ALBERT

Description: In recent years, new approaches for developing earthquake rupture forecasts (ERFs) have been proposed to be used as an input for probabilistic seismic hazard assessment (PSHA). Zone- based approaches with seismicity rates derived from earthquake catalogs are commonly used in many countries as the standard for national seismic hazard models. In Italy, a single zone- based ERF is currently the basis for the official seismic hazard model. In this contribution, we present eleven new ERFs, including five zone-based, two smoothed seismicity-based, two fault- based, and two geodetic-based, used for a new PSH model in Italy. The ERFs were tested against observed seismicity and were subject to an elicitation procedure by a panel of PSHA experts to verify the scientific robustness and consistency of the forecasts with respect to the observations. Tests and elicitation were finalized to weight the ERFs. The results show a good response to the new inputs to observed seismicity in the last few centuries. The entire approach was a first attempt to build a community-based set of ERFs for an Italian PSHA model. The project involved a large number of seismic hazard practitioners, with their knowledge and experience, and the development of different models to capture and explore a large range of epistemic uncertainties in building ERFs, and represents an important step forward for the new national seismic hazard model.

Description: Published

Description: SE220

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

Description: JCR Journal

Description: Of all the socio-economic changes caused by the Covid-19 pandemic, the disruption to workforce organizations will probably leave the largest indelible mark. The way work will be organized in the future will be closely linked to the experience of work-ing under the same institution’s response to the pandemic. This paper aims to fill the gap in knowledge about smart working (SW) in public organizations, with a focus on the experience of the employees of two Italian research organizations, CNR and INGV. Analysing primary data, it explored and assessed how SW had been experi-enced following the implementation of governmental measures aimed at limiting the spread of COVID-19

Description: Published

Description: 815–833

Description: 2TM. Divulgazione Scientifica

Description: JCR Journal

Description: Data visualization, and to a lesser extent data sonification, are classic tools to the scientific community. However, these two approaches are very rarely combined, although they are highly complementary: our visual system is good at recognizing spatial patterns, whereas our auditory system is better tuned for temporal patterns. In this article, data representation methods are proposed that combine visualization, sonification, and spatial audio techniques, in order to optimize the user’s perception of spatial and temporal patterns in a single display, to increase the feeling of immersion, and to take advantage of multimodal integration mechanisms. Three seismic data sets are used to illustrate the methods, covering different physical phenomena, time scales, spatial distributions, and spatio-temporal dynamics. The methods are adapted to the specificities of each data set, and to the amount of information that the designer wants to display. This leads to further developments, namely the use of audification with two time scales, the switch from pure audification to time-modulated noise, and the switch from pure audification to sonic icons. First user feedback from live demonstrations indicates that the methods presented in this article seem to enhance the perception of spatio-temporal patterns, which is a key parameter to the understanding of seismically active systems, and a step towards apprehending the processes that drive this activity.

Description: Published

Description: 125–142

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

Description: JCR Journal

Description: Il presente lavoro raccoglie alcune esperienze di Progetti di Alternanza Scuola Lavoro (d’ora in poi ASL) realizzati dall’INGV negli anni scolastici dal 2015 al 2019 e dedicati al rischio sismico, alle scienze polari ed agli strumenti per la divulgazione scientifica. Le esperienze descrivono il lavoro realizzato da un gruppo di ricercatori INGV con competenze in diversi ambiti disciplinari (sismologia, geologia, vulcanologia fisica dell’atmosfera, psicologia) e in alcuni casi le attività sono state svolte in collaborazione con ricercatori di altri enti. Il gruppo di lavoro è composto da ricercatori che da molti anni dedicano parte del loro tempo-lavoro alle attività di divulgazione scientifica, ai progetti educativi, alla didattica della scienza. In una parola a quella che oggi rappresenta, per gli enti di ricerca, la “Terza missione”, ovvero l’insieme di tutte le attività finalizzate a creare una connessione bidirezionale tra il mondo della ricerca e la società. Ciò che ha caratterizzato l’approccio dei ricercatori INGV ai progetti ASL, sia nella fase di progettazione che di realizzazione, è la finalità di consentire agli studenti di vivere un’esperienza reale ed immersiva in un contesto di lavoro. E quindi l’opportunità di sperimentare capacità e abilità che caratterizzano il contesto organizzativo (diritti, doveri, responsabilità, impegni, regole), diversamente dal mondo della scuola. Il secondo aspetto al quale ci si è riferiti nella realizzazione dei progetti è quello di consentire agli studenti di esplorare, in particolare il contesto delle attività lavorative connesse al mondo della ricerca. Da questo punto di vista gli studenti hanno potuto acquisire conoscenze in ambiti tematici specifici, hanno avuto modo di sperimentare metodi e tecniche proprie del mondo della ricerca e di acquisire capacità e abilità trasversali come il lavoro in gruppo. Il contributo è organizzato in tre capitoli in relazione ai temi affrontati nei progetti. Nel primo sono riportate le schede dei tre progetti dedicate al tema Terremoto; nel secondo vengono descritti i due progetti dedicati alla Divulgazione Scientifica e nel terzo un progetto sulle Scienze Polari. Per rendere maggiormente fruibile la lettura, ogni progetto viene descritto attraverso una scheda sintetica che evidenza le caratteristiche principali: titolo, referenti INGV, studenti partecipanti, periodo, descrizione delle attività, obiettivi e considerazioni sull’esperienza. Nel capitolo conclusivo viene proposto un bilancio delle esperienze realizzate, evidenziando punti di forza e aree di miglioramento dei progetti, con la finalità di condividere suggerimenti ed idee per tracciare percorsi formativi maggiormente efficaci nel futuro.

Description: Published

Description: 119-131

Description: 2TM. Divulgazione Scientifica

Description: N/A or not JCR

Description: We present the commented transcription of three rare articles published in 19091910 by Father Atto Maccioni o.f.m. This friar is one of the least known among the many ecclesiastics who cultivated seismology from the 18th century onwards. Maccioni, from 1908 to 1926, managed a seismic observatory at the Sienese convent of the Osservanza. He devised an “Avvisatore”: a device equipped with a modified coherer with respect to those adopted in radiotelegraphic communications, aimed to detect natural radio signals associated with earthquakes. From the few available results it seems that the scholar obtained positive feedback, but the most interesting aspect of the story is that until now it was generally believed that this kind of research began only quite recently [Warwick, 1982]. On the contrary Maccioni may have been the first ever to study a possible electromagnetic precursor, more than a century ago.

Description: Presentiamo la trascrizione commentata di tre rari articoli pubblicati nel 19091910 da padre Atto Maccioni o.f.m., uno dei meno noti tra i tanti ecclesiastici che si sono occupati di sismologia dal XVIII secolo in poi. Maccioni, che dal 1908 al 1926 gestì un osservatorio sismico presso il convento senese dell’Osservanza, aveva ideato l’Avvisatore, un dispositivo munito di un coherer diverso da quelli radiotelegrafici e destinato a rilevare segnali radio naturali associati ai terremoti. Dai pochi risultati disponibili sembra che lo studioso abbia avuto dei riscontri positivi ma l’aspetto più interessante della vicenda è che finora si era creduto che ricerche di questo tipo fossero iniziate solo molto di recente [Warwick, 1982]. Invece Maccioni potrebbe essere stato il primo al mondo a studiare, più di un secolo fa, un ipotetico precursore elettromagnetico.

Description: Published

Description: 1-32

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

Description: 2TM. Divulgazione Scientifica

Description: N/A or not JCR

Description: Historical seismic catalogs report that the Gargano Promontory (southern Italy) was affected in the past by earthquakes with medium to high estimated magnitude. From the instrumental seismicity, it can be identified that the most energetic Apulian sequence occurred in 1995 with a main shock of MW = 5.2 followed by about 200 aftershocks with a maximum magnitude of 3.7. The most energetic earthquakes of the past are attributed to right-lateral strike-slip faults, while there is evidence that the present-day seismicity occur on thrust or thrust-strike faults. In this article, we show a detailed study on focal mechanisms and stress field obtained by micro-seismicity recorded from April 2013 until the present time in the Gargano Promontory and surrounding regions. Seismic waveforms are collected from the OTRIONS Seismic Network (OSN), from the Italian National Seismic Network (RSN), and integrated with data from the Italian National Accelerometric Network (RAN) in order to provide a robust dataset of earthquake localizations and focal mechanisms. The effect of uncertainties of the velocity model on fault plane solutions (FPS) has been also evaluated indicating the robustness of the results. The computed stress field indicates a deep compressive faulting with maximum horizontal compressive stress, SHmax, trending NW-SE. The seismicity pattern analysis indicates that the whole crust is seismically involved up to a depth of 40 km and indicates the presence of a low-angle seismogenic surface trending SW-NE and dipping SE-NW, similar to the Gargano–Dubrovnik lineament. Shallower events, along the eastern sector of the Mattinata Fault (MF), are W-E dextral strike-slip fault. Therefore, we hypothesized that the seismicity is locally facilitated by preexisting multidirectional fractures, confirmed by the heterogeneity of focal mechanisms, and explained by the different reactivation processes in opposite directions over the time, involving the Mattinata shear zone.

Description: Published

Description: 589332

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Cold-water corals (CWC) can be found throughout a wide range of latitudes (79°N–78°S). Since they lack the photosymbiosis known for most of their tropical counterparts, they may thrive below the euphotic zone. Consequently, their growth predominantly depends on the prevalent environmental conditions, such as general food availability, seawater chemistry, currents, and temperature. Most CWC communities live in regions that will face CaCO3 undersaturation by the end of the century and are thus predicted to be threatened by ocean acidification (OA). This scenario is especially true for species inhabiting the Chilean fjord system, where present-day carbonate water chemistry already reaches values predicted for the end of the century. To understand the effect of the prevailing environmental conditions on the biomineralization of the CWC Tethocyathus endesa, a solitary scleractinian widely distributed in the Chilean Comau Fjord, a 12-month in situ experiment was conducted. The in situ skeletal growth of the test corals was assessed at two sites using the buoyant weight method. Sites were chosen to cover the naturally present carbonate chemistry gradient, with pH levels ranging between 7.90 ± 0.01 (mean ± SD) and 7.70 ± 0.02, and an aragonite saturation (Ωarag) between 1.47 ± 0.03 and 0.98 ± 0.05. The findings of this study provide one of the first in situ growth assessments of a solitary CWC species, with a skeletal mass increase of 46 ± 28 mg per year and individual, at a rate of 0.03 ± 0.02% day. They also indicate that, although the local seawater chemistry can be assumed to be unfavorable for calcification, growth rates of T. endesa are comparable to other cold-water scleractinians in less corrosive waters (e.g., Lophelia pertusa in the Mediterranean Sea).

Description: Short-term earthquake clustering properties in the Eastern Aegean Sea (Greece) area investigated through the application of an epidemic type stochastic model (Epidemic Type Earthquake Sequence; ETES). The computations are performed in an earthquake catalog covering the period 2008 to 2020 and including 2332 events with a completeness threshold of Mc = 3.1 and separated into two subcatalogs. The first subcatalog is employed for the learning period, which is between 2008/01/01 and 2016/12/31 (N = 1197 earthquakes), and used for the model’s parameters estimation. The second subcatalog from 2017/01/01 to 2020/11/10 (1135 earthquakes), in which the sequences of 2017 Mw = 6.4 Lesvos, 2017 Mw = 6.6 Kos and 2020 Mw = 7.0 Samos main shocks are included, and used for a retrospective forecast testing based on the constructed model. The estimated model parameters imply a swarm like behavior, indicating the ability of earthquakes of small to moderate magnitude above Mc to produce their own offsprings, along with the stronger earthquakes. The retrospective evaluation of the model is examined in the three aftershock sequences, where lack of foreshocks resulted in low predictability of the mainshocks, with estimated daily probabilities around 10– 5. Immediately after the mainshocks occurrence the model adjusts with notable resemblance between the expected and observed aftershock rates, particularly for earthquakes with M ≥ 3.5.

Description: Published

Description: 1085–1099

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

Description: JCR Journal

Description: In this paper, based on non-negative matrix factorization (NMF), we analyzed the ionosphere magnetic field data of the Swarm Alpha satellite before the 2016 (Mw = 7. 8) Ecuador earthquake (April 16, 0.35°N, 79.93°W), including the whole data collected under quiet and disturbed geomagnetic conditions. The data from each track were decomposed into basis features and their corresponding weights. We found that the energy and entropy of one of the weight components were more concentrated inside the earthquake-sensitive area, which meant that this weight component was more likely to reflect the activity inside the earthquake-sensitive area. We focused on this weight component and used five times the root mean square (RMS) to extract the anomalies. We found that for this weight component, the cumulative number of tracks, which had anomalies inside the earthquake-sensitive area, showed accelerated growth before the Ecuador earthquake and recovered to linear growth after the earthquake. To verify that the accelerated cumulative anomaly was possibly associated with the earthquake, we excluded the influence of the geomagnetic activity and plasma bubble. Through the random earthquake study and low-seismicity period study, we found that the accelerated cumulative anomaly was not obtained by chance. Moreover, we observed that the cumulative Benioff strain S, which reflected the lithosphere activity, had acceleration behavior similar to the accelerated cumulative anomaly of the ionosphere magnetic field, which suggested that the anomaly that we obtained was possibly associated with the Ecuador earthquake and could be described by one of the Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) models.

Description: This research was supported by the National Natural Science Foundation of China under Grant No. 41974084 and the International Cooperation Project of Department of Science and Technology of Jilin Province No. 20200801036GH.

Description: Published

Description: 621976

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

Description: JCR Journal

Description: The best chance to achieve a future disaster-resilient society is through risk education in School: it has a great potential to strengthen capacity of communities to mitigate risks. The KnowRISK (Know your city, Reduce seISmic risK through non-structural elements) project took this opportunity and implemented a risk communication campaign for schools in Portugal, Italy, and Iceland. The idea was that suitably changes in people’s knowledge and attitude can trigger best practices. Crucial to reach such target is the raise of awareness on meaningful issues. The main challenge of the campaign was how to effectively address the mitigation of the vulnerability to earthquakes of non-structural elements, which is an issue considered to be of low priority even in the building regulations of many countries around the world. The campaign stood on a communication strategy that was systematized within a protocol, for 13- 15 years old students, that specifies goals, contents, learning strategy, support material, and relies on face-to-face intervention of scientists in the classroom. This protocol had training sessions bounded by assessment sessions, ex-ante and ex-post, that allowed to validate its efficacy. The training made large use of flipped learning and Episode of Situated Learning (EAS) strategy to raise student’s motivation and increase achievements. To ensure its replicability, the protocol was tested in zones matching a wide range of seismic hazard in Italy. The assessment showed the protocol be effective and ready for a wide dissemination.

Description: Published

Description: SE325

Description: 2TM. Divulgazione Scientifica

Description: JCR Journal

Description: This work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Description: Published

Description: 3287–3315

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

Description: JCR Journal

Description: Probabilistic earthquake locations provide confidence intervals for the hypocentre solutions such as errors encountered in the position, the origin time, and in magnitude. If the relationship of the parameters relative to the local arrangement of the seismic network is considered, such as the node distance, the number of stations, the seismic gap, and the quality of phase readings), the uncertainties can then provide insights on the location capability of the network. In this paper, we collect the earthquake data recorded from the Italian Seismic Network for a time span of 5 years. The data pertain to three different catalogues according to the progressive refinement phases of the location procedure: automatic location, revised location, and published location. By means of spatial analysis,we assess the distribution of the location-related and network-related estimators across the study area. These estimators are subsequently combined to assess the existence of spatial correlations at a local scale. The results indicate that the Italian network is generally able to provide robust locations at the national scale and for smaller earthquakes, and the elongated shape of Italy (and of its network) does not cause systematic bias in the locations. However, we highlight the existence of subregions in which the performance of the network is weaker. At present, a unique 2D, 3-layer velocity model is used for the earthquake location procedure, and this could represent the main limitation for the improvement of the locations. Therefore, the assessment of locally optimized velocity models is the priority for the homogenization and the improvement of the Italian Seismic Network performance.

Description: Published

Description: 1061–1076

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: JCR Journal

Description: Since the first studies on biogeophysics in the early 2000s our understanding of how biogeochemical processes affect geophysical signatures has significantly improved. This interdisciplinary field now incorporates and integrates environmental and rock magnetism with traditional biological and geochemical methods to interpret geophysical signatures in highly dynamic environments (e.g., biogeochemical hotspots, contamination plumes). Environmental magnetism, in particular, can trace environmental changes by identifying magnetic mineral transformations induced from several biogeochemical processes. This Special Issue includes papers that present applications of environmental and rock magnetism in biogeophysics and discuss their impact on Earth Sciences.

Description: Published

Description: 757171

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: JCR Journal

Description: In aree di vulcanismo attivo e recente, oltre all’emissione di vapore e gas dai crateri centrali, si possono verificare emissioni di gas dal suolo che vengono rilasciati in modo diffuso o in mofete, o ancora che si disciolgono in acquiferi superficiali. Generalmente il gas più abbondante (fino al 99 vol.%) è l’anidride carbonica (CO2), ma in alcuni casi può essere anche il metano (CH4). La CO2 è un gas incolore e inodore che tende ad accumularsi in depressioni o scantinati dove ristagna in assenza di vento. Respirare aria con una concentrazione di anidride carbonica maggiore di 8 vol.% può condurre all’incoscienza o alla morte. Un esempio di quello che potrebbe accadere, anche se si tratta di un caso estremo, è rappresentato dal tragico evento avvenuto presso il lago Nyos in Camerun (un lago ospitato in un cratere vulcanico). Durante la notte del 21 agosto 1986 le acque del lago, sature di CO2, si rovesciarono improvvisamente e per decompressione si liberò una enorme quantità di gas che scese lungo i fianchi del cratere fino a raggiungere la valle sottostante dove vi era un villaggio. La nube di CO2, silenziosa e inodore, colse nel sonno gli abitanti e uccise circa 1700 persone e circa 3000 capi di bestiame [Barberi et al., 1986]. Numerosi incidenti dovuti all’inalazione di gas vulcanici sono avvenuti in varie altre parti del mondo, in particolare in Italia, Giappone, Nuova Zelanda [Hansell and Oppenheimer, 2004; Durand and Wilson, 2005] e nelle Isole Azzorre (Portogallo) [Viveiros et al., 2015]. Anche in Italia, purtroppo sono avvenuti diversi incidenti letali dovuti ad inalazione di CO2; si ricorda ad esempio che alla fine degli anni ’80 due bambini persero la vita nell’isola di Vulcano [Baubron et al., 1990] e ancora nel complesso vulcanico dei Colli Albani due uomini persero la vita, il primo a Cava dei Selci (frazione di Marino) nel 2000 e il secondo a Lavinio nel 2011 [Carapezza et al., 2003; Barberi et al., 2019]. Sempre in provincia di Roma, numerosi casi di intossicazione da CO2, che hanno altresì comportato l’evacuazione temporanea di alcune abitazioni, sono avvenuti per blowout (emissione incontrollata) di gas da pozzi d’acqua [Barberi et al., 2007; Carapezza et al., 2020]. La Campania ospita due dei vulcani quiescenti considerati tra i più pericolosi al mondo proprio per l’alta densità di popolazione che vive nelle zone esposte al pericolo: il Vesuvio e i Campi Flegrei. Anche in queste aree vulcaniche si hanno emissioni di gas endogeni e falde d’acqua ricche in CO2 e in caso di riattivazione del vulcano c’è da aspettarsi anche un forte incremento del rilascio del gas endogeno [Barberi et al., 2005]. Al fine di far conoscere tale problematica alla popolazione, si è ritenuto opportuno di agire sui ragazzi e di farlo in modo stimolante e divertente attraverso un Videogioco che catturi la loro attenzione in modo da portarli a scoprire le soluzioni più adeguate da adottare per individuare/evitare/gestire i pericoli legati a quello che spesso viene definito anche “carburante delle eruzioni”, i gas vulcanici. Le attività che hanno portato alla realizzazione di questo lavoro (e nello specifico del videogioco) sono state svolte nell’ambito del Progetto Europeo RESPIRE – Radon rEal time monitoring System and proactive Indoor Remediation (LIFE16ENV/IT/000553) e con la collaborazione di un Tirocinante del Dipartimento di Ingegneria dell’Informazione ed Elettrica e Matematica Applicata dell’Università degli Studi di Salerno. Il lavoro è stato descritto e sintetizzato in questo Report attraverso varie sezioni. La prima in cui si descrive la problematica dei Gas Vulcanici e della loro pericolosità; l’importanza e i vantaggi derivati dall’utilizzo di un videogioco come strumento di apprendimento; l’obiettivo che il videogioco si prefigge di raggiungere. Una seconda sezione in cui, in prima istanza, si evidenzia l’importanza di sviluppare un videogioco a partire da un Motore Grafico che consente di tralasciare i dettagli hardware e software di basso livello e di concentrarsi maggiormente sull’interattività e sulle regole del gioco, e in seconda istanza si descrivono le caratteristiche principali del motore grafico alla base del gioco (RPG Maker MV).Una terza sezione in cui viene presentato il videogioco sviluppato denominato “GioGas”; nello specifico, la sua trama, l’interfaccia grafica che lo caratterizza e alcuni sui dettagli implementativi. Infine, una sezione in cui vengono descritti gli sviluppi futuri come ad esempio la divulgazione presso le scuole e in occasione di eventi, l’implementazione di una versione multiplayer del gioco al fine di aggiungere ulteriori elementi di stimolo e di coinvolgimento per lo studente.

Description: Published

Description: 6SR VULCANI – Servizi e ricerca per la società

Description: N/A or not JCR

Description: This paper provides a new contribution to the construction of the complex and fragmentary mosaic of the Late Holocene earthquakes history of the İznik segment of the central strand of the North Anatolian Fault (CNAF) in Turkey. The CNAF clearly displays lower dextral slip rates with respect to the northern strand however, surface rupturing and large damaging earthquakes (M 〉 7) occurred in the past, leaving clear signatures in the built and natural environments. The association of these historical events to specific earthquake sources (e.g., Gemlik, İznik, or Geyve fault segments) is still a matter of debate. We excavated two trenches across the İznik fault trace near Mustafali, a village about 10 km WSW of İznik where the morphological fault scarp was visible although modified by agricultural activities. Radiocarbon and TL dating on samples collected from the trenches show that the displaced deposits are very recent and span the past 2 millennia at most. Evidence for four surface faulting events was found in the Mustafali trenches. The integration of these results with historical data and previous paleoseismological data yields an updated Late Holocene history of surface-rupturing earthquakes along the İznik Fault in 1855, 740 (715), 362, and 121 CE. Evidence for the large M7 + historical earthquake dated 1419 CE generally attributed to this fault, was not found at any trench site along the İznik fault nor in the subaqueous record. This unfit between paleoseismological, stratigraphic, and historical data highlights one more time the urge for extensive paleoseismological trenching and offshore campaigns because of the high potential to solve the uncertainties on the seismogenic history (age, earthquake location, extent of the rupture and size) of this portion of NAFZ and especially on the attribution of historical earthquakes to the causative fault.

Description: Published

Description: 115–128

Description: 2T. Deformazione crostale attiva

Description: N/A or not JCR

Description: PGS1 is a new compact portable seismic station, designed at INGV OBS and Earth Lab, that is specifically intended for the deployment of dense arrays of seismographs on-shore. With its low cost, compact design, high data-quality and long battery life, PGS1 is a perfect solution for seismic monitoring networks. PGS1 design is based on a solid polypropylene suitcase, containing a complete data acquisition system, two battery packs and a photovoltaic panel. The new Earth Lab 5s medium-period seismic sensor is included. The whole system meets the IP67 standard requirements both in transport and in acquisition configuration. PGS1 is normally equipped with one battery pack, one more pack can be added inside the suitcase achieving 40 days of battery life. The station is equipped with a photovoltaic panel, useful to extend the deployment length. Inside the suitcase, there are compartments where to store the seismic sensor, the photovoltaic panel and all the cables. Therefore, the station is very easy to transport.

Description: Published

Description: SE105

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: JCR Journal

Description: Tsunamis are unpredictable and infrequent but potentially large impact natural disasters. To prepare, mitigate and prevent losses from tsunamis, probabilistic hazard and risk analysis methods have been developed and have proved useful. However, large gaps and uncertainties still exist and many steps in the assessment methods lack information, theoretical foundation, or commonly accepted methods. Moreover, applied methods have very different levels of maturity, from already advanced probabilistic tsunami hazard analysis for earthquake sources, to less mature probabilistic risk analysis. In this review we give an overview of the current state of probabilistic tsunami hazard and risk analysis. Identifying research gaps, we offer suggestions for future research directions. An extensive literature list allows for branching into diverse aspects of this scientific approach.

Description: Published

Description: 628772

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

Description: JCR Journal

Description: Low field magnetic susceptibility and other rock magnetic analyses are applied to inspect the magnetic nature of solid residuals in snow samples collected in downtown Rome and in two Natural Parks in central Italy. Field emission scanning electron microscope and energy dispersive spectroscopy (FESEM-EDS) analyses are utilized to reveal the nature of Fe-rich particles and discriminate their anthropogenic origin. The results indicate that magnetite (Fe3O4) is the main magnetic carrier in almost all samples and that the variations in concentration are directly associated with local sources of particulate matter (PM) from anthropogenic pollution related to automotive circulation in both environments. Magnetic minerals of other provenance are found as accessories. The snow deposits revealed to be an efficient neutral tool for fine particle collections, also in environments characterized by different concentration and source of pollutants.

Description: Published

Description: GM215

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: JCR Journal

Description: Since the beginning of the XXI Century, our society has witnessed a number of catastrophic earthquakes with devastating consequences (e.g., Sumatra 2004, Haiti 2010, Japan 2010, Nepal 2015, Italy 2009 and 2016). Localizing the active faults and understanding their earthquake history is key to improve modern probabilistic seismic hazard assessment (PSHA) and, thus, to mitigate the consequences of future events. Seismicity models to characterize the earthquake frequency in a region in PSHA studies have been traditionally based on archaeological, historical and instrumental earthquake records. However, the rapid advance of active tectonics and paleoseismological studies has resulted in the development of seismicity models for faults, since they allow characterizing the active faults, reconstructing their 3D geometry at depth, and determining their past earthquake history and seismic potential based on the interpretation of the geological record. Traditionally, active tectonics and paleoseismological research had been mainly conducted to study onshore active faults. However, the occurrence of the offshore Sumatra (2004) and Japan (2010) earthquakes and consequent tsunamis, which caused tens of thousands of casualties and extensive and severe damage and economic losses, have brought into sharp focus the need to better understand the geohazards related to submarine active faults. In the last few years, the availability of offshore geological and geophysical data at various scales (e.g., deep and shallow borehole, wide angle seismic profiles, tomography, 3D and 2D seismic reflection surveys, high resolution bathymetry or seafloor imaging) has allowed for a better definition of offshore fault systems. These studies focused on accurately constraining the kinematic, architecture and linkage of active faults, and, in some cases, identify recent earthquake ruptures or recognize and date individual events. In addition, underwater active tectonics and paleoseismological studies benefit from: (1) low erosional rates that preserve fault morphology and segmentation; (2) continuous sedimentation in time and space that allows for local and/or regional stratigraphic and chronostratigraphic correlations; (3)multiscale seafloor mapping and sub-seafloor seismic imaging; and 4) absence–or lowest amount–of human modification. This Research Topic includes fourteen published articles focused in the study of underwater active tectonic regions or active fault systems around the world

Description: Published

Description: 809205

Description: 2T. Deformazione crostale attiva

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

Description: JCR Journal

Description: Deciphering the triggering mechanisms of violent explosive activity is of broad interest for understanding the dynamics of basaltic open-vent volcanic systems. For nearly 1300 years Stromboli has been renowned not only for its continuous degassing activity and mild explosions at the summit craters, but also for short-lived, violent explosive events of variable scale, known as major explosions and paroxysms. Here, we focus on the 1456 and 1930 paroxysms and on the most recent events, in July and August 2019 at Stromboli. We show that shallow phenomena such as flank collapse, lava outpouring through fractures opening, or partial emptying of the shallow conduit, only speed up volatile-rich magma ascent by increasing the decompression rate, whereas pressurization of the crustal system and the deep refilling by magma and its CO2-rich gas phase play a major role in triggering paroxysms. Moreover, we present new data on the geochemistry of the 2019 bulk pumice, along with a compilation of data from the literature, chemical profiles in olivine crystals, and the physical parameters of explosive eruptions of wide ranging magnitude and intensity. For small and large paroxysms, timescales were derived from Fe–Mg diffusion profiles in olivine. In both types of explosion, the last phases of crystallization-diffusion indicate rapid magma ascent rates of two to ten days prior to eruption. Trace element concentrations (Nb, La and Ba) and ratios (Rb/Th) indicate that the 2019 pumice samples plot in the domain of magma batches erupted within the last 20 years at Stromboli. As a whole, there is no correlation between magma geochemistry and magnitude or intensity of explosive eruptions, which span a range of ∼3 orders of magnitude (from major explosions to large paroxysms) based on estimates of erupted tephra volumes. In contrast, olivine compositions are a good proxy for erupted tephra volumes and magma flux. The correlation among physical and chemical parameters, which is valid for the overall spectrum of eruptions, implies that the magmatic source ultimately controls eruptive dynamics.

Description: Published

Description: 593339

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: The 1971 eruption represents a benchmark in the recent history of Etna volcano. From a volcanological point of view, this eruption was characterised by complex intrusive dynamics associated with significant ground deformation that induced the activation of the Moscarello seismogenic fault and the formation of a new summit crater: the Southeast Crater. At the same time, the 1971 event marks an important change in the eruptive style and composition of the magma towards products richer in K. It is no coincidence that, over the next fifty years, there would be an increase in the frequency of summit and flank eruptions and associated output rate. From an historical viewpoint, the eruptive event of 1971 was the first important flank eruption studied by the International Institute of Volcanology: the analysis of the scientific articles on this activity reveals a greater multidisciplinary content in the descriptions and explanations of volcanic activity. Particularly important were the collaborations of British and French research groups that, together with their Italian colleagues, succeeded in giving a complete picture of the eruption and describing the state of knowledge on the Sicilian volcano. The multidisciplinary methodology used to study this eruption is still valid today.

Description: Published

Description: VO543

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: Here we introduce the updated, interactive and open-access database for African volcanic lakes, country by country. The previous database VOLADA (VOlcanic LAke DAta Base, Rouwet et al., 2014) reported 96 volcanic lakes for Africa. This number is now revised and established at 220, converting VOLADA_Africa 2.0 in the most comprehensive resource for African volcanic lakes: 81 in Uganda, 37 in Kenya, 33 in Cameroon, 28 in Madagascar, 19 in Ethiopia, 6 in Tanzania, 2 in Rwanda, 2 in Sudan, 2 in D.R. Congo, 1 in Libya, and 9 on the minor islands around Africa. We present the current state-of-the-art of arguably all the African volcanic lakes that the global experts and regional research teams are aware of, and provide hints for future research directions, with a special focus on the volcanic hazard assessment. All lakes in the updated database are classified for their genetic origin and their physical and chemical characteristics, and level of study. The predominant rift-related volcanism in Africa favors basaltic eruptive products, leading to volcanoes with highly permeable edifices (e.g. scoria), and hence less-developed hydrothermal systems. Basal aquifers accumulate under large volcanoes and in rift depressions providing a potential scenario for phreatomagmatic volcanism. This hypothesis, based on a morphometric analysis and volcanological research from literature, conveys the predominance of maar lakes in large monogenetic fields in Africa (e.g. Uganda, Cameroon, Ethiopia), and the absence of high-activity crater lakes, generally found at arc-volcanoes. Considering the large number of maar lakes in Africa (172), within similar geotectonic settings and meteoric conditions as in Cameroon, it is somewhat surprising that “only” from Lake Monoun and Lake Nyos fatal CO2 bursts have been recorded. Explaining why other maars did not erupt in such fashion is a question that can only be answered by enhancing insights into physical limnology and fluid geochemistry of the so far poorly studied lakes. From a hazard perspective, there is an urgent need to tackle this task as a community.

Description: Published

Description: 717798

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: This study analyses the relationship between the pre- and protohistoric sites on the slopes of Etna and the volcanic products, as well as the diverse settlement strategies in the different periods of prehistory. New C14 dating from significant excavations, in addition to those known from other Etnean sites, were performed with the aim of validating the chronology of the sequence of the different phases. A substantial concordance of the archaeological data with the volcanological ones has been found. It has been observed that a consistent human presence on Etna appears from the Middle Neolithic (5500 BC), after the sequence of eruptive events that marked the end of the Ellittico volcano (13550 - 13050 BC) and the formation of the Valle del Bove, and the subsequent debris and alluvial events on the eastern flanks of the volcano (7250 - 3350 BC). Human presence intensifies between the Late-Final Copper Age and the Early Bronze Age (2800 - 1450 BC), due to improvement in subsistence techniques and to the large presence of soils on lava flows suitable for sheep farming. The most recent phases of the Bronze Age are poorly represented, probably because of the concentration of the population in larger agglomerations (Montevergine and S. Paolillo at Catania, the Historical Hill at Paternò). The explosive eruptions taking place in this period seem to have had less impact on the settlement choices and have not affected the development of the sites over time.

Description: Published

Description: VO542

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: We present a benchmark study aimed at identifying the most effective modeling approach for tsunami generation, propagation, and hazard in an active volcanic context, such as the island of Stromboli (Italy). We take as a reference scenario the 2002 landslide-generated tsunami event at Stromboli simulated to assess the relative sensitivity of numerical predictions to the landslide and the wave models, with our analysis limited to the submarine landslide case. Two numerical codes, at different levels of approximation, have been compared in this study: the NHWAVE three-dimensional non-hydrostaticmodel in sigma-coordinates and theMultilayer-HySEA model. In particular, different instances of Multilayer-HySEA with one or more vertical discretization layers, in hydrostatic and non-hydrostatic formulation and with different landslide models have been tested. Model results have been compared for the maximum runup along the shores of Stromboli village, and the waveform sampled at four proximal sites (two of them corresponding to the locations of the monitoring gauges, offshore the Sciara del Fuoco). Both rigid and deformable (granular) submarine landslide models, with volumes ranging from 7 to 25 million of cubic meters, have been used to trigger the water waves, with different physical descriptions of the mass movement. Close to the source, the maximum surface elevation and the resulting runup at the Stromboli village shores obtainedwith hydrostatic and non-hydrostaticmodels are similar. However, hydrostatic models overestimate (with respect to non-hydrostatic ones) the amplitude of the initial positive wave crest, whose height increases with the distance. Moreover, as expected, results indicate significant differences between the waveforms produced by the different models at proximal locations. The accuratemodeling of near-field waveforms is particularly critical at Stromboli in the perspective of using the installed proximal sea-level gauges, together with numerical simulations, to characterize tsunami source in an early-warning system. We show that the use of non-hydrostatic models, coupled with a multilayer approach, allows a better description of the waveforms. However, the source description remains the most sensitive (and uncertain) aspect of the modeling. We finally show that non-hydrostatic models, such as Multilayer-HySEA, solved on accelerated GPU architectures, exhibit the optimal trade-off between accuracy and computational requirements, at least for the envisaged problem size and for what concerns the proximal wave field of tsunamis generated by volcano landslides. Their application and future developments are opening new avenues to tsunami early warning at Stromboli.

Description: Published

Description: 628652

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: This special issue of Annals of Geophysics entitled: “When Volcanologists Meet Archaeologists and Other Disciplines: Relationships Between Eruptions and Human Communities” originates from a session (S13) of the Rittmann International Conference which took place in Catania on February 13th 2020, having as its main theme the history of volcanology and the impact of volcanic activity on humans. The twelve articles collected in this special issue reflect the aims and contents of the reports presented by some participants at this session of the Rittmann conference

Description: Published

Description: 6SR VULCANI – Servizi e ricerca per la società

Description: JCR Journal

Description: Published

Description: 6TM. Poli Museali

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 8 September 1905 Calabria earthquake is the seismic event for which the Italian Seismic Catalogue shows the highest instrumental magnitude of the whole dataset. However, the reported MS = 7.47 was calculated over only two stations, and leaves room for a revision. In this work I provide a new estimate of the surface-wave magnitude of the earthquake calculated over sixteen individual values of magnitude from seven different stations. The new estimate is MS = 7.10 ± 0.21, a value that is consistently lined up with other estimates provided by means of macroseismic or geological evidence. The novel estimate is stable despite alternative epicentral locations and different depths proposed for this event by several investigators. The net variation of almost half a unit magnitude implies a resizing of the seismogenic source of the event in the frame of the seismotectonics of the region, and highlights the strong need for a systematic revision of the instrumental magnitude estimates for several ‘historical’ earthquakes that occurred at the dawning of the instrumental seismology.

Description: Published

Description: SE658

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: In order to be able to forecast the weather and estimate future climate changes in the ocean, it is crucial to understand the past and the mechanisms responsible for the ocean variability. This is particularly true in a complex area such as the Mediterranean Sea with diverse dynamics like deep convection and overturning circulation. To this end, effective tools are ocean reanalyses or reconstructions of the past ocean state. Here we present a new physical reanalysis of the Mediterranean Sea at high resolution, developed in the Copernicus Marine Environment Monitoring Service (CMEMS) framework. The hydrodynamic model is based on the Nucleus for European Modelling of the Ocean (NEMO) combined with a variational data assimilation scheme (OceanVar). The model has a horizontal resolution of 1/24° and 141 unevenly distributed vertical z* levels. It provides daily and monthly temperature, salinity, current, sea level and mixed layer depth as well as hourly fields for surface velocities and sea level. ECMWF ERA-5 atmospheric fields force the model and daily boundary conditions in the Atlantic are taken from a global reanalysis. The reanalysis covers the 33 years from 1987 to 2019. Initialized from SeaDataNet climatology in January 1985, it reaches a nominal state after a 2-years spin-up. In-situ data from CTD, ARGO floats and XBT are assimilated into the model in combination with satellite altimetry observations. This reanalysis has been validated and assessed through comparison to in-situ and satellite observations as well as literature climatologies. The results show an overall improvement of the comparison with observations and a better representation of the main dynamics of the region compared to a previous, lower resolution (1/16°), reanalysis. Temperature and salinity RMSD are decreased by respectively 14 and 18%. The salinity biases at depth of the previous version are corrected. Climate signals show continuous increase of the temperature and salinity, confirming estimates from observations and other reanalysis. The new reanalysis will allow the study of physical processes at multi-scales, from the large scale to the transient small mesoscale structures and the selection of climate indicators for the basin.

Description: Published

Description: 702285

Description: 4A. Oceanografia e clima

Description: JCR Journal

Description: Seismic activity in volcanic settings could be the signature of processes that include magma dynamics, hydrothermal activity and geodynamics. The main goal of this study is to analyze the seismicity of Lipari Island (Southern Tyrrhenian Sea) to characterize the dynamic processes such as the interaction between pre-existing structures and hydrothermal processes affecting the Aeolian Islands. We deployed a dense seismic array of 48 autonomous 3-component nodes. For the first time, Lipari and its hydrothermal field are investigated by a seismic array recording continuously for about a month in late 2018 with a 0.1–1.5 km station spacing. We investigate the distribution and evolution of the seismicity over the full time of the experiment using self-organized maps and automatic algorithms. We show that the sea wave motion strongly influences the background seismic noise. Using an automatic template matching approach, we detect and locate a seismic swarm offshore the western coast of Lipari. This swarm, made of transient-like signals also recognized by array and polarization analyses in the time and frequency domains, is possibly associated with the activation of a NE-SW fault. We also found the occurrence of hybrid events close to the onshore Lipari hydrothermal system. These events suggest the involvement of hot hydrothermal fluids moving along pre-existing fractures. Seismological analyses of one month of data detect signals related to the regional tectonics, hydrothermal system and sea dynamics in Lipari Island.

Description: Published

Description: 678581

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Usually seismicity is intended as a natural phenomenon; yet the recording and interpretation of data are a human undertaking, historically conditioned. This research starts from the hypothesis that the decrease in Italian seismicity observed in the historical catalog [Rovida et al., 2021] for the central years of the twentieth century is due to the social and political conditioning that hindered its registration. This work, which focuses on the 1930s, with a brief excursion into previous years, presents part of the results obtained. In particular, the article deals with three earthquakes of which the data are substantially updated (Calabria, 7.03.1928; Alpi Noriche, 14.05.1930; Valli Giudicarie, 14.04.1931); then it presents an important replica of the strong Maiella earthquake, without macroseismic data in the catalog [Rovida et al., 2021], (Maiella, 23.11.1933); finally it considers a “forgotten” fifth earthquake (Southern Italy, 13.04.1938).

Description: Published

Description: 1-78

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Infrasonic signals investigation plays a fundamental role for both volcano monitoring purpose and the study of the explosion dynamics. Proper and reliable detection of weak signals is a critical issue in active volcano monitoring. In particular, in volcanic acoustics, it has direct consequences in pinpointing the real number of generated events (amplitude transients), especially when they exhibit low amplitude, are close in time to each other, and/or multiple sources exist. To accomplish this task, several algorithms have been proposed in literature; in particular, to overcome limitations of classical approaches such as short-time average/long-time average and cross-correlation detector, in this paper a subspace-based detection technique has been implemented. Results obtained by applying subspace detector on real infrasound data highlight that this method allows sensitive detection of lower energy events. This method is based on a projection of a sliding window of signal buffer onto a signal subspace that spans a collection of reference signals, representing similar waveforms from a particular infrasound source. A critical point is related to subspace design. Here, an empirical procedure has been applied to build the signal subspace from a set of reference waveforms (templates). In addition, in order to determine detectors parameters, such as subspace dimension and detection threshold, even in presence of overlapped noise such as infrasonic tremor, a statistical analysis of noise has been carried out. Finally, the subspace detector reliability and performance, have been assessed by performing a comparison among subspace approach, cross correlation detector and short-time average/long-time average detector. The obtained confusion matrix and extrapolated performance indices have demonstrated the potentiality, the advantages and drawbacks of the subspace method in tracking volcanic activity producing infrasound events. This method revealed to be a good compromise in detecting low-energy and very close in time events recorded during Strombolian activity

Description: Published

Description: 579923

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: The Istituto Nazionale di Geofisica e Vulcanologia (INGV) was born from the unification of public research institutions in the field of geophysics and volcanology. In the first twenty years from the foundation law of 1999, the INGV has seen a remarkable development, alternating moments of expansion, with significant increases in funding and number of employees, with long periods of stagnation. During these years the number of people hired with fixed-term contracts has grown, also to meet the needs of seismic and volcanic monitoring of the Italian territory, carried out on the basis of agreements with the Department of Civil Protection. After twenty years, it's time to outline a picture of the present situation and the evolutionary process that determined it. With this objective, the following analysis of the evolution of INGV was carried out in the period between its establishment and 2019, with reference to aspects such as the composition of the personnel, its distribution in the Sections, age, gender, role, career, with the aim of providing a tool for evaluating the progress made and planning future developments. The presence of a large number of precarious workers, distributed unevenly in territorial offices, for many years represented the main problem of the INGV, but not the only one. The contraction of the funding and the hiring freeze also slowed the development of the careers of researchers and other employers. The poor gender balance among the personnel, in particular among researchers, and the high average age represents further critical elements. The appropriate rebalancing of heterogeneities, aimed at maximum functionality and effective growth of the institute, should be the challenge for the next years. The future of INGV will depend on the choices that will be made today and the knowledge of the evolution of the institution until today is an essential element for proper programming.

Description: Published

Description: 1-92

Description: 3TM. Comunicazione

Description: JCR Journal

Description: Explosive eruptions are the surface manifestation of dynamics that involve transfer of magma from the underground regions of magma accumulation. Evidence of the involvement of compositionally different magmas from different reservoirs is continuously increasing to countless cases. Yet, models of eruption dynamics consider only the uppermost portion of the plumbing system, neglecting connections to deeper regions of magma storage. Here we show that the extent and efficiency of the interconnections between different magma storage regions largely control the size of the eruptions, their evolution, the causes of their termination, and ultimately their impact on the surrounding environment. Our numerical simulations first reproduce the magnitude-intensity relationship observed for explosive eruptions on Earth and explain the observed variable evolutions of eruption mass flow rates. Because deep magmatic interconnections are largely inaccessible to present-day imaging capabilities, our results motivate the need to better image and characterize extant magma bodies.

Description: Published

Description: 681083

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: In this paper the site categorization criteria and the corresponding site amplification factors proposed in the 2021 draft of Part 1 of Eurocode 8 (2021-draft, CEN/TC250/SC8 Working Draft N1017) are first introduced and compared with the current version of Eurocode 8, as well as with site amplification factors from recent empirical ground motion prediction equations. Afterwards, these values are checked by two approaches. First, a wide dataset of strong motion records is built, where recording stations are classified according to 2021-draft, and the spectral amplifications are empirically estimated computing the site-to-site residuals from regional and global ground motion models for reference rock conditions. Second, a comprehensive parametric numerical study of one-dimensional (1D) site amplification is carried out, based on randomly generated shear-wave velocity profiles, classified according to the new criteria. A reasonably good agreement is found by both approaches. The most relevant discrepancies occur for the shallow soft soil conditions (soil category E) that, owing to the complex interaction of shear wave velocity, soil deposit thickness and frequency range of the excitation, show the largest scatter both in terms of records and of 1D numerical simulations. Furthermore, 1D numerical simulations for soft soil conditions tend to provide lower site amplification factors than 2021-draft, as well as lower than the corresponding site-to-site residuals from records, because of higher impact of non-linear (NL) site effects in the simulations. A site-specific study on NL effects at three KiK-net stations with a significantly large amount of high-intensity recorded ground motions gives support to the 2021-draft NL reduction factors, although the very limited number of recording stations allowing such analysis prevents deriving more general implications. In the presence of such controversial arguments, it is reasonable that a standard should adopt a prudent solution, with a limited reduction of the site amplification factors to account for NL soil response, while leaving the possibility to carry out site-specific estimations of such factors when sufficient information is available to model the ground strain dependency of local soil properties.

Description: Published

Description: 4199–4234

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

Description: JCR Journal

Description: Ischia is a densely inhabited and touristic volcanic island located in the northern sector of the Gulf of Naples (Italy). In 2017, the Mw 3.9 Casamicciola earthquake occurred after more than one century of seismic quiescence characterized only by minor seismicity, which followed a century with three destructive earthquakes (in 1828, 1881, and 1883). These events, despite their moderate magnitude (Mw 〈 5.5), lead to dreadful effects on buildings and population. However, an integrated catalogue systematically covering historical and instrumental seismicity of Ischia has been still lacking since many years. Here, we review and systematically re-analyse all the available data on the historical and instrumental seismicity, to build an integrated earthquake catalogue for Ischia with a robust characterization of existing uncertainties. Supported by new or updated macroseismic datasets, we significantly enriched existing catalogues, as the Italian Parametric Earthquake Catalogue (CPTI15) that, with this analysis, passed from 12 to 57 earthquakes with macroseismic parametrization. We also extended back by 6 years the coverage of the instrumental catalogue, homogenizing the estimated seismic parameters. The obtained catalogue will not only represent a solid base for future local hazard quantifications, but also it provides the unique opportunity of characterizing the evolution of the Ischia seismicity over centuries. To this end, we analyse the spatial, temporal, and magnitude distributions of Ischia seismicity, revealing for example that, also in the present long-lasting period of volcanic quiescence, is significantly non-stationary and characterized by a b-value larger than 1.

Description: This work benefited of the agreement between Istituto Nazionale di Geofisica e Vulcanologia and the Italian Presidenza del Consiglio dei Ministri, Dipartimento della Protezione Civile (DPC).

Description: Published

Description: 629736

Description: 4T. Sismicità dell'Italia

Description: 6SR VULCANI – Servizi e ricerca per la società

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: 4IT. Banche dati

Description: JCR Journal

Description: ShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.

Description: Published

Description: 5391–5414

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

Description: JCR Journal

Description: This contribution illustrates the state of the art on the development of the multiparametric network in Sicily in the last three years. This region is wellknown for the strong earthquakes (M〉6.5) which struck in historic time. However, the coverage of the seismic network developed in the last decades was not fully optimized to the need of the seismic surveillance. Since 2017, the group belonging to the National Earthquake Observatory (ONT) which operates in Sicily launched a developing plan of the preexisting seismic network in the framework of the project FISR “Sale Operative Integrate e Reti di Monitoraggio del futuro: l’INGV 2.0 (S.O.I.R.)”. Such update will end by the next years thanks to the project “GRINT Italian Research Infrastructure for Geosciences” in the framework of the “Programma Operativo Nazionale” (PON) of the Italian Ministry for the University and Research. This plan envisages both the upgrade of monitoring systems in the already existing nodes, and the integration of new nodes. The main objective is to build a multiparametric network which integrates the main seismic network, with the monitoring of other geophysical signals through the implementation of other sensors: accelerometers, geodetic GPS, radon detectors, and corner reflectors. We also illustrate the plan for the realization of a redundant network which could support the tasks of the main infrastructure in case of failure of the latter. Finally, we present some experimental urbanscale networks which in the future could support the main infrastructure.

Description: Published

Description: 1-40

Description: 1IT. Reti di monitoraggio e sorveglianza

Description: JCR Journal

Description: The Aleutian Arc is remote and highly active volcanically. Its 4,000 km extent from mainland Alaska to Russia’s Kamchatka peninsula hosts over 140 volcanic centers of which about 50 have erupted in historic times. We present data of volcanic gas samples and gas emission measurements obtained during an expedition to the western-most segment of the arc in September 2015 in order to extend the sparse knowledge on volatile emissions from this remote but volcanically active region. Some of the volcanoes investigated here have not been sampled for gases before this writing. Our data show that all volcanoes host high-temperature magmatic-hydrothermal systems and have gas discharges typical of volcanoes in oceanic arcs. Based on helium isotopes, the western Aleutian Arc segment has minimal volatile contributions from the overriding crust. Volcanic CO2 fluxes from this arc segment are small, compared to the emissions from volcanoes on the Alaska Peninsula and mainland Alaska. The comparatively low CO2 emissions may be related to the lower sediment flux delivered to the trench in this part of the arc.

Description: Published

Description: 786021

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: JCR Journal

Description: We present results from a joint inversion of new seismic and recently compiled gravity data to constrain the structure of a prominent geophysical anomaly in the European Alps: the Ivrea Geophysical Body (IGB). We investigate the IGB structure along the West-East oriented Val Sesia profile at higher resolution than previous studies. We deployed 10 broadband seismic stations at 5 km spacing for 27 months, producing a new database of ∼1000 high-quality seismic receiver functions (RFs). The compiled gravity data yields 1 gravity point every 1–2 km along the profile. We set up an inversion scheme, in which RFs and gravity anomalies jointly constrain the shape and the physical properties of the IGB. We model the IGB’s top surface as a single density and shear-wave velocity discontinuity, whose geometry is defined by four, spatially variable nodes between far-field constraints. An iterative algorithm was implemented to efficiently explore the model space, directing the search toward better fitting areas. For each new candidate model, we use the velocity-model structures for both ray-tracing and observed-RFs migration, and for computation and migration of synthetic RFs: the two migrated images are then compared via cross-correlation. Similarly, forward gravity modeling for a 2D density distribution is implemented. The joint inversion performance is the product of the seismic and gravity misfits. The inversion results show the IGB protruding at shallow depths with a horizontal width of ∼30 km in the western part of the profile. Its shallowest segment reaches either 3–7 or 1–3 km depth below sea-level. The latter location fits better the outcropping lower crustal rocks at the western edge of the Ivrea-Verbano Zone. A prominent, steep eastward-deepening feature near the middle of the profile, coincident with the Pogallo Fault Zone, is interpreted as inherited crustal thickness variation. The found density and velocity contrasts of the IGB agree with physical properties of the main rock units observed in the field. Finally, by frequency-dependent analysis of RFs, we constrain the sharpness of the shallowest portion of the IGB velocity discontinuity as a vertical gradient of thickness between 0.8 km and 0.4 km.

Description: The Swiss National Science Foundation (SNF) supported this research (grant numbers PP00P2_157627 and PP00P2_187199 of project OROG3NY), as well as the Grant Agency of the Czech Republic (No. 21-25710). The project CzechGeo/EPOS No. LM2015079 of the MEYS funded the MOBNET station pool.

Description: Published

Description: 671412

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: Studying seismicity in a volcanic environment provides important information on the state of activity of volcanoes. The seismicity of the Neapolitan volcanoes, Campi Flegrei, Vesuvius, and Ischia, shows distinctive characteristics for each volcano, coveringwide range of patterns and types. In this study we relocated some significant volcano- tectonic earthquake swarms that occurred in Campi Flegrei and Vesuvius. Moreover, we compared the earthquake occurrence evolution, the magnitude and the seismic energy release of the three volcanoes. Also, we considered the results of seismic analysis in the light of geochemical and ground deformation data that contribute to defining the state of activity of volcanoes. In Campi Flegrei, which is experiencing a long term unrest, we identified a seismogenic structure at shallow depth in Pisciarelli zone that has been activated repeatedly. The increasing seismicity accompanies an escalation of the hydrothermal activity and a ground uplift phase. At Vesuvius a very shallow seismicity is recorded, which in recent years has shown an increase in terms of the number of events per year. Earthquakes are usually located right beneath the crater axis. They are concentrated in a volume affected by the hydrothermal system. Finally, Ischia generally shows a low level of seismicity, however, in Casamicciola area events with a moderate magnitude can occur and these are potentially capable of causing severe damage to the town and population, due to their small hypocentral depth (typically 〈 2.5 km). After the seismic crisis of August 21, 2017 (mainshock magnitude M 4), the seismicity returned to a low level in terms of occurrence rate and magnitude of earthquakes. The seismicity of these three different volcanic areas shows some common aspects that highlight a relevant role of hydrothermal processes in the seismogenesis of volcanic areas. However, while the main swarms in Campi Flegrei and most of the Vesuvian earthquakes are distributed along conduit-like structures, the seismicity of Ischia is mainly located along faults. Furthermore, the temporal evolution of seismicity in Neapolitan volcanic area suggests a concomitant increase in the occurrence of earthquakes both in Campi Flegrei and Vesuvius in recent years.

Description: Published

Description: 662113

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: Dissolved gases in the deep water of lakes can pose a safety hazard when extreme concentrations are reached. A sudden release of large amounts of gas can cost the lives of humans living in the neighbourhood, as has happened at Lake Nyos in 1986. Since 2001, Lake Nyos gas risk has been mitigated by induced degassing, but the connection to the gas source is still in place and a regular survey needs to be implemented to guarantee safe conditions. Frequent sampling at the remote location of Lake Nyos requires an enormous effort and many analytical techniques are nearly impossible to run at the lake site. In this contribution, we combined a commercially available sound speed sensor with a CTD (conductivity-temperature-depth) probe to gain an indirect but quantitative estimate of carbon dioxide concentrations at fine depth resolution (decimeter scale). Dissolved carbon dioxide increases sound speed but does not contribute to electrical conductivity. Hence the difference between measured and calculated (on the base of electrical conductivity, temperature and pressure) and measured sound speed gives a quantitative indication of dissolved carbon dioxide. We highly recommend the implementation of the sound speed-CTD probe combination, at Lake Nyos, or at other gas-laden volcanic lakes, as it could safeguard the people living in the area with acceptable cost and effort for the operators, when alarming CO2 concentrations in deep lake strata will be timely detected.

Description: Published

Description: 645011

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: Extreme events have long been underestimated in the extent to which they shape the surface of our planet, our environment, its ecological integrity, and the sustainability of human society. Extreme events are by definition rarely observed, of significant impact and, as a result of their spatiotemporal range, not always easily predicted. Extremes may be short-term catastrophic events such as tsunamis, or long-term evolving events such as those linked to climate change; both modify the environment, producing irreversible changes or regime shifts. Whatever the driver that triggers the extreme event, the damages are often due to a combination of several processes and their impacts can affect large areas with secondary events (domino effect), whose effects in turn may persist well beyond the duration of the trigger event itself. Early studies of extreme events were limited to opportunistic approaches: observations were made within the context of naturally occurring events with high societal impact. Given that climate change is now moving us out of a relatively static climate regime during the development of human civilization, extreme events are now a function of underlying climate shifts overlain by catastrophic processes. Their impacts are often due to synergistic factors, all relevant in understanding process dynamics; therefore, an integrated methodology has become essential to enhance the reliability of new assessments and to develop strategies to mitigate societal impacts. Here we summarize the current state of extreme event monitoring in the marine system, highlighting the advantages of a multidisciplinary approach using Research Infrastructures for providing the temporal and spatial resolution required to monitor Earth processes and enhance assessment of associated impacts.

Description: Published

Description: 626668

Description: 3A. Geofisica marina e osservazioni multiparametriche a fondo mare

Description: JCR Journal

Description: In this Research Topic, we aimed to contribute to the ongoing scientific progress and the process of assessing and providing community-based standards, good practices, benchmarking tools and guidelines, based on the most recent observations and scientific findings. This purpose is in line with several community-based efforts like those of the “GTM—Global Tsunami Model” and “AGITHAR—Accelerating Global science In Tsunami Hazard and Risk analysis” scientific networks. We aimed to help better address the link between tsunami science and the Probabilistic Tsunami Hazard and Risk Analysis. This Topic includes numerous Original Research papers, one Brief Research Report and one Review. Overall, we gathered 20 articles contributed by more than 200 authors. We consider this a strong indication from the research community.

Description: Published

Description: 764922

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

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

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: 1SR TERREMOTI - Sorveglianza Sismica e Allerta Tsunami

Description: JCR Journal

Description: The lava platform and the three pyroclastic cones of Vulcanello constitute the northernmostvolcanic structure of the island of Vulcano (Aeolian Islands). The sandy isthmus connecting theplatform to the main island was definitively formed in the first half of the 1500s; before then,Vulcano and Vulcanello were two close but separate islands. For a long time, the interpretation ofthe sources of the II-I century BC, had considered the islet as built up about 2200 years ago. Thisbelief, which proliferated among naturalists from the 17th century, is not confirmed in the ancienttexts or even in the geographical documents of the time, which do not indicate the presence ofVulcanello as a new and stable island near Vulcano. The islet would only be mentioned at the dawnof the second millennium, and named in Arabic “Gabal’ al Burkān”, meaning Mount of Vulcano;shortly thereafter the toponym changed to the Latin “Insulam Vulcanelli” and then, towards the15th century, finally to Vulcanello.Since the creation of a volcanic island certainly occurred in the Aeolian Islands in the classical era,but traces of it were quickly lost, the most plausible hypothesis is that it was formed in the area ofthe current Vulcanello, to be subsequently erased by the sea. The shallow, flat seabed, likelyremaining as a result of sea abrasion, might have represented the morphological element on whichthe circular lava platform we know today was formed sometime between 950 and 1000 AD.

Description: Published

Description: VO548

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: Space techniques based on GPS and SAR interferometry allow measuringmillimetric ground deformations. Achieving such accuracy means removing atmospheric anomalies that frequently affect volcanic areas by modeling the tropospheric delays. Due to the prominent orography and the high spatial and temporal variability of weather conditions, the active volcano Mt. Etna (Italy) is particularly suitableto carry out research aimed at estimating and filtering atmospheric effects on GPS and DInSAR grounddeformation measurements. The aim of this work is to improve the accuracy of the ground deformation measurements by modeling the tropospheric delays at Mt. Etna volcano. To this end, data from the monitoring network of 29 GPS permanent stations and MODIS multispectral satellite data series are used to reproduce the tropospheric delays affecting interferograms. A tomography algorithm has been developed to reproduce the wet refractivityfield over Mt. Etna in 3D, starting from the slant tropospheric delays calculated by GPS in all the stations of the network. The developed algorithm has been tested on a synthetic atmospheric anomaly. The test confirms the capability of the software to faithfully reconstruct the simulated anomaly. With the aim of applying this algorithm to real cases, we introduce the water vapor contentmeasured by the MODIS instrument on board Terra and Aqua satellites. The use of such data,although limited by cloud cover, provides a two-fold benefit: it improves the tomographic resolution and adds feedback for the GPS wet delay measurements. A cross-comparison between GPS and MODIS water vapor measurements for thefirst time shows a fair agreement between those indirect measurements on an entire year of data (2015). The tomography algorithm was applied on selected real cases to correct the Sentinel-1 DInSAR interferograms acquired over Mt. Etna during 2015. Indeed, the corrected interferograms show that the differential path delay reaches 0.1 m (i.e. 3 C-band fringes) in ground deformation, demonstrating how the atmospheric anomaly affects precision and reliability of DInSAR space-based techniques. The real cases show that the tomography is often able to capturethe atmospheric effect at the large scale and correct interferograms, although in limited areas. Furthermore, the introduction of MODIS data significantly improves by ∼80% voxel resolution at the critical layer (1,000 m). Further improvements will be suitable for monitoring active volcanoes worldwide.

Description: Published

Description: 510514

Description: 5IT. Osservazioni satellitari

Description: JCR Journal

Description: Changbaishan volcano (China/North Korea border) consists of a cone with a summit caldera and last erupted in 1903. An unrest episode occurred between 2002 and 2006, followed by subsidence. The volcano was responsible for the largest eruption of the last Millennium in 946 CE and it is characterized by a multi-level plumbing system. Here, we analyze the Changbaishan 2018-2020 deformations by using remote sensing data, detecting an up to 20 mm/yr, NW-SE elongated nearly-uplift of its southeastern flank and a -20 mm/yr nearly-subsidence of the southwestern flank. Modeling results show that three active sources are responsible for the observed ground velocities: a deep tabular deflating source, a shallower inflating NW-SE elongated spheroid source, and a NW-SE striking dip-slip fault. The depth and geometry of the inferred sources are consistent with independent petrological and geophysical data. Our results reveal an upward magma migration from 14 km to 7.7 km. The modeling of the leveling data of the 2002-2005 uplift and 2009-2011 subsidence depicts sources consistent with the 2018-2020 active system retrieved. The past unrest is related to pressurization of the upper portion of the spheroid magma chamber, whereas the subsidence is due to crystallization of its floor, this latter reactivated in 2018-2020. Therefore, Changbaishan is affected by an active magma recharge controlled by a NW-SE trending fault system. Satellite data analysis is a key tool to unravel the magma dynamics at poorly monitored and crossborder volcanoes.

Description: Published

Description: 741287

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: Il mondo della Ricerca e dell ’Innovazione Tecnologica per sua natura è sempre in evoluzione, ed accompagnato da normative in materia di Sicurezza e Salute non sempre conosciute o applicate. La particolare enfasi data alla formazione nel quadro normativo riguardante la Sicurezza e Salute nei luoghi di lavoro, sia a livello nazionale che comunitario, dimostra e determina l’importanza attribuita a tale processo, non solo come mezzo elettivo per la diffusione della cultura della Sicurezza a tutti i livelli , ma anche, e soprattutto, come misura generale di tutela.

Description: Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 1-54

Description: 1TM. Formazione

Description: N/A or not JCR

Description: Analyzing seismic data to get information about earthquakes has always been a major task for seismologists and, more in general, for geophysicists. Recently, thanks to the technological development of observation systems, more and more data are available to perform such tasks. However, this data “grow up” makes “human possibility” of data processing more complex in terms of required efforts and time demanding. That is why new technological approaches such as artificial intelligence are becoming very popular and more and more exploited. In this paper, we explore the possibility of interpreting seismic waveform segments by means of pre-trained deep learning. More specifically, we apply convolutional networks to seismological waveforms recorded at local or regional distances without any pre-elaboration or filtering. We show that such an approach can be very successful in determining if an earthquake is “included” in the seismic wave image and in estimating the distance between the earthquake epicenter and the recording station.

Description: Published

Description: 1347–1359

Description: 1T. Struttura della Terra

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: Themain climatological features of the ionospheric equivalent slab thickness (τ ) for the Northern hemispheremidlatitudes are analyzed. F2-layer peak electron density values recorded at three midlatitude ionospheric stations (Chilton 51.5° N, 0.6° W, U.K.; Roquetes 40.8° N, 0.5° E, Spain;Wallops Island 37.9° N, 75.5°W, USA) and vertical total electron content values from colocated ground-based Global Navigation Satellite System receivers are used to calculate a dataset of τ values for the last two solar cycles, considering only magnetically quiet periods. Results are presented both as grids of binned medians and as boxplots as a function of local time and month of the year, for different solar activity levels. Corresponding trends are first compared to those output by the midlatitude empirical model developed by Fox et al. (Radio Sci 26:429–438, 1991) and then discussed in the light of what is known so far. From this investigation, the strong need to implement an improved empirical model of τ has emerged. Both Space Weather and Space Geodesy applications might benefit from such model. Therefore, both the dataset and the methodology described in the paper represent a first fundamental step aimed at implementing an empirical climatological model of the ionospheric equivalent slab thickness. The study highlighted also that at midlatitudes τ shows the following main patterns: daytime values considerably smaller than nighttime ones (except in summer); well-defined maxima at solar terminator hours; a greater dispersion during nighttime and solar terminator hours; no clear and evident solar activity dependence.

Description: Published

Description: 124

Description: 2A. Fisica dell'alta atmosfera

Description: JCR Journal

Description: Within a fault governing model the characteristic scale length is one of the most relevant physical parameters because it accounts for the so–called fracture energy (density) of the system, its dynamics, the time during which the accumulated stress is released and the seismic waves are excited, the amount of slip developed during an instability event. Friction laboratory experiments reveal that it is not a material property, but that it changes with the sliding velocity. We propose two rather different analytical models to fit laboratory evidence and we incorporate them into a fault model able to simulate repeated earthquakes in the framework of various formulations of rate and state friction. We demonstrate that temporal variations of the scale length do not prevent the system to reach its limit cycle, but they systematically reduce the magnitude of the expected event (both in term of developed slip, and thus seismic moment, and released stress) and also reduce the inter–event time (recurrence interval). Depending on the friction model, the system can penetrate into the stable regime and can either continue the accelerating phase toward to failure or decelerate and abort instability.

Description: Published

Description: SE217

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: The eruption of basaltic magmas dominates explosive volcanism on Earth and other planets within the Solar System. The mechanism through which continuous magma fragments into volcanic particles is central in governing eruption dynamics and the ensuing hazards. However, the mechanism of fragmentation of basaltic magmas is still disputed, with both viscous and brittle mechanisms having been proposed. Here we carry out textural analysis of the products of ten eruptions from seven volcanoes by scanning electron microscopy. We find broken crystals surrounded by intact glass that testify to the brittle fragmentation of basaltic magmas during explosive activity worldwide. We then replicated the natural textures of broken crystals in laboratory experiments where variably crystallized basaltic melt was fragmented by rapid deformation. The experiments reveal that crystals are broken by the propagation of a network of fractures through magma, and that afterwards the fractures heal by viscous flow of the melt. Fracturing and healing affect gas mobility, stress distribution, and bubble and crystal size distributions in magma. Our results challenge the idea that the grain size distribution of basaltic eruption products reflects the density of fractures that initially fragmented the magma and ultimately indicate that brittle fracturing and viscous healing of magma may underlie basaltic explosive eruptions globally.

Description: Published

Description: 248–254

Description: 4V. Processi pre-eruttivi

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: The understanding of the ancient Earth’s Magnetic Field strength, or absolute paleointensity, is fundamental for several disciplines of Earth Sciences. Following the growing interest in this field in the last decades, the number of paleointensity studies has been increasing and the Paleomagnetic Laboratory of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Rome, Italy expanded the instrument park with a ASC TD48SC oven for paleomagnetic and paleointensity measurements. This manual represents an updated version of the original manual “Guida all’uso del forno ASC TD48SC per la stima della paleointensità assoluta con il metodo ThellierThellier modificato” [Di Chiara, 2014]. The aim is to provide a practical guide for paleointensity measurements, using the IZZIThellier experiment and the software Thellier_GUI for the processing of the geomagnetic field strength or paleointensity data.

Description: INGV

Description: Published

Description: 1-20

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: N/A or not JCR

Description: We describe the geochemical characteristics of groundwater samples collected in 23 water wells located on the northern margin of the Hyblean plateau (East Sicily). This area, mostly made of highly permeable carbonate rocks, is rich in low temperature (T 〈 50° C) hydrothermal groundwaters, distributed in an active sismogenetic zone, with several ENE-WSW-directed tectonic structures that drove magma to the surface during Upper Pliocene and Pleistocene. The chemical features suggest complex mixing between rainwater, CO2-rich groundwater, steam-heated groundwater and geothermal brines, as highlighted by Principal Component Analysis (PCA). Some parameters, however, indicate widespread pollution of the aquifers from human activities. Stable isotopes analysis confirms the meteoric origin of groundwater and supports the origin of dissolved CO2 mostly from mantle degassing through deep tectonic faults. Geothermometric estimates, mostly based on quartz and Saturation Indexes geothermometers, suggest minimum reservoir temperature between 100 and 120° C.

Description: Published

Description: HS438

Description: 1TR. Georisorse

Description: JCR Journal

Description: 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.

Description: Published

Description: PE108

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: The traction evolution is a fundamental ingredient to model the dynamics of an earthquake rupture which ultimately controls, during the coseismic phase, the energy release, the stress redistribution and the consequent excitation of seismic waves. In the present paper we explore the use of the friction behavior derived from laboratory shear experiments performed on granular materials at low normal stress. We find that the rheological properties emerging from these laboratory experiments can not be described in terms of preexisting governing models already presented in literature; our results indicate that neither rate–and state–dependent friction laws nor nonlinear slip–dependent models, commonly adopted for modeling earthquake ruptures, are able to capture all the features of the experimental data. Then, by exploiting a novel numerical approach, we directly incorporate the laboratory data into a code to simulate the fully dynamic propagation of a 3–D slip failure. We demonstrate that the rheology of the granular material, imposed as fault boundary condition, is dynamically consistent. Indeed, it is able to reproduce the basic features of a crustal earthquake, spontaneously accelerating up to some terminal rupture speed, both sub– and supershear.

Description: Published

Description: SE441

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: JCR Journal

Description: INGV

Description: Published

Description: 1-18

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: N/A or not JCR

Description: In the last decade, bottom-up strategies of risk education have raised importance, making seriousgames to become an alternative or complementary teaching tool for enhancing skills for acollaborative and adaptive response to social-ecological challenges. This study describes issues and challenges of serious games implemented within the framework oftwo European projects, namely UPStrat-MAFA (Urban Disaster Prevention Strategies usingMacroseismic Fields and FAult sources) and KnowRISK (Know your city, Reduce seISmic risKthrough non-structural elements); the goal is to instil in young people a proactive attitude towardsthe mitigation of seismic risk. The games were tested in some dissemination events focussed on fostering seismic riskpreparedness in students and improving good practices. We discuss the performance of our gameseven against more standard approaches to risk education. Our experience shows a rise of students’engagement compared to standard learning activities. The games were effective as students wereable to grasp the most relevant actions to reduce risk

Description: Published

Description: SE327

Description: 2TM. Divulgazione Scientifica

Description: JCR Journal

Description: The ocean is a crucial component of the Earth’s climate system. Heat and CO2 are absorbed in the ocean’s surface and transported throughout the ocean depths through the overturning circulation. Exchange across the ocean’s turbulent surface boundary layer can happen rapidly, in hours or days, and significant exchange of water between the boundary layer and the stratified main thermocline occurs over timescales of years to decades. Deepwater takes many decades to millennia to return to the surface, acting as long-term storage for heat and CO2 and thereby lessening the near-term impacts of climate change. The understanding of mechanisms and rates that control the bottom flows is essential to quantify re-transfer towards the upper layers of the energy stored at the seafloor. These processes are significantly affecting the ocean system as a whole and could contribute to accelerating the rising climate trends (thermohaline circulation, sea-level rise, and ocean acidification). The Mediterranean Sea, like the ocean, has its overturning circulation and it represents a suitable lab for investigating physical mechanisms such as deepwater formation, mixing processes, strait dynamics, advective-convective feedbacks that drive the ocean variability, and the internal exchange mechanisms. Also, the scale of variability is shorter compared to other ocean basins in time and space. As mechanisms governing exchanges of heat and carbon in the ocean occur with long timescales, observational datasets over many decades are required to document, understand, and predict the climate system as a whole. This is also an essential requirement to detect and attribute changes driven by human activities and to predict how the climate system will likely behave in the future. The needs for and uses of deep ocean data extend well beyond closing the global heat budget. Deep ocean data are needed to initialize and constrain ocean models and improve their representation of mixing of heat downwards/upwards within the deep ocean. In order to understand past and future climate changes, the characterization of the still unexplored deep dynamics aims to provide crucial results to support new interpretations of the paleo circulation and of those processes that have influenced ventilation and water masses overturning. These new insights will also be essential for leading, in the near future, new tailored parameterizations able to adequately represent the dynamics below 2000m of depth. This article collection conceived in the framework of MedCliver (http://www.medclivar.eu/) community, aims to gather outcomes on deep ocean circulation and bottom mixing not only in the Mediterranean area but also through other important case studies relevant in the characterization of deep processes, considering three different points of view: 1- Theoretical (role of the bottom diffusion) 2- New assimilation and modeling 3- In situ observations of deep long time series These will contribute to improving knowledge of the impacts of key deep processes on the climate system.

Description: Published

Description: 801479

Description: 4A. Oceanografia e clima

Description: JCR Journal

Description: The structure of an active volcano is highly dependent on the interplay between the geodynamic context, the tectonic assessment as well as the magmatic processes in the plumbing system. This complex scenario, widely explored at Etna during the last 40 years, is nevertheless incomplete for the recent historical activity. In 1763 two eruptions occurred along the west flank of the volcano. There, an eruption started on 6th February and formed the scoria cone of Mt. Nuovo and a roughly 4-km-long lava flow field. Another small scoria cone, known as Mt. Mezza Luna, is not dated in historical sources. It is located just 1 km eastward of Mt. Nuovo and produced a 700mlong flow field. We focused on the activity of Mts. Nuovo and Mezza Luna for several reasons. First, the old geological maps and volcanological catalogues indicate that Mt. Mezza Luna and Mt. Nuovo cones were formed during the same eruption, while historical sources described Mt. Nuovo’s activity as producing a single scoria cone and do not give information about the formation of Mt. Mezza Luna. Second, petrologic studies highlight that the products of Mt. Mezza Luna are similar to the sub-aphyric Etna basalts; they preserve a composition relatively close to Etna primitive magma which were also erupted in 1763, during La Montagnola flank eruption, which took place along the South Rift of the volcano. Third, the two scoria cones built up along the so-called West Rift of Etna, which represents one of the main magma-ascent zones of the volcano. We applied a multidisciplinary approach that could prove useful for other volcanoes whose past activity is still to be reconstructed. Critical reviews of historical records, new field surveys, petrochemical analyses and petrologic modelling of the Mts. Nuovo and Mezza Luna eruptions have been integrated with literature data. The results allowed improving the stratigraphic record of historical eruptions reported in the Mount Etna Geological map, modelling the sub-volcanic magmatic processes responsible for magma differentiation, and evidencing recurrent mechanisms of magma transfer at Etna. Indeed, the intrusion of a deep primitive magma along the South Rift is often associated with the activation of other rift zones that erupt residual magma stored in the shallow plumbing system.

Description: This study has been funded by the EC FP7 Mediterranean Supersite Volcanoes project (ECGA 308665) of the European Commission

Description: Published

Description: 774361

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: A first combined absolute gravity and GNSS network of 5 stations distributed between Lazio, Umbria and Abruzzo regions, was realized in 2018 in order to lay the basics for a multidisciplinary approach to natural risk assessment in the area of Central Italy, affected by the 2009 and 2016 seismic activity. Up to now, two absolute gravity campaigns were carried out using the transportable Microg LaCoste FG5#238 and the portable A10#39 absolute gravimeters. The locations of gravimetric sites have been chosen indoor to allow optimal condition of measure; therefore, the heights of the indoor sites have been determined by joining the outdoor GNSS with classical topographic surveys. The good results obtained after the campaigns and data processing lay the foundations for a new multidisciplinary approach to study also seismogenetic areas. In this paper, we present the gravity and GNSS station monographs, together with the absolute gravity values and the coordinates resulting from the first field surveys.

Description: Published

Description: 1-26

Description: 4T. Sismicità dell'Italia

Description: JCR Journal

Description: Volcanic activity resumed during early Middle Ages times at Lipari following at least 6000 years of quiescence. This phenomenon occurred in a social context that had continuously developed from prehistoric times to the Roman age and was burdened by a demographic crisis that involved the archipelago between the 6th and 11th century AD. The rare archaeological records relating to the 6th - 11th centuries suggest abrupt changes in the population of the islands. The medieval sources are rich in religious and fantastic references to volcanic events linked to Lipari and Vulcano, testifying the uneasy condition for the human communities. This work concerns the resilience and adaptation of the communities to volcanic activity during the Late Middle Ages in Lipari. Starting from 1083 the Aeolian archipelago was involved in a repopulation program, implemented in 1095 by the Constitutum and organized by the Benedictine Monastery with the annexed S. Bartolomeo Cathedral on the castle. From the 13th century the volcanic phenomena, strictly limited to the northern sector of the island, did not interfere as previously with the anthropic activities. The Monastery will be enlarged in the Norman phase during the first half of the 12th century with the construction of the cloister. New historical documents relating to the 1264, report news of fires and land movements on Lipari. Recent age determinations obtained for the obsidian flow of Rocche Rosse at 1220 ± 30 AD (archaeomagnetic dating) and for an obsidian block of the Lami pyroclastic cone at 1243 ± 190 (fission-track dating) allow to define the age of the last phase of activity of the Monte Pilato-Lami-Rocche Rosse complex, and to associate it the events reported on 1264’s historical documents. This work makes in comparison volcanological, archaeological and historical dates and described an updated summary of one of the lesser known phases of the history of the archipelago. The main consequence of the medieval volcanic activity at Lipari caused a clear division of the territory with the population confined in the southeast quadrant, protected to the north by Serra and Monte Rosa which represented a natural orographic barrier.

Description: Published

Description: VO549

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: This book serves as a guide to discovering the most interesting volcano sites in Italy. Accompanied by some extraordinary contemporary images of active Neapolitan volcanoes, it explains the main volcanic processes that have been shaping the landscape of the Campania region and influencing human settlements in this area since Greek and Roman times and that have prompted leading international scientists to visit and study this natural volcanology laboratory. While volcanology is the central topic, the book also addresses other aspects related to the area’s volcanism and is divided into three sections: 1) Neapolitan volcanic activity and processes (with a general introduction to volcanology and its development around Naples together with descriptions of the landscape and the main sites worth visiting); 2) Volcanoes and their interactions with local human settlements since the Bronze Age, recent population growth and the transformation of the territory; 3) The risks posed by Neapolitan Volcanoes, their recent activity and the problem of forecasting any future eruption.

Description: Published

Description: 2TM. Divulgazione Scientifica

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Babbin, A. R., Tamasi, T., Dumit, D., Weber, L., Rodríguez, M. V. I., Schwartz, S. L., Armenteros, M., Wankel, S. D., & Apprill, A. Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals. ISME Journal, (2020), doi:10.1038/s41396-020-00845-2.

Description: Coral reef health depends on an intricate relationship among the coral animal, photosynthetic algae, and a complex microbial community. The holobiont can impact the nutrient balance of their hosts amid an otherwise oligotrophic environment, including by cycling physiologically important nitrogen compounds. Here we use 15N-tracer experiments to produce the first simultaneous measurements of ammonium oxidation, nitrate reduction, and nitrous oxide (N2O) production among five iconic species of reef-building corals (Acropora palmata, Diploria labyrinthiformis, Orbicella faveolata, Porites astreoides, and Porites porites) in the highly protected Jardines de la Reina reefs of Cuba. Nitrate reduction is present in most species, but ammonium oxidation is low potentially due to photoinhibition and assimilatory competition. Coral-associated rates of N2O production indicate a widespread potential for denitrification, especially among D. labyrinthiformis, at rates of ~1 nmol cm−2 d−1. In contrast, A. palmata displays minimal active nitrogen metabolism. Enhanced rates of nitrate reduction and N2O production are observed coincident with dark net respiration periods. Genomes of bacterial cultures isolated from multiple coral species confirm that microorganisms with the ability to respire nitrate anaerobically to either dinitrogen gas or ammonium exist within the holobiont. This confirmation of anaerobic nitrogen metabolisms by coral-associated microorganisms sheds new light on coral and reef productivity.

Description: Research was conducted in the Gardens of the Queen, Cuba in accordance with the requirements of the Republic of Cuba, conducted under permit NV2370 and NV2568 issued by the Ministerio de Relaciones Exteriores. We gratefully acknowledge funding for this research by MIT Sea Grant award #2018-DOH-49-LEV, Simons Foundation award #622065, and MIT ESI seed funding to ARB, the MIT Montrym, Ferry, and mTerra Seed Grant Funds, and the generous contributions by Dr Bruce L. Heflinger.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Seyler, L. M., Trembath-Reichert, E., Tully, B. J., & Huber, J. A. Time-series transcriptomics from cold, oxic subseafloor crustal fluids reveals a motile, mixotrophic microbial community. Isme Journal, (2020), doi:10.1038/s41396-020-00843-4.

Description: The oceanic crustal aquifer is one of the largest habitable volumes on Earth, and it harbors a reservoir of microbial life that influences global-scale biogeochemical cycles. Here, we use time series metagenomic and metatranscriptomic data from a low-temperature, ridge flank environment representative of the majority of global hydrothermal fluid circulation in the ocean to reconstruct microbial metabolic potential, transcript abundance, and community dynamics. We also present metagenome-assembled genomes from recently collected fluids that are furthest removed from drilling disturbances. Our results suggest that the microbial community in the North Pond aquifer plays an important role in the oxidation of organic carbon within the crust. This community is motile and metabolically flexible, with the ability to use both autotrophic and organotrophic pathways, as well as function under low oxygen conditions by using alternative electron acceptors such as nitrate and thiosulfate. Anaerobic processes are most abundant in subseafloor horizons deepest in the aquifer, furthest from connectivity with the deep ocean, and there was little overlap in the active microbial populations between sampling horizons. This work highlights the heterogeneity of microbial life in the subseafloor aquifer and provides new insights into biogeochemical cycling in ocean crust.

Description: The Gordon and Betty Moore Foundation sponsored most of the observatory components at North Pond through grant GBMF1609. This work was supported by NSF OCE-1062006, OCE-1745589 and OCE-1635208 to J.A.H. E.T.R. was supported by a NASA Postdoctoral Fellowship with the NASA Astrobiology Institute and a L’Oréal USA For Women in Science Fellowship. The Center for Dark Energy Biosphere Investigations (C-DEBI OCE-0939564) also supported the participation of J.A.H. and B.T. This is C-DEBI contribution number 548.

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Coskun, O. K., Vuillemin, A., Schubotz, F., Klein, F., Sichel, S. E., Eisenreich, W., & Orsi, W. D. Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. Isme Journal. (2021), https://doi.org/10.1038/s41396-021-01066-x.

Description: Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.

Description: This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project-ID 364653263—TRR 235 to WDO and WE, and under Germany’s Excellence Strategy—EXC 2077-390741603. The work was also supported by the Dalio Explore Fund and LMU Mentoring Program. Open Access funding enabled and organized by Projekt DEAL.

Description: Single-type hazard and risk assessment is the usual framework followed by disaster risk reduction (DRR) practitioners. There is therefore a need to present and compare the results arising from different hazard and risk types. Here we describe a simple method for combining risk curves arising from different hazard types in order to gain a first impression of the total risk. We show how the resulting total (and individual) risk estimates can be examined and compared using so-called risk matrices, a format preferred by some DRR practitioners. We apply this approach to Cologne, Germany, which is subject to floods, windstorms and earthquakes. We then use a new series of risk calculations that consider epistemic uncertainty. The Mann-Whitney test is applied to determine if the losses arising from pairs of hazards are comparable for a given return period. This benefits decision makers as it allows a ranking of hazards with respect to expected damage. Such a comparison would assist planners in the allocation of resources towards the most efficient mitigation actions. However, the results are dependent upon the distribution of estimates (i.e., level of uncertainty), which is in turn a function of our state of knowledge.

Description: Published

Description: S0216

Description: 7SR AMBIENTE – Servizi e ricerca per la società

Description: JCR Journal

Description: In this paper we present an updated and homogeneous earthquake dataset for Italy compiled by joining the intensities available in the Italian Macroseismic Database DBMI15 and the peak ground motion (PGM) parameters present in the Engineering Strong-Motion (ESM) accelerometric data bank. The database has been compiled through an extensive procedure of evaluation and revision based on two main steps: 1) the selection of the earthquakes in DBMI15 with homogeneous macroseismic intensities in terms of data sources and 2) the extraction of all the localities reporting intensity data which are located within 3 km from the accelerograph stations that recorded the data. The final dataset includes 519 intensity-PGM data pairs from 65 earthquakes and 227 stations in the time span 1972–2016. The reported intensities are expressed either in the Mercalli-Cancani-Sieberg (MCS) or the European macroseismic (EMS-98) scales. The events are characterized by magnitudes in the range 4.1–6.8 and depths in the range 0–55 km. Here, we illustrate the data collection and the properties of the database in terms of recording, event and station distributions as well as macroseismic intensity points. Furthermore, we discuss the most relevant features of engineering interest showing several statistics with reference to the most significant metadata (such as moment magnitude, several distance metrics, style of faulting etc). The dataset is expected to be useful for benchmarking existing and for developing new ground motion intensity conversion equations offering a common basis, and sparing the time and effort required for assembling to the interested researchers. The dataset is available at https://zenodo.org/record/4623732#.YNX-AZMzbdc.

Description: Published

Description: DM102

Description: 4IT. Banche dati

Description: JCR Journal

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Castro, S. P., Borton, M. A., Regan, K., de Angelis, I. H., Wrighton, K. C., Teske, A. P., Strous, M., & Ruff, S. E. Degradation of biological macromolecules supports uncultured microbial populations in Guaymas Basin hydrothermal sediments. Isme Journal. (2021), https://doi.org/10.1038/s41396-021-01026-5.

Description: Hydrothermal sediments contain large numbers of uncultured heterotrophic microbial lineages. Here, we amended Guaymas Basin sediments with proteins, polysaccharides, nucleic acids or lipids under different redox conditions and cultivated heterotrophic thermophiles with the genomic potential for macromolecule degradation. We reconstructed 20 metagenome-assembled genomes (MAGs) of uncultured lineages affiliating with known archaeal and bacterial phyla, including endospore-forming Bacilli and candidate phylum Marinisomatota. One Marinisomatota MAG had 35 different glycoside hydrolases often in multiple copies, seven extracellular CAZymes, six polysaccharide lyases, and multiple sugar transporters. This population has the potential to degrade a broad spectrum of polysaccharides including chitin, cellulose, pectin, alginate, chondroitin, and carrageenan. We also describe thermophiles affiliating with the genera Thermosyntropha, Thermovirga, and Kosmotoga with the capability to make a living on nucleic acids, lipids, or multiple macromolecule classes, respectively. Several populations seemed to lack extracellular enzyme machinery and thus likely scavenged oligo- or monomers (e.g., MAGs affiliating with Archaeoglobus) or metabolic products like hydrogen (e.g., MAGs affiliating with Thermodesulfobacterium or Desulforudaceae). The growth of methanogens or the production of methane was not observed in any condition, indicating that the tested macromolecules are not degraded into substrates for methanogenesis in hydrothermal sediments. We provide new insights into the niches, and genomes of microorganisms that actively degrade abundant necromass macromolecules under oxic, sulfate-reducing, and fermentative thermophilic conditions. These findings improve our understanding of the carbon flow across trophic levels and indicate how primary produced biomass sustains complex and productive ecosystems.

Description: We are grateful to the captain and crew of the R/V Atlantis AT37-06 as well as the crew of the human occupied vehicle Alvin for their tireless support. Sampling at Guaymas Basin was supported by NSF (OCE-1357238).

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bayer, B., Saito, M. A., McIlvin, M. R., Lucker, S., Moran, D. M., Lankiewicz, T. S., Dupont, C. L., & Santoro, A. E. (2020). Metabolic versatility of the nitrite-oxidizing bacterium Nitrospira marina and its proteomic response to oxygen-limited conditions. Isme Journal, doi:10.1038/s41396-020-00828-3.

Description: The genus Nitrospira is the most widespread group of nitrite-oxidizing bacteria and thrives in diverse natural and engineered ecosystems. Nitrospira marina Nb-295T was isolated from the ocean over 30 years ago; however, its genome has not yet been analyzed. Here, we investigated the metabolic potential of N. marina based on its complete genome sequence and performed physiological experiments to test genome-derived hypotheses. Our data confirm that N. marina benefits from additions of undefined organic carbon substrates, has adaptations to resist oxidative, osmotic, and UV light-induced stress and low dissolved pCO2, and requires exogenous vitamin B12. In addition, N. marina is able to grow chemoorganotrophically on formate, and is thus not an obligate chemolithoautotroph. We further investigated the proteomic response of N. marina to low (∼5.6 µM) O2 concentrations. The abundance of a potentially more efficient CO2-fixing pyruvate:ferredoxin oxidoreductase (POR) complex and a high-affinity cbb3-type terminal oxidase increased under O2 limitation, suggesting a role in sustaining nitrite oxidation-driven autotrophy. This putatively more O2-sensitive POR complex might be protected from oxidative damage by Cu/Zn-binding superoxide dismutase, which also increased in abundance under low O2 conditions. Furthermore, the upregulation of proteins involved in alternative energy metabolisms, including Group 3b [NiFe] hydrogenase and formate dehydrogenase, indicate a high metabolic versatility to survive conditions unfavorable for aerobic nitrite oxidation. In summary, the genome and proteome of the first marine Nitrospira isolate identifies adaptations to life in the oxic ocean and provides insights into the metabolic diversity and niche differentiation of NOB in marine environments.

Description: We thank John B. Waterbury and Frederica Valois for providing the culture of Nitrospira marina Nb-295T and for continued advice about cultivation. The N. marina genome was sequenced as part of US Department of Energy Joint Genome Institute Community Sequencing Project 1337 to CLD, AES, and MAS in collaboration with the user community. We thank Claus Pelikan for bioinformatic assistance. This research was supported by a Simons Foundation Early Career Investigator in Marine Microbiology and Evolution Award (345889) and US National Science Foundation (NSF) award OCE-1924512 to AES. Proteomics analysis was supported by NSF awards OCE-1924554 and OCE-1850719, and NIH award R01GM135709 to MAS. BB was supported by the Austrian Science Fund (FWF) Project Number: J4426-B (“The influence of nitrifiers on the oceanic carbon cycle”), SL by the Netherlands Organization for Scientific Research (NWO) grant 016.Vidi.189.050, and CLD by NSF award OCE-125999.