected to pay to earthquakes in the long term, is the product of three factors, such as seismic hazard, vulnerability and value of the exposed goods. As earthquakes cannot be prevented, seismic risk can be mitigated by improving our knowledge of seismic hazard, which is largely based on statistical analysis of historical earthquake catalogs. Nevertheless, historical records are affected by problems of reliability, completeness and shortness, as they commonly span time lengths of the same order of magnitude or even shorter than the inter-event time of the strongest earthquakes produced by specific seismic sources. In this respect, alternative methods can be proposed for integrating and improving our knowledge of seismogenic processes, and estimating both time-independent and time-dependent occurrence rates of strong earthquakes. We propose the application of physics-based earthquake simulators, requiring the knowledge of a robust geological-geophysical seismogenic model.

Description: In press

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: This report describes the state of the art of the installation techniques for seismic stations developed by the Seismology Group and the Seismology Laboratory at the INGV branch in Pisa, with examples of applications taken from long‐duration field experiments carried out in different areas of Tuscany, such as Monte Amiata and the Mugello basin. Our goal was to develop a low‐cost infrastructure, portable and easily adaptable to different terrains, suitable for hosting a variety of real‐time seismic stations. In addition to improving the structural resistance of the deployment, we also developed applications for the remote monitoring of the state of health of the seismic stations, which allowed a more efficient maintenance of the instrumentation. The proposed type of installation has proved to be sufficiently robust and suitable for installations with a temporal duration of a few years, and in agreement with the expected targets, as proved by the analyses carried out during and at the end of the experiments in which they were used.

Description: Published

Description: 1-30

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: N/A or not JCR

Description: Nel mese di maggio 2022 è iniziato uno sciame sismico, di breve durata, che ha interessato una piccola area del Chianti fiorentino a circa 15 km a sud dalla città di Firenze. I due terremoti più energetici hanno avuto una magnitudo momento pari a 3.7; nonostante la magnitudo modesta, tali eventi sono stati avvertiti distintamente fino a distanze di diverse decine di chilometri, e hanno destato preoccupazione nella popolazione prossima all’area epicentrale. Inoltre, dato l’ingente patrimonio artistico presente nel capoluogo toscano, questo episodio ha sollevato interrogativi sulla sua vulnerabilità anche a scuotimenti del suolo di piccola entità. Al fine di migliorare le conoscenze sulla ubicazione e le dimensioni delle strutture sismogenetiche attive in prossimità di Firenze, l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) è intervenuto nell’area interessata dallo sciame attraverso il Gruppo Operativo (GO) di emergenza SISMIKO. Il 4 maggio, giorno successivo all’inizio dello sciame, cinque stazioni sismiche mobili sono state installate a distanza ravvicinata dall’area epicentrale, e integrate nel sistema di monitoraggio permanente INGV. Questo lavoro descrive le procedure relative a: (i) l’installazione, la manutenzione e la disinstallazione della rete sismica mobile; (ii) la gestione e il controllo di qualità dei dati acquisiti. Infine, vengono presentate, in riferimento al contesto sismotettonico dell’area, le caratteristiche spaziali e l’evoluzione temporale dello sciame, che ha presentato una piccola ripresa nell’attività sismica ad agosto del 2022, con un terremoto di magnitudo locale 2.7 e successive repliche.

Description: Published

Description: 1-26

Description: OST5 Verso un nuovo Monitoraggio

Description: JCR Journal

Description: The latest version of the CPTI15 seismic catalogue (January 2022) includes more than two hundred earthquakes marked AMGNDT95. Their parameters are derived from expeditious studies produced as part of the GNDT/CNR ‘Hazard Project’ (1993-1995). Some of them simply parameterise data taken from bibliographic references in the PFG85 catalogue, i.e., mostly Mario Baratta’s seismological compilation “I terremoti d’Italia” [1901] or twentieth-century seismological bulletins. Others go back as far as the original sources of the references themselves. As part of the B2 Convention between INGV and DPC (2016-2021), a review of these earthquakes was initiated, starting with the most relevant ones, for which a good margin of improvement in knowledge can be assumed. At the same time, first-level research was also begun on a dozen or so earthquakes of low energy, but still above the damage threshold, which for various reasons had never been studied so far and whose parameters in the CPTI15 are still those of the POS85 catalogue. We present here the results of the study of about thirty earthquakes belonging to both categories. The overall result is generally a strong improvement of the available information, from which it will be possible to derive epicentral parameters more up-to-date and more robust than the previous ones.

Description: Questo lavoro è stato realizzato nell’ambito della Convenzione fra INGV e Dipartimento nazionale della Protezione Civile, Allegato B2.

Description: Published

Description: 1-260

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Mobile network routers in seismic and volcanic surveillance

Description: Published

Description: 1-36

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: N/A or not JCR

Description: This text is an introduction to the problem of low frequency electromagnetic monitoring, with particular emphasis on VLF band. All related issues have been addressed: from historical outlook to numerical analysis, from seismology to geotechnics, electronics, information technology. The approach is informative and didactic. This interdisciplinary approach does not imply a problem of skills to the reader, and my goal has been to complete each specific cultural background. Geophysics is a topic where different training paths converge, usually geological or physical. In this case, addressing also technical aspectcts, it is not really possible to setup a guide for a specific professional figure. For this reason, while some topics will be new, others instead will inevitably seem trivial or superficially addressed. The reality is that every topic, as far as possible, has been treated on the same level. When necessary, an appendix to the text will offer further specific insights from time to time.

Description: Questo testo vuole essere un’introduzione alle problematiche del monitoraggio elettromagnetico a bassa frequenza, con particolare approfondimento sulla banda VLF. Vengono affrontate tutte le tematiche correlate, dall’analisi storica all’analisi numerica, dalla sismologia alla geotecnica, all’elettronica, all’informatica. L’impostazione è divulgativa e didattica. L’approccio interdisciplinare non porrà al lettore un problema di competenze, anzi l’obiettivo è quello di completare ogni specifico bagaglio culturale. La geofisica è già un argomento in cui convergono percorsi formativi diversi, solitamente di impostazione geologica o fisica. In questo caso, in cui si affronta anche un aspetto tecnico, non è proprio possibile indirizzare una guida a una specifica figura professionale. Per questo motivo, mentre alcuni argomenti risulteranno nuovi, altri inevitabilmente appariranno scontati o forse affrontati superficialmente. La realtà è che ogni tematica, per quanto possibile, è stata affrontata allo stesso livello. All’occorrenza, un’appendice offrirà di volta in volta ulteriori approfondimenti specifici.

Description: Progetto INGV “Pianeta Dinamico” (codice progetto INGV 1020.010) finanziato dal MIUR ("Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese", legge 145/2018).

Description: Published

Description: 1-142

Description: 7T. Variazioni delle caratteristiche crostali e "precursori"

Description: N/A or not JCR

Description: We present here the results of a five-years-long earthquake educational project aiming to commemorate the hundredth anniversaries of five large Northern Apennines earthquakes occurred between 1916 and 1920 in the areas of: Rimini (1916, Mw 6.1), Valtiberina (1917, Mw 5.9), Romagna Apennines (1918, Mw 5.9), Mugello (1919, Mw 6.3) and Garfagnana (1920, Mw 6.5) earthquakes. We saw these anniversaries as the occasion for leading the Northern Apennines people to rediscover their past, in a positive way, and to improve their awareness of the earthquake as a natural feature of the regions in which they live. The activities that we planned for schools students encouraged them to go hunting for traces of the earthquakes of one hundred years ago in their home towns and to rediscover the memories and traditions of their communities. Together with their teachers, we also led the teenagers to find creative ways to involve the grownups in the process of discovery and knowledge. The Project had to cope with two emergencies: the great Central Italy earthquake of 2016-2017 and the Covid-19 epidemic. However, these stumbling blocks did not deter teachers and students from taking part in the process actively and even enthusiastically. Their families and communities were actively involved too. This experience taught us some valuable lessons. First of all, we learned to adapt the project, as we had conceived it at the start, to a wide gamma of social and cultural contexts. Not all the involved communities were equally aware of the level of seismic risk they are exposed to. On the affluent Adriatic coast, where tourism is the main source of income, past earthquakes are something best forgotten, by citizens and administrators alike. On the contrary, in the poorer inland mountain areas (Forlivese Apennines, Mugello, Garfagnana and Lunigiana) a more down-to-earth attitude prevails: earthquakes are looked upon as something that can and does happen and people are quick to grasp how important it is to contribute to initiatives whose aim is reducing seismic risk. Thus, we had to adapt our approach to the different contexts, modifying each time the activities we proposed to the schools with the aim of obtain the best possible results from each situation. Presentiamo i risultati di un progetto di educazione al rischio sismico attivato in occasione dei centenari di cinque terremoti storici che hanno colpito l’Appennino settentrionale tra gli anni 1916 e 1920 e precisamente i terremoti di Rimini 1916 (Mw 6.1), Valtiberina 1917 (Mw 5.9), Appennino romagnolo 1918 (Mw 5.9), Mugello 1919 (Mw 6.3) e Garfagnana 1920 (Mw 6.5). Abbiamo pensato di utilizzare questi anniversari come punto di partenza per accompagnare i cittadini a riappropriarsi del loro passato in modo positivo, facendo crescere la loro consapevolezza del terremoto come un carattere del loro ambiente naturale. A tal fine, nelle attività realizzate con le scuole, abbiamo incoraggiato gli studenti a cercare le tracce dei terremoti di un secolo fa nell’ambiente urbanizzato e a indagare le memorie e le tradizioni ancora presenti nelle comunità. Insieme ai loro insegnanti abbiamo spinto i ragazzi a trovare modi creativi per coinvolgere gli adulti in questo processo di scoperta e conoscenza. Il progetto è stato messo alla prova dal forte terremoto dell’Italia centrale (2016­2017) e dall’epidemia di Covid­19, ma nonostante queste difficoltà insegnanti e studenti hanno partecipato con grande interesse a questo percorso e hanno coinvolto nelle attività del progetto le famiglie e le comunità locali. Anche noi abbiamo imparato nuove lezioni. Un aspetto importante che abbiamo appreso è il bisogno di adattare il progetto a contesti sociali e culturali che si sono rivelati molto diversi. Le comunità coinvolte non condividono lo stesso livello di consapevolezza del rischio: sulla costa adriatica, a vocazione turistica, i terremoti sono qualcosa che è meglio dimenticare, sia da parte dei cittadini che dalle amministrazioni. Al contrario, nell’Appennino forlivese, nel Mugello, in Garfagnana e Lunigiana, i terremoti sono una presenza costante e le persone si sono sentite subito coinvolte in un processo attivo di riduzione del rischio e di attenzione quotidiana. Questo ci ha spinto ad adattare ogni volta l’approccio ai diversi contesti, modificando le proposte di attività che abbiamo realizzato nelle scuole.

Description: Lavoro realizzato nell’ambito della Convenzione fra INGV e Dipartimento della Protezione Civile, Allegato A, tematica “M”.

Description: Published

Description: 1-40

Description: 5SR TERREMOTI - Convenzioni derivanti dall'Accordo Quadro decennale INGV-DPC

Description: JCR Journal

Description: In Italy, historical research on earthquakes has a long and glorious tradition, which in recent decades has gone through very different phases. In the first half of the 1980s and up to the mid- 90s, two very demanding research ventures were developed: the research program financed by ENEL for the qualification of sites susceptible to nuclear plants in three areas of the country (Piedmont, Lombardy, Puglia), later merged into the “Catalog of Strong Italian Earthquakes” (CFTI) of the ING/INGV, and the “Hazard project” of the GNDT/CNR, aimed at preparing all the basic data necessary for a model of hazard updated. As part of these two ventures, for about a decade over a hundred researchers, mostly “professional” historians, have worked to update their knowledge of Italian historical earthquakes. Researches developed by the “Hazard Project” - complementary to those of the CFTI - aimed only at rapidly re-evaluating the knowledge on about 600 intermediate energy earthquakes. Some of these studies, after a couple of decades, are now largely obsolete. For this reason, a work plan was launched aimed at deepening the knowledge on several dozens of these studies, marked in the current Parametric Catalog of Italian Earthquakes (CPTI15) by the initials AMGNDT95, providing them with an updated and, hopefully, better database. This work presents the results of research carried out on 6 earthquakes included in the 1949– 1971 time span. Such researches have allowed a significant improvement of the epicentral parameters of these earthquakes and, at the same time, an enhancement of seismic histories of numerous localities.

Description: Lavoro realizzato nell’ambito della Convenzione fra INGV e Dipartimento nazionale della Protezione Civile, Allegato B2.

Description: Published

Description: 1-274

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Questa è una traduzione commentata del raro documento citato da oltre un secolo di bibliografia come “Milne, 1890”. Si è studiato il testo per verificare la realisticità di alcune recenti affermazioni sul fatto che questo rapporto (oggi difficilmente reperibile) avesse trattato per la prima volta di precursori elettromagnetici. Si è cercato di indagare su ogni episodio e personaggio, identificando i criptici (e a volte inesistenti) riferimenti bibliografici, rintracciando quasi tutti i testi, ampliando e commentando spesso le relative citazioni. La mia opinione è che nessuno all’epoca di Milne avesse consapevolmente, ma forse nemmeno accidentalmente, osservato un precursore di origine elettromagnetica. I fenomeni descritti sono studiati da un punto di vista puramente elettrico o magnetico. I segnali elettrici riguardano tensioni e correnti troppo alte. I fenomeni magnetici già all’epoca furono contestati come prodotti di effetti inerziali ma comunque è difficile pensare che la componente campo magnetico di un segnale EM possa deviare stabilmente l’ago di una bussola. Questa stessa ricerca ha tuttavia portato alla luce qualche altro caso sospetto che sarebbe opportuno indagare in modo più approfondito, in quanto potrebbe risultare realmente il primo caso documentabile dell’osservazione di un precursore elettromagnetico del terremoto.

Description: This is a commented translation of the rare document cited by more than a century of bibliography as "Milne, 1890". The text was studied to verify the veracity of some recent claims that this report (presently difficult to find) had dealt with electromagnetic precursors for the first time. An attempt was made to investigate each episode and character, identifying the cryptic (and sometimes non-existent) bibliographic references, tracing almost all the texts, often expanding and commenting on the relative citations. My opinion is that no one, at the time of Milne, had consciously, but maybe not even accidentally, observed a precursor of electromagnetic origin. The phenomena described are studied from either a purely electrical or magnetic point of view. Electrical signals concern too high voltages and currents. Magnetic phenomena, already at the time, were contested as products of inertial effects, but in any case it is difficult to think that the magnetic field component of an EM signal can permanently deflect the needle of a compass. However this same research has brought to light some other potentially interesting cases that should be investigated further. One of them, could actually be the first documentable case of the observation of an electromagnetic seismic precursor.

Description: Progetto INGV “Pianeta Dinamico” (codice progetto INGV 1020.010) finanziato dal MIUR ("Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese", legge 145/2018).

Description: Published

Description: 1-48

Description: 2TM. Divulgazione Scientifica

Description: JCR Journal

Description: The Western Ionian Sea is characterised by an active and diffuse seismicity, directly related to the convergence of the European and African Plates and by gravitational sinking and rollback of the oceanic lithosphere. In this area, the location of earthquakes is characterised by considerable uncertainties due to large azimuthal gaps, resulting in notable location errors. This problem was partially overcome with the use of data recorded by NEMO-SN1 seafloor observatory (October 2002 - February 2003; June 2012 - May 2013). We relocated 1130 crustal and sub-crustal earthquakes using land network and NEMO-SN1 data. As most events occurred on Mt. Etna, we focused on 358 earthquakes in the offshore area and near the coasts of Sicily and Calabria. The use of the combined land-marine networks has improved the earthquake locations in terms of azimuthal GAP, as well as in horizontal and vertical errors. The comparison between locations performed with and without NEMO-SN1 data shows that differences in latitude, longitude and depths are more evident in the Western Ionian Sea and in the coast of Sicily, where values of the differences over 5 km correspond to structural heterogeneities. The increased number of seismic stations deployed on land from 2003 to 2012 did not influence the location of events occurring offshore, where NEMO-SN1 continued to be the distinctive tool in the location process. Moreover, the new 73 focal mechanisms computed with P-wave polarities from NEMO-SN1 and land stations are in agreement with the regional structural model, showing a prevalent normal, normal/oblique, and strike-slip kinematics. The similarity of two new focal solutions with the mechanisms of the main shock and aftershock of the 1990 earthquake demonstrates that the seismic structures are still active and potentially dangerous. The P-wave travel time residual analysis confirms the activity along the main structural alignments. A single point of observation in the Ionian Sea can significantly improve the quality of locations, giving an opportunity to focus on the seismogenic structures responsible for the occurrence of medium-to-high magnitude earthquakes.

Description: Published

Description: Se655

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: The present paper describes the process of moving from a research study of most common vulnerable non-structural elements, to deliver solutions, tools and guidelines to improve understanding of and responsiveness to community concerns about seismic risk and non-structural elements. The observed damage to non-structural elements following recent earthquakes in Italy, Portugal and Iceland, were used for designing communication tools under the KnowRISK EU project for multi-stakeholders (students, business and citizens): the Practical Guide, the Students Short Guide, the KnowRISK Portfolio of Solutions, the Move, Protect and Secure video, the augmented reality apps, the maquettes, the students notebooks, videos, board games and hands-on tools. The philosophy behind these deliverables is that some risks, once identified, can be eliminated or reduced by informing people and suggesting preventive or emergency measures. These tools are devoted to improving the seismic performance of non-structural elements and to reduce the associated economic losses, loss of functionality, and potential threats to life safety. The rationale behind the selection of the information that people need to know for converting knowledge to more safety is discussed and a description of the transference of the findings of research to communication solutions is presented. The tools were planned following the engagement-model in risk communication to ensure that needs of communities and selected stakeholders were acknowledged, and that recipients are addressed in a way that appeals to them. Different media and communication channels such as print, television, online, face-to face communication and interviews were used for risk communication.

Description: This study was co-financed by the European Commission’s Humanitarian Aid and Civil Protection (Grant agreement ECHO/SUB/2015/718655/PREV28).

Description: Published

Description: SE322

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: This simple and qualitative discussion is an attempt to include in a comprehensive framework the problem of earthquake forecasting and univocally clarify the meaning of "precursor" and the true importance of their study. It is also the starting point to present the potential of the electromagnetic precursor in the framework of classic precursors. The fact that seismic precursors are truly existing phenomena does not represent the solution to the problem of deterministic forecasting. Currently a precursor is not a prediction aid but an investigative tool of the earthquake preparation process: aka the complex mechanism of microfracturing, growth and self-organization of fractures that is necessary to produce ruptures in the crust. Scholz's "Theory of Dilatance" (ToD), improved and further developed for decades after 1960, remains one of the best explanations for the existence of observable precursors and still seems to highlight the only plausible common cause. ToD is presented here in an "extended" vision in the framework of geotechnical knowledge on rock fracturing in the laboratory. Dilatance is a systematic and necessary process with respect to rock breaking. It would itself be the ideal precursor to the earthquake if it did not lack the essential characteristic of being directly observable. At the moment, the only way to detect dilatance in nature is through its interaction with the surrounding environment and its ability to change the physical characteristics of the rock, that is, through secondary phenomena that it can cause. These phenomena sometimes visible on the surface are what we call precursors. We have reviewed the main "classic" precursors by examining them in the light of the ToD. The study of dilatance, which requires a comparative, systematic and extensive monitoring of precursor phenomena, could lead to a key of interpretation of the precursors themselves for the prediction of the earthquake.

Description: Questa trattazione divulgativa è un tentativo di presentare il problema della previsione dei terremoti nella sua globalità per chiarire il significato di “precursore” e la vera utilità dello studio dei precursori. È anche lo spunto per presentare al pubblico le potenzialità del precursore elettromagnetico nel panorama dei precursori classici. Il fatto che i precursori sismici siano fenomeni realmente esistenti non rappresenta la soluzione al problema della previsione deterministica. Attualmente un precursore non è uno strumento di previsione ma un mezzo di sondaggio di ciò che chiamiamo “preparazione del sisma”: il complesso meccanismo di microfratturazione, accrescimento e autoorganizzazione delle fratture che è necessario a produrre la rottura nella crosta. La “teoria della Dilatanza” (TdD) di Scholz, più volte perfezionata dal 1960 ad oggi, resta una delle migliori trattazioni invocabili per motivare l’esistenza dei precursori documentati e sembra tuttora restare l’unica plausibile forma di inquadramento comune. Essa viene qui ripresentata in una visione “estesa” alla luce delle conoscenze geotecniche sulla fratturazione della roccia in laboratorio. La dilatanza è un processo sistematico e necessario rispetto alla rottura della roccia. Sarebbe essa stessa il precursore ideale del terremoto se non mancasse della caratteristica essenziale di essere visibile. Al momento l’unico modo per rilevare la dilatanza in natura è attraverso la sua interazione con l’ambiente circostante e la sua capacità di mutare le caratteristiche fisiche della roccia, cioè attraverso fenomeni secondari che essa può causare. Questi fenomeni, talvolta visibili in superficie, sono ciò che chiamiamo precursori. Abbiamo messo in rassegna i principali precursori “classici” esaminandoli alla luce della TdD. Lo studio della dilatanza, che richiede un monitoraggio comparato, sistematico ed esteso dei fenomeni precursori, potrebbe condurre alla definizione di una chiave interpretativa comune e generale dei precursori stessi per la previsione del terremoto.

Description: Progetto INGV “Pianeta Dinamico” (codice progetto INGV 1020.010) finanziato dal MIUR ("Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese", legge 145/2018).

Description: Published

Description: 1-40

Description: 7T. Variazioni delle caratteristiche crostali e "precursori"

Description: JCR Journal

Description: probably confirm this opinion, with qualifica ons. Historical earthquake catalogues, up to CPTI11 [Rovida et al., 2011], report only one Mw 5.1 event on 13 November 1948: it was located in the Sardinian Sea, and had very modest effects on land. In later decades, the seismic networks did record very few earthquakes of moderate energy (Mw 〈5), mostly located off-shore, either south-east of Cagliari or west of Olbia or in the Sea of Sardinia. The most recent ones (occurred in 2000, 2004 and 2006) had very slight effects on the island. Given the low level of instrumental seismicity and the weak macroseismic effects of known historical earthquakes, Sardinia's seismic risk is perceived as very low. The low seismicity of the region certainly has a geological explana on, given that the Corsica-Sardinia block is among the most stable areas of the Mediterranean basin. “Low”, however, does not mean “non- existent”: recent historical research has improved knowledge on the major known historical earthquake of Sardinia (it occurred on June 4, 1616 and was responsible for minor but widespread damage to the system of coastal watchtowers, south-west of Cagliari) and rediscovered several minor earthquakes, part of which were known to the seismological tradi on but had been almost completely forgo en. This paper collects all the documenta on available at present on the seismic history of Sardinia.

Description: Published

Description: 1-160

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Questo rapporto tecnico descrive le attività svolte da SISMIKO [Moretti et al., 2012; 2016a; 2016b; Pondrelli et al., 2016] in occasione della sequenza sismica che ha interessato l’area in provincia di Campobasso tra i comuni di Montecilfone, Guardialfiera e Larino a partire dal 14 agosto 2018 e che ha visto nel terremoto di magnitudo ML 5.2 (MW 5.1) del 16 agosto 2018 (18:19 UTC), ben risentito in un’ampia area che comprende molte regioni dell’Italia centro meridionale, l’evento più significativo della sequenza. SISMIKO è uno dei gruppi operativi dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) per la gestione delle emergenze sismiche [Pondrelli et al., 2016], e come per ogni terremoto con magnitudo superiore a 5.0, ovvero alla soglia prevista nella vigente Convenzione tra l’INGV e il Dipartimento della Protezione Civile (DPC), a seguito del terremoto del 16 agosto 2018 (ML 5.2) ha predisposto un intervento volto al miglioramento del monitoraggio sismico dell’area interessata. L’integrazione di stazioni sismiche temporanee nella geometria della Rete Sismica Nazionale (RSN [Michelini et al., 2016; INGV Seismological Data Centre]), consente infatti un miglioramento nella individuazione dei terremoti e un perfezionamento del calcolo dei parametri ipocentrali, soprattutto della profondità che è strettamente connessa alla distanza media tra le stazioni sismiche. L’intervento principale è stato svolto nella giornata del 17 agosto [SISMIKO working group, 2018], ma nelle due settimane successive i siti allestiti sono stati più volte visitati e il giorno 30 si è proceduto con l’integrazione di ulteriori 2 stazioni, portando a 5 i punti di acquisizione della rete temporanea. La rete sismica è stata operativa per circa 2 mesi. I dati sono stati trasmessi in tempo reale al centro di acquisizione dati della rete mobile presso la sede di Roma di SISMIKO e al contempo integrati nel sistema di sorveglianza sismica INGV [Michelini et al., 2016] per essere utilizzati nelle localizzazioni e nei prodotti scientifici forniti in tempo reale. On 16 August 2018 at 18:19:04 UTC an earthquake with magnitude ML 5.2 (MW 5.1) occurred in the Molise region. The earthquake was felt in a large area including many regions of Central and Southern Italy. The seismologists on duty in the 24H seismic monitoring room of the National Institute of Geophysics and Volcanology (INGV) located the event in the province of Campobasso, 4 km south­east of Montecilfone and at a preliminary depth of 9 km. The same area was affected two days before by a MW 4.6 event (August 14 at 23.48 Italian time1). Following the MW 5.1 event and the associated aftershock sequence, the SISMIKO Operational Group was activated [Moretti et al., 2012; 2016a; 2016b; Pondrelli et al., 2016] for the installation of temporary seismic stations to integrate the permanent stations of the National Seismic Network (RSN [Michelini et al., 2016; INGV Seismological Data Centre]) deployed in the region.

Description: Published

Description: 1-32

Description: 2SR TERREMOTI - Gestione delle emergenze sismiche e da maremoto

Description: N/A or not JCR

Description: A seguito di un evento sismico al di sopra della soglia del danno, una parte del personale dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) viene coinvolto nei gruppi di emergenza e si prepara, nel più breve tempo possibile, a partire per raggiungere l’area epicentrale. Ogni gruppo ha il compito di raccogliere dati, effettuare misurazioni e rilievi, per studiare il terremoto sotto diversi punti di vista, e per supportare le attività di Protezione Civile. In questo contesto rientrano le attività di rilievo del gruppo QUEST (QUick Earthquake Survey Team), formato da personale specializzato nel rilievo macrosismico dell’INGV e altri enti, che ha il compito di raggiungere le aree colpite dal sisma per fornire un rilievo degli effetti sull’edificato, sull’ambiente e sulle persone. L’indagine macrosismica che ne deriva, contribuisce allo studio del terremoto attraverso l’osservazione diretta e la classificazione del danno mediante l’utilizzo della scala macrosismica EMS98 [Grünthal, 1998]. Attualmente questa indagine viene svolta con l’ausilio di schede cartacee predisposte per la raccolta del dato ed una serie di mappe, generalmente immagini da satellite, delle località da investigare [Tertulliani et al., 2010]. Nel tempo si è cercato di studiare tecniche di rilievo sempre più rapide al fine di raccogliere il dato reale del danneggiamento prima che gli inevitabili interventi di messa in sicurezza dei vigili del fuoco o ulteriori repliche dannose modifichino lo scenario del danno sull’edificato. Per questo scopo si sta mettendo a punto uno strumento per la raccolta del dato macrosismico di campagna, basato sull’utilizzo di tablets, corredati di una interfaccia grafica tale da permettere la raccolta delle informazioni direttamente su mappe delle località da investigare. In particolare, l’inserimento dell’informazione puntuale per ogni edificio investigato, con il relativo dato di vulnerabilità e grado di danno, permette di condividere le informazioni in tempo reale tra le varie squadre sul terreno. Tale strumento permette inoltre, all’operatore, di lavorare off line e quindi di poter acquisire informazioni anche in assenza di copertura del segnale telefonico e di inviare in un secondo momento i dati. L’informazione viene centralizzata presso la sede operativa che può gestire e coordinare lo spostamento delle squadre nell’area epicentrale. In questo modo si aprono nuovi interessanti scenari sia a vantaggio della rapidità e della conoscenza del danneggiamento dell’edificato, sia in termini di gestione del personale coinvolto per ottimizzare così le operazioni di rilievo.

Description: Published

Description: 1-24

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: N/A or not JCR

Description: We explore the three‐dimensional structure of the 2016–2017 Central Italy sequence using ~34,000 ML ≥ 1.5 earthquakes that occurred between August 2016 and January 2018. We applied cross‐correlation and double‐difference location methods to waveform and parametric data routinely produced at the Italian National Institute of Geophysics and Volcanology. The sequence activated an 80 km long system of normal faults and near‐horizontal detachment faults through the MW 6.0 Amatrice, the MW 5.9 Visso, and the MW 6.5 Norcia mainshocks and aftershocks. The system has an average strike of N155°E and dips 38°–55° southwestward and is segmented into 15–30 km long faults individually activated by the cascade of MW ≥ 5.0 shocks. The two main normal fault segments, Mt. Vettore‐Mt. Bove to the North and Mt. della Laga to the South, are separated by an NNE‐SSW‐trending lateral ramp of the Sibillini thrust, a regional structure inherited from the previous compressional tectonic phase putting into contact diverse lithologies with different seismicity patterns. Space‐time reconstruction of the fault system supports a composite rupture scenario previously proposed for the MW 6.5 Norcia earthquake, where the rupture possibly propagated also along an oblique portion of the Sibillini thrust. This dissected set of normal fault segments is bounded at 8–10 km depth by a continuous 2 km thick seismicity layer of extensional nature slightly dipping eastward and interpreted as a shear zone. All three mainshocks in the sequence nucleated along the high‐angle planes at significant distance from the shear zone, thus complicating the interpretation of the mechanisms driving strain partitioning between these structures.

Description: Published

Description: e2019JB018440

Description: 3T. Sorgente sismica

Description: JCR Journal

Description: “Move, protect, secure” were the three key points that the KnowRISK (Know your city, Reduce seISmic risK through non-structural elements) project posed at the core of its communication and dissemination strategy. This three key points enable each person, professional or not, to reduce non-structural damage caused by earthquakes. Dissemination is usually the last but never the least step of a communication plan, and indeed it played a crucial role in KnowRISK project for conveying the three key-point message to the widest audience. Standard dissemination activities, such as open-door events, and internet allowed us to achieve a wide spreading of ideas and best practices, reaching more than 4,000 non-professionals and almost 50,000 page views of the KnowRISK project website (in three years), respectively. As communication was recipient-targeted, the dissemination task of the project was addressed to professionals, layman, and schools. In particular, schools were chosen in order to profit from the chain-reaction action that is capable to spread a message from students to the surrounding environment.

Description: This study was co-financed by the European Commission’s Humanitarian Aid and Civil Protection through the European project KnowRISK (Know your city, Reduce seISmic risK through non-structural elements; Grant agreement ECHO/SUB/2015/718655/PREV28).

Description: Published

Description: SE328

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: Different procedures were used to analyze a comprehensive time series of nighttime thermal infrared images acquired from October 2006 to June 2013 by a permanent station at Pisciarelli (Campi Flegrei, Italy). The methodologies were aimed at the detection and quantification of possible spatiotemporal changes in the ground-surface thermal features of an area affected by diffuse degassing. Long-term infrared time series images were processed without taking into account atmospheric conditions and emissivity estimations. The data obtained were compared with the trends of independent geophysical and geochemical parameters, which suggested that long-term temporal variations of the surface maximum temperatures were governed by the dynamics of the deeper hydrothermal system. Analogously, the dynamics of the shallow hydrothermal system are likely to control the short-period thermal oscillations that overlie the long-term thermal signals. The map of the yearly rates of temperature change shows temperature increases clustered in the thermal anomalous area of the infrared images, without evidence of modifications to the extension of the anomaly or of growth of new areas with significant thermal emission. This suggests that in the present state, the heat transfer is mainly due to hot gas emission through preexisting fractures and vents. Our data indicate that the comprehensive picture of the spatiotemporal evolution of the thermal features of the hydrothermal sites obtained by long-term infrared monitoring can provide useful information toward refining physical and conceptual models, as well as improving surveillance of active volcanoes.

Description: The TIR monitoring system was partially funded by the 2000–2006 National Operating Programme and by the Italian Civil Protection Department in the framework of the 2004–2006 agreement with the Istituto Nazionale di Geofisica e Vulcanologia.

Description: Published

Description: 812–826

Description: 2V. Dinamiche di unrest e scenari pre-eruttivi

Description: 5V. Sorveglianza vulcanica ed emergenze

Description: JCR Journal

Description: restricted

Description: La rivista non prevede l'Abstract e inizia direttamente dall'Introduzione, che viene sotto riportata. In ambiente vulcanico, al fine di monitorare e studiare l’azione delle sorgenti, è di fondamentale importanza riuscire a misurare con estrema precisione l’espansione/contrazione del mezzo. Questo è ottenibile attraverso l’utilizzo di strumenti noti come borehole strainmeters (o dilatometri da pozzo). Lo strumento di base e' da un punto di vista teorico abbastanza semplice. Consiste di un tubo cilindrico, al suo interno riempito di specifico fluido (solitamente olio di silicone), da installare in un foro appositamente trivellato ponendolo in contatto con le pareti rocciose del foro attraverso l’utilizzo di cementi ad espansione, che consentono un perfetto accoppiamento strumento-mezzo. La variazione di livello del fluido indotta dalla variazione dello strain nel mezzo circostante è quindi misurata con estrema precisione attraverso un apposito sensore. I dilatometri da pozzo sono gli strumenti più sensibili alle variazioni dello stato degli sforzi finora realizzati a fini geofisici (sensibilità nominale dV/V fino a 10-12). La tipologia di strumentazione utilizzata nelle installazioni all’Etna è quella nota come Sacks-Evertson borehole strainmeters (o dilatometers) [Sacks et al., 1971]. Le principali caratteristiche tecniche della strumentazione sono riportate in tabella 1. Gli strainmeters e l’elettronica di controllo sono prodotti dal Department Terrestrial Magnetism (DTM) del Carnegie Institution di Washington. I colleghi del DTM sono presenti alle fasi finali d’installazione e di avvio dell’operatività strumentale.

Description: Published

Description: 1-25

Description: 5V. Sorveglianza vulcanica ed emergenze

Description: N/A or not JCR

Description: open

Description: In the past, variations in the chemical contents (SO4 2−, Cl−, cations) of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity) should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes), taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area), lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf - kg/s) –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated) Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes.

Description: Published

Description: 161-173

Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Description: JCR Journal

Description: open

Description: A series of computer microtomography experiments are reported which were performed by using a third-generation synchrotron radiation source on volcanic rocks from various active hazardous volcanoes in Italy and other volcanic areas in the world. The applied technique allowed the internal structure of the investigated material to be accurately imaged at the micrometer scale and three-dimensional views of the investigated samples to be produced as well as three-dimensional quantitative measurements of textural features. Thegeometryof thevesicle (gas-filledvoid) network in volcanic products of both basaltic and trachytic compositions were particularly focused on, as vesicle textures are directly linked to the dynamics of volcano degassing. This investigation provided novel insights into modes of gas exsolution, transport and loss in magmas that were not recognized in previous studies using solely conventional two- dimensional imaging techniques. The results of this study are important to understanding the behaviour of volcanoes and can be combined with other geosciences disciplines to forecast their future activity.

Description: In press

Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce

Description: JCR Journal

Description: reserved

Description: One of the main objectives of the project “Development and application of remote sensing methods for the monitoring of active Italian volcanoes” is directed to an operational use of differential interferometry as a tool for volcano monitoring. A first step to achieve this goal is to test commercial software in order to evaluate the most suitable for the project purposes. For testing software, SAR images collected by ERS2 from May 98 to August 98, before and after the strong eruptive event occurred on 22 July 98 at Voragine crater of Etna, have been selected. The explosive event was classified sub-plinian producing a 12 km high eruptive column and lapilli fell on land as far as 70 km south-eastward along the dispersal axis. Pre, post and across event image pairs have been processed. In particular the pair 13 May 98-22 July 98, 22 July 98-26 August 98, 13 May 98-26 August 98 are used for testing respectively pre, post and across event. In first analysis, the fringes in the differential products show a positive elevation trend in the summit area of the volcano. In particular, an increased of about 1,5 fringes in the period pre-event, and a decrement of 1 fringe in the period post-event is observed. This result is agreement whit field of deformation expected in such kind of event, confirming that the interferometric processing tool used id suitable for the purpose of the project.

Description: Published

Description: 15-20

Description: open

Description: The inversion problem dealt with is the identification of the parameters of a magma-filled dike which causes observable changes in ground deformation data. It is supposed that ground deformation data are measured by using the SAR (Synthetic Aperture Radar) Interferometry technique. The inversion approach, which is carried out by a systematic search technique based on the Simulated Annealing (SA) optimization algorithm, guarantees a high degree of accuracy. The results given in the paper are supported by experiments carried out using an interactive software tool developed ad hoc, which allows both direct and inverse modeling of SAR interferometric data related to the opening of a crack at the beginning and throughout a volcanic activity episode.

Description: Published

Description: 30-35

Description: open

Description: Within the framework of the European MVRRS project (Mitigation of Volcanic Risk by Remote Sensing Techniques), in June 1997 an airborne campaign was organised on Mt. Etna to study different characteristics of the volcanic plume emitted by the summit craters in quiescent conditions. Digital images were collected with the Airborne Multispectral Imaging Spectrometer (MIVIS), together with ground-based measurements. MIVIS images were used to calculate the aerosol optical thickness of the volcanic plume. For this purpose, an inversion algorithm was developed based on radiative transfer equations and applied to the upwelling radiance data measured by the sensor. This article presents the preliminary results from this inversion method. One image was selected following the criteria of concomitant atmospheric ground-based measurements necessary to model the atmosphere, plume centrality in the scene to analyse the largest plume area and cloudless conditions. The selected image was calibrated in radiance and geometrically corrected. The 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) radiative transfer model was used to invert the radiative transfer equation and derive the aerosol optical thickness. The inversion procedure takes into account both the spectral albedo of the surface under the plume and the topographic effects on the refl ected radiance, due to the surface orientation and elevation. The result of the inversion procedure is the spatial distribution of the plume optical depth. An average value of 0.1 in the wavelength range 454-474 nm was found for the selected measurement day.

Description: Published

Description: JCR Journal

Description: open

Description: We present an empirical model of sulphur solubility that allows us to calculate f S2 if P, T, fO2 and the melt composition, including H2O and S, are known. The model is calibrated against three main experimental data bases consisting in both dry and hydrous silicate melts. Its prime goal is to calculate the f S2 of hydrous basalts that currently lack experimental constraints of their sulphur solubility behaviour. Application of the model to Stromboli, Vesuvius, Vulcano and Etna eruptive products shows that the primitive magmas found at these volcanoes record f S2 in the range 0.1-1 bar. In contrast, at all volcanoes the magmatic evolution is marked by dramatic variations in f S2 that spreads over up to 9 orders of magnitude. The f S2 can either increase during differentiation or decrease during decompression to shallow reservoirs, and seems to be related to closed versus open conduit conditions, respectively. The calculated f S2 shows that the Italian magmas are undersaturated in a FeS melt, except during closed conduit conditions, in which case differentiation may eventually reach conditions of sulphide melt saturation. The knowledge of f S2, fO2 and fH2O allows us to calculate the fluid phase composition coexisting with magmas at depth in the C-O-H-S system. Calculated fluids show a wide range in composition, with CO2 mole fractions of up to 0.97. Except at shallow levels, the fluid phase is generally dominated by CO2 and H2O species, the mole fractions of SO2 and H2S rarely exceeding 0.05 each. The comparison between calculated fluid compositions and volcanic gases shows that such an approach should provide constraints on both the depth and mode of degassing, as well as on the amount of free fluid in magma reservoirs. Under the assumption of a single step separation of the gas phase in a closed-system condition, the application to Stromboli and Etna suggests that the main reservoirs feeding the eruptions and persistent volcanic plumes at these volcanoes might contain as much as 5 wt% of a free fluid phase. Consideration of the magma budget needed to balance the amounts of volatiles emitted in the light of these results shows that the amount of nonerupted magma could be overestimated by as much as one order of magnitude.

Description: Published

Description: JCR Journal

Description: open

Description: We have characterized the textures of pumice clasts from Phlegraean Fields to gain insights into the conduit flow-dynamics of alkaline explosive eruptions. Vesicularities, vesicle number densities, and vesicle sizes and shapes were measured to obtain the bulk and groundmass properties of the juvenile fraction of Campanian Ignimbrite (CI) and Agnano Monte Spina (AMS) eruptions. The results report the coexistence of three end-member pumice types in the deposits of both eruptions, 1) microvesicular, 2) tube and 3) expanded, which differ according to clast morphology and the macro- to microscopic vesicle texture. Vesicularities (0.85-0.94 for CI, 0.51-0.91 for AMS) and vesicle number densities (2-4×105 cm-2 in CI, 3×105-106 cm-2 in AMS) span quite a wide range in all the three pumice types. Overall, tube pumices exhibit the highest bulk (0.89) and groundmass (CI 0.85, AMS 0.82) average vesicle volume fractions but the lowest average vesicle number densities (CI 2×105, AMS 4×105 cm-2). Comparison with textures of calc-alkaline pumices has revealed many similarities and points to a common origin and distribution of the products from both magma compositions within the volcanic conduit. In addition, the results of the textural analysis were interpreted in the light of the conduit flow modeling of Phlegraean Fields eruptions. The comparison of textural observations with results from simulations of conduit magma ascent has exhibited a good agreement between measured and numerically calculated vesicularities for both compositions, helping to constrain the overall dynamics of alkaline versus calc-alkaline eruptions.

Description: Published

Description: JCR Journal

Description: open

Description: An overview of novel laser techniques suitable for volcanic monitoring, based on different kinds of infrared laser sources, is presented. Their main advantages and drawbacks are discussed focusing on the achievable sensitivity and precision levels in analysis of gaseous species. Some of the most recent experimental results obtained in laboratory development as well as in field tests of home-built laser spectrometers are reported. New perspectives in optical devices aimed at geochemical and geophysical applications are also considered.

Description: Published

Description: JCR Journal

Description: open

Description: On 17th and 18th July 2001, several fractures opened on Mt. Etna southern flank generating different lava flows spreading both in Valle del Bove and towards Nicolosi. On 29th July the image spectrometer MIVIS was flown over Mt. Etna to acquire high-resolution images of the eruption. The MIVIS airborne campaign was planned simultaneously with TERRA, EO-1 and Landsat 7 satellite acquisitions, in order to compare hyperspectral and multispectral data referred to active lavas. This work focuses on the thermal mapping of lava flows, taking advantage of MIVIS sensor high technical performances. The MIVIS high spatial resolution allows a detailed analysis of the lava flow topographic distribution. Its 12 bit dynamic range consents an estimate of the temperature even for the «hottest» pixels. The main target of this work is the evaluation of the energy flux by means of remote-sensing techniques. Surface temperature analysis was performed on distinct lava flows using the dualband technique. These quantities were compared with the integrated temperatures retrieved using the MIVIS thermal infrared bands. The influence of topography was also considered in the flux calculation using a Digital Elevation Model (DEM) of Mt. Etna.

Description: Published

Description: JCR Journal

Description: open

Description: An analytical approach to estimate the relative contribution of the fluid pressure and tectonic stress in hydrothermal/ volcanic areas is proposed assuming a Coulomb criterion of failure. The analytical procedure requires the coefficient of internal friction, cohesion, rock density, and thickness of overburden to be known from geological data. In addition, the orientation of the principal stress axes and the stress ratio must be determined from the inversion of fault-slip or seismic data (focal mechanisms). At first, the stress magnitude is calculated assuming that faulting occurs in 'dry' conditions (fluid pressure=0). In a second step, the fluid pressure is introduced performing a grid search over the orientation of 1) fault planes that slip by shear failure or 2) cracks that open under different values of fluid pressure and calculating the consistency with the observed fault planes (i.e. strike and dip of faults, cracks, nodal planes from focal mechanisms). The analytical method is applied using fault-slip data from the Solfatara volcano (Campi Flegrei, Italy) and seismic data (focal mechanisms) from the Vesuvius volcano (Italy). In these areas, the fluid pressure required to activate faults (shear fractures) and cracks (open fractures) is calculated. At Solfatara, the ratio between the fluid pressure and the vertical stress ?is very low for faults ( ?=0.16) and relatively high for cracks ( ?=0.5). At Vesuvius, ?=0.6. Limits and uncertainties of the method are also discussed.

Description: Published

Description: JCR Journal

Description: open

Description: A 2D finite elements study was carried out to analyse the effects caused by dike intrusion inside a heterogeneous medium and with a realistic topography of Mt. Etna volcano. Firstly, the method (dimension domain, elements type) was calibrated using plane strain models in elastic half-spaces; the results were compared with those obtained from analytical dislocation models. Then the effects caused both by the topographic variations and the presence of multi-layered medium on the surface, were studied. In particular, an application was then considered to Mt. Etna by taking into account the real topography and the stratification deduced from seismic tomography. In these conditions, the effects expected by the dike, employed to model the 2001 eruption under simple elastic half-space medium conditions, were computed, showing that topography is extremely important, at least in the near field.

Description: Published

Description: JCR Journal

Description: open

Description: Vesuvius, dominating the densely-populated Neapolitan area, is one of the most dangerous volcanoes in the World. Its destructive power derives from energetic subplinian and plinian eruptions, such as the one which occurred in 79 A.D. Generally such large-scale events follow a long period of quiescence; a behaviour interpreted as the gradual build-up of magma volumes between periods of major activity. After the 1631 subplinian eruption until the last 1944 A.D. eruption, it experienced an almost continuous and less energetic explosive/effusive activity. The erupted magmas are characterized by undersaturated potassic to ultrapotassic nature, and compositional and Sr-isotopic variability. Furthermore geobarometric studies indicate two different crystallization depths located at 4 and 〉11 km, respectively. According to most of the recent literature, the eruptions were triggered by the injection in a shallower magma chamber, of isotopically distinct magma batches derived from heterogeneous mantle source(s) and/or contamination processes occurred within the deep reservoir. In our review of petrochemical data, we consider the period between the 3550 years BP plinian eruption and the 472 A.D. sub-plinian eruption, which includes 79 A.D. event, and the most recent period of activity which started in 1631 A.D. and lasted up to the 1944 A.D. eruption, characterized by a near continuous effusive/explosive activity. For both periods we identify a correlation between Sr-isotopical features of magmas and their crystallization depth. In particular, we show that pyroxenes have Sr-isotopic ratios lower than 0.7074 and an equilibrium crystallization depth of 22-11 km. Moreover feldspars have higher 87Sr/86Sr values (0.7075-7) and an equilibrium crystallization depth of about 4 km. Therefore the most radiogenic magmas did not derive from a deeper reservoir but their higher Sr-isotopic ratios have been acquired at a shallower depth likely by crustal contamination during magma evolution. In contrast, the lower Sr-isotope compositions characterise the less contaminated magmas coming from deeper crustal levels. On the basis of this evidence, the temporal Sr-isotopical variation of magma which erupted in the 1631-1944 A.D. period probably derives from the progressive withdrawal of the shallow magma chamber, which was completely empty before the 1805-1944 A.D. period of volcanism. Therefore the effusive and explosive events of the most recent 1805-1944 A.D. period were fed directly by the deep reservoir located at a depth exceding 11 km.

Description: Published

Description: JCR Journal

Description: open

Description: Newly acquired high-resolution, low-altitude aeromagnetic data over Vulcano Island and Southwestern Lipari in the Southern Tyrrhenian Sea resolve the major volcanic features in the area associated with the past and present activity. The magnetic character changes in amplitude and frequency from south-east to north-west. The Primordial Vulcano, the Lentia Complex, the Piano Caldera units, the Fossa Caldera deposits, and the currently active La Fossa cone and Vulcanello represent the main volcanic phases on Vulcano Island. They show a distinct magnetic anomaly pattern, whereas prior to this survey, no magnetic signatures of these features were found.

Description: Published

Description: JCR Journal

Description: open