ALBERT

Description: The compositional record of the AND-2A drillcore is examined using petrological, sedimentological, volcanological and geochemical analysis of clasts, sediments and pore waters. Preliminary investigations of basement clasts (granitoids and metasediments) indicate both local and distal sources corresponding to variable ice-volume and ice-flow directions. Low abundance of sedimentary clasts (e.g., arkose, litharenite) suggests reduced contributions from sedimentary covers while intraclasts (e.g., diamictite, conglomerate) attest to intrabasinal reworking. Volcanic material includes pyroclasts (e.g., pumice, scoria), sediments and lava. Primary and reworked tephra layers occur within the Early Miocene interval (1093 to 640 metres below sea floor). The compositions of volcanic clasts reveal a diversity of alkaline types derived from the McMurdo Volcanic Group. Finer-grained sediments (e.g., sandstone, siltstone) show increases in biogenic silica and volcanic glass from 230 to 780 mbsf and higher proportions of terrigenous material ca. 350 to 750 mbsf and below 970 mbsf. Basement clast assemblages suggest a dominant provenance from the Skelton Glacier - Darwin Glacier area and from the Ferrar Glacier - Koettlitz Glacier area. Provenance of sand grains is consistent with clast sources. Thirteen Geochemical Units are established based on compositional trends derived from continuous XRF scanning. High values of Fe and Ti indicate terrigenous and volcanic sources, whereas high Ca values signify either biogenic or diagenic sources. Highly alkaline and saline pore waters were produced by chemical exchange with glass at moderately elevated temperatures.

Description: Published

Description: 147-192

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

Description: N/A or not JCR

Description: open

Description: In this paper, we report new GPS measurements which indicate active NE-SW extension and strain accumulation in the Molise region (Apennines, Italy). The GPS observations were collected during campaigns on benchmarks of the dense IGM95 network (average distance 20 km), spanning a maximum observation interval of 13 years, and have been integrated with measurements from the available permanent GPS sites. Considering the differential motion of the GPS sites, located on the Tyrrhenian and Adriatic coasts, we can evaluate a 4-5 mm/yr extension accommodated across this part of the Apennines. The velocity field exhibits clusters of sites with homogeneous velocity vectors, outlining two main divergence areas, both characterized by the largest velocity gradients: one near Venafro and the other near Isernia where two primary active faults and several historical earthquakes have been documented. These results suggest that an active extension in this part of the Apennines can be currently distributed between the two faults systems associated with the largest earthquakes of this region.

Description: Published

Description: 145-156

Description: 3.2. Tettonica attiva

Description: N/A or not JCR

Description: open

Description: Il complesso assetto geomorfologico della Calabria e le sue peculiarità climatiche, tra cui una piovosità maggiore della media nazionale, fanno si che questa sia una delle regioni maggiormente esposte a fenomenologie di dissesto idrogeologico. Quale effetto indiretto della rude morfologia regionale e dello sviluppo territoriale oblungo, il reticolo stradale principale ha un basso grado di interconnessione, circostanza questa che ne amplifica l’intrinseca vulnerabilità. In tale contesto, l’incidenza delle vie di comunicazione veloci e ad elevata capacità è trascurabile, mentre le tipologie costruttive risultano essere, come discusso da questo contributo, non adeguate alla diffusa vulnerabilità idrogeologica del territorio. Piogge intense e/o prolungate determinano la frequente insorgenza di crisi territoriali, comunemente definite eventi alluvionali, che determinano sia frane diffuse che catastrofiche piene, e causano perdite di vite umane nonchè gravi e duraturi danni alle infrastrutture di trasporto. In tali circostanze, i dissesti che si determinano lungo la rete viaria rappresentano una fonte di danno sia diretto che indiretto per la comunità e nei casi più gravi costituiscono un impedimento alle attività di protezione civile. L’analisi sistematica delle tipologie di dissesti che hanno interessato la rete viaria in un arco temporale sufficientemente esteso (80 anni), selezionato per la sua significatività, costituisce uno strumento per la valutazione delle relazioni causa effetto fra il verificarsi di piene ed eventi alluvionali da una parte e l’insorgenza dei dissesti della rete viaria dall’altra. La ricerca si propone di individuare indicazioni utili alla programmazione della manutenzione ordinaria e nonché alla gerarchizzazione delle priorità degli interventi volti a minimizzare i danni causati dalle piene alle infrastrutture lineari di trasporto.

Description: Published

Description: Roma

Description: open

Description: This paper presents a velocity model of the Italian (central Mediterranean) lithosphere in unprecedented detail. The model is derived by inverting a set of 166,000 Pg and Pn seismic wave arrival times, restricted to the highest-quality data available. The tomographic images reveal the geometry of the subduction-collision system between the European, Adriatic, and Tyrrhenian plates, over a larger volume and with finer resolution than previous studies. We find two arcs of low-Vp anomalies running along the Alps and the Apennines, describing the collision zones of underthrusting continental lithospheres. Our results suggest that in the Apennines, a significant portion of the crust has been subducted below the mountain belt. From the velocity model we can also infer thermal softening of the crustal wedge above the subducting Adriatic plate. In the Tyrrhenian back-arc region, strong and extensive low-Vp anomalies depict upwelling asthenospheric material. The tomographic images also allow us to trace the boundary between the Adriatic and the Tyrrhenian plates at Moho depth, revealing some tears in the Adriatic-Ionian subducting lithosphere. The complex lithospheric structure described by this study is the result of a long evolution; the heterogeneities of continental margins, lithospheric underthrusting, and plate indentation have led to subduction variations, slab tears, and asthenospheric upwelling at the present day. The high-resolution model provided here greatly improves our understanding of the central Mediterranean’s structural puzzle. The results of this study can also shed light on the evolution of other regions experiencing both oceanic and continental subduction.

Description: Published

Description: B05305

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: JCR Journal

Description: open

Description: In the previous S6 Project (2004-2007 DPC-INGV Framework Program) a monograph was carried out, that was drawn up for many stations, that were part of the former ENEL accelerometric network. In these monographs all the ENEL documentation about geological information as well as geognostic and geophysical data was included. Knowledge of geological and geomorphological context, and the mechanical and dynamic characteristics of the stations subsoil is fundamental for studies on the attenuation laws and the selection of accelerograms to be used as a seismic input for dynamic analyses for which a classification of the stations subsoil according to the EC8 and national code provisions is necessary. Considering the huge number of sites (over 600), this knowledge have to be rationalized and homogenized so as to arrive at a common and comparable level of information. The station monograph carried out within the past S6 INGV Project had tried to fill the gap in the knowledge of the recording station characteristics, with the advantage of providing a first screening on the quantity and quality of available data; however the collected data included in the monograph turned out to be uneven and incomplete since a robust standard for the collection, homogenization, representation and synthesis of data was not provided. Moreover, expert judgment for assessing quality of data, especially those derived from geotechnical and geophysical tests, was not taken into consideration. This problem has been addressed by Task 2, which has produced a new standard monograph for the ITACA stations. The new release of the station monograph is the first product of the 5 S4 Project (deliverable D3) and can be downloaded from the project website (http://esse4.mi.ingv.it). The new ITACA monograph provides a minimum level of information, homogeneous for all station sites, including multi-disciplinary data to satisfy the needs of different users and duly considers information previously not included. In detail, the new ITACA monograph consists in the following 12 cognitive modules, and various sub-modules.

Description: Progetto DPC-INGV S4 "Banca dati accelerometrica" - Task 2

Description: Published

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: L’evento sismico del 6 aprile 2009 è stato registrato da 57 stazioni accelerometriche delle RAN (Rete Accelerometrica Nazionale, gestita dal Dipartimento della Protezione Civile), alcune delle quali ubicate nella città di L’Aquila (stazione AQK) o nella porzione della Valle dell’Aterno a NW della città (AQA, AQF, AQG, AQM, AQP, AQV). Uno degli obiettivi del Progetto S4, finanziato nell’ambito della Convenzione 2007‐ 2009 tra l’Istituto Nazionale di Geofisica e il Dipartimento della Protezione Civile, consiste nella classificazione dei siti di ubicazione delle postazioni accelerometriche utilizzando le categorie di sottosuolo previste nell’EC8‐NTC2008. Nell’ambito del Task 2 è stata rilasciata una versione preliminare di tale classificazione (vers. 1.0), ottenuta soltanto su base litologica, utilizzando una mappa prodotta dall’INGV in un precedente progetto sismologico (Progetto S6 della Convenzione DPC‐INGV 2005‐ 2007). Questa mappa litologica deriva dalla Carta Geologica d’Italia in scala 1:100.000, mediante l’accorpamento in classi delle Formazioni Geologiche secondo un criterio litologico e di età del deposito. Alle varie classi litologiche ottenute è stata quindi attribuita una delle cinque categorie di sottosuolo (A, B, C, D, E) dell’EC8‐ NTC2008. Per le stazioni per le quali sono disponibili i profili di velocità delle onde di taglio VS, la categoria di sottosuolo è stata eventualmente corretta, scegliendo la classificazione ottenuta dal profilo di velocità delle onde di taglio nei primi 30 metri. Nei giorni successivi all’evento del 6 aprile 2009, i ricercatori dell’UR2 e dell’UR6 del Progetto S4, impegnati nel Task 2, hanno effettuato sopralluoghi finalizzati alla verifica della localizzazione geografica, delle condizioni morfologiche e geologiche locali di alcune stazioni di registrazione ubicate nell’area aquilana. Sulla base delle informazioni raccolte e dei dati acquisiti, è stata prodotta una versione aggiornata (vers. 1.1) della classificazione di sito per le suddette stazioni, attualmente disponibile sul sito web del Progetto S4 (http://esse4.mi.ingv.it).

Description: Progetto DPC-INGV S4: "Banca dati accelerometrica"

Description: Published

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: The presence of quarry and mine blasts in seismic catalogues is detected using the Wiemer and Baer (Bull Seism Soc Am 90(2):525–530, 2000) algorithm. The procedure is based on the observation that quarry blasts generally take place during daytime hours: the areas with a high ratio of daytime and night-time events are likely to be regions with quarry activity. In the first part of this work we have tested the method, using both a synthetic and a regional catalogue; in the second part the procedure has been applied to some of the European regional catalogues available on line. The comparison between the results obtained and the location of known quarries and mines for the analysed catalogues confirms the reliability of the methodology in identifying mining areas.

Description: This research was partially supported by the transnational access activity of the European Union project NERIES (contract number 026130)

Description: Published

Description: 229–249

Description: 4IT. Banche dati

Description: JCR Journal

Description: open

Description: The importance of detecting possible electromagnetic signatures due to large earthquakes is self-evident, signatures which can be either anticipating, simultaneous or subsequent with respect to the main shock. Taking advantage of the present low Earth’s orbiting CHAMP satellite, we apply an “ad hoc” technique based on the Information Theory, to the satellite magnetic data with the aim at extracting eventual time anomalies. This technique has small time-space resolution using a preliminary wavelet analysis in order to detect shorter-wavelength anomalies. Some examples are given for magnetic satellite data taken over periods including the times of two large earthquakes, one being the Sumatra region event on 26 December 2004 (M=9.1).

Description: Published

Description: Potsdam, Germany

Description: 1.6. Osservazioni di geomagnetismo

Description: open

Description: Nei mesi successivi al terremoto che ha colpito l’Abruzzo il 6 aprile 2009, varie istituzioni nazionali ed internazionali hanno installato decine di stazioni per monitorare più di 100 località con l'obiettivo di studiare gli effetti di sito nell'area epicentrali (alta e media valle dell’Aterno). Le stazioni sismiche (accelerometri e velocimetri) sono state collocate nei centri abitati o in prossimità di essi. Tra le aree investigate figura Onna, uno dei paesi maggiormente danneggiati e che ha registrato un elevato numero di vittime, e il centro storico de L’Aquila, dove sono state installate numerose stazioni velocimetriche, in alcuni casi affiancate da accelerometri. I risultati per i siti esaminati mostrano una estrema variabilità della risposta sismica locale, con rilevanti effetti di amplificazione in alcuni dei centri abitati più danneggiati.

Description: Published

Description: 69-73

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: N/A or not JCR

Description: open

Description: In November 2008, the ionosonde station at Boulder, Colorado, USA (40.0°N; 105.3°W) became the host of a new ionosonde (VIPIR, Vertical Incidence Pulsed Ionospheric Radar) developed and built by Scion Associates. The VIPIR is a fully digital frequency agile radar that operates between 0.3 and 26 MHz. It features 8 digital receivers and a digital transmit exciter. Extremely high performance analog receive electronics and a 4 kW solid state amplifier provide interface to the real world. This work describes the application of Autoscala to the ionograms recorded by this ionosonde. First results, in terms of ionograms and autoscaled characteristics, are presented and discussed.

Description: Published

Description: 1156-1172

Description: 1.7. Osservazioni di alta e media atmosfera

Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale

Description: JCR Journal

Description: reserved

Description: BREVIA

Description: We report on the discovery in southern Egypt of an impact crater 45 m in diameter with a pristine rayed structure. Such pristine structures have been previously observed only on atmosphereless rocky or icy planetary bodies in the Solar System. This feature and the association with an iron meteorite impactor and shock metamorphism provides a unique picture of small-scale hypervelocity impacts on the Earth's crust. Contrary to current geophysical models, ground data indicate that iron meteorites with masses of the order of tens of tons can penetrate the atmosphere without significant fragmentation.

Description: Published

Description: 804

Description: 1.8. Osservazioni di geofisica ambientale

Description: 3.8. Geofisica per l'ambiente

Description: JCR Journal

Description: open

Description: Within the scope of the EC-projects NERIES and ITSAK-GR we have applied a procedure able to combine a multi-model space parameterization and an information theoretic approach in analysis of dispersion curve inversion. In detail we considered the dispersion curve assessed at 14 strong motion European sites. At each site we investigated the model space through four different parameterization groups within the wavelength range estimated by actual dispersion curves. In order to explore the influence of model space we increased progressively the number of layers for each parameterization. We therefore addressed the model evaluation among a set of competing models obtained by inversion following the corrected Akaike’s Information Criterion(AICc). By using such information-theoretic approach, we found an acceptable agreement between the inverted shear-velocity profiles of the best models and the available borehole results.

Description: IZIIS

Description: Published

Description: Ohrid, Republic of Macedonia

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: Hydrological, current-meter and meteorological data were acquired in the northern Ligurian sea in summer 2004. Data have been collected using different kind of instruments and resolutions. This work merges different sources of data to describe the coastal dynamic around the Cape of Portofino and to define its relation with the general cyclonic circulation in the area (represented by Arenzano current), the orography and the meteorological forcing.

Description: Unpublished

Description: Villa Marigola, Lerici, Italy

Description: 3.7. Dinamica del clima e dell'oceano

Description: restricted

Description: On 6 April 2009, a magnitude Mw = 6.1 earthquake struck the Abruzzi region in central Italy. Despite its moderate size, the earthquake caused more than 300 fatalities and partially destroyed the city of L’Aquila and many surrounding villages. In this study we present a retrospective analysis of the rapid source parameters determination procedure developed at INGV (Scognamiglio et al. 2009) as applied to the L’Aquila seismic sequence. Our approach consists of two stages: the near real-time determination of the seismic moment tensor, which is already routinely performed for all M≥ 3.5 earthquakes; and the rapid imaging of the rupture history on a finite fault for earthquakes with M≥ 6.0.

Description: Published

Description: 892-906

Description: 3.1. Fisica dei terremoti

Description: JCR Journal

Description: reserved

Description: In the framework of the EU-NERIES project, 20 sites among all European strong motion sites in Italy, Greece, T urkey and France were selected to be representative of most common soil classes, and for which shear-wave velocities from borehole measurements (cross-hole and down-hole tests) are available. Passive (array noise) and active experiments have been carried out at these sites in order to evaluate the ability of surface waves technique to provide reliable estimates of shear-wave velocity profiles. In order to stay cheap and feasible, active seismic experiments involving 24 geophones and hammer source were carried out at all sites. Data were processed by using the MASW technique and Rayleigh and Love waves dispersion curves were retrieved from 5-10 Hz to 30-50 Hz. Passive array experiments were also performed by using 8 seismological stations linked with wireless connections and monitored with near real-time processing. Combining up to four different arrays with aperture ranging from 10 m and to 900 m, Rayleigh and Love waves dispersion curves were derived over a broad frequency range (from 0.5 Hz up to 45 Hz) by using the FK and MSPAC techniques. At about 75% sites, dispersion curves from ambient vibration and MASW are in good agreement over the overlapping frequency band. T he other 25% sites correspond to complex geometrical site structures. Whatever the site, passive experiments are shown to be very suitable to retrieve accurate estimates of phase velocities at high frequency (over 20-30 Hz). T his experiment also clearly outlined the limited penetration depth (comprised between 15 and 25 m) of the MASW technique. Inversion of dispersion curves to derive shear-wave profiles and EC8 site class (which is mainly based on Vs30) is a difficult and highly debated issue. Here we test an alternative to get average shear-wave profiles and especially Vs30 from the dispersion curves only. For these 20 sites, we show that site classes may be estimated directly from the dispersion curves. T heses results are confirmed by an extensive study involving about 800 velocity profiles from real sites.

Description: Published

Description: Montpellier, France

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: The Colli Albani is a quiescent volcano located nearby the city of Roma, characterised by the presence of an active geothermal system, periodic seismic swarms and intense diffuse degassing. Several accidents, some of which lethal, have occurred in recent years associated to episodes of more intense releases and outbursts of volcanic gases, dominantly CO2 and H2S. Gas emissions are presently the most hazardous phenomenon for the highly populated Colli Albani area, along with the potential occurrence of seismic activity. This chapter presents the numerical modeling of heat and fluid circulation applied to study the mechanisms which control the diffuse degassing at Colli Albani volcano. Multi-phase and multi-component simulations were carried out using the TOUGH2 geothermal simulator in a realistic geological context, which includes all available information on the stratigraphy and structure of the Colli Albani substrate, along with data on the total gas flux, the local geothermal gradient, the local hydrogeology, and the thermal characteristics of the rocks. The geothermal reservoir at Colli Albani is hosted by the 2-3000 m thick Mesozoic-Cenozoic carbonatic succession capped by Pliocene clays which act as aquiclude and are few hundreds to over 1000m thick, in turned covered by continental sedimentary and volcanic deposits, which host the shallow hydrogeological system. Numerical simulations evaluate the effects associated with the thickness of the carbonatic basement and its cap rock; the role of CO2 supply rate at depth; and the influence of permeable channelways through the cap rocks. Numerical simulations show that thickness of the geothermal reservoir hosted by the carbonatic basement and of its impervious cover control the vigor of the convection, the extent and depth (and hence temperature) of the lateral recharge area, and the distribution of the carbon dioxide within the system. This result suggests that the temperature distribution and diffuse degassing at surface do not simply reflect the characteristics of the heat and fluid source at depth, but also the specific structure and hydrological properties of the site where they are measured.

Description: Submitted

Description: 311-329

Description: 4V. Processi pre-eruttivi

Description: open

Description: We describe the setting up of the first earthquake forecasting experiment for Italy within the Collaboratory for the Study of Earthquake Predictability (CSEP). CSEP conducts rigorous and truly prospective forecast experiments for different tectonic environments in several forecast testing centers around the globe; forecasts are issued for a future period and also tested only against future observations to avoid any possible bias. As such, experiments need to be completely defined. This includes exact definitions of the testing area, of learning data for the forecast models, and of observation data against which forecasts will be tested to evaluate their performance. Here we present the rules, as taken from the Regional Earthquake Likelihood Models experiment and extended or changed for the Italian experiment. We also present characterizations of learning and observational catalogs that describe the completeness of these catalogs and illuminate inhomogeneities of magnitudes between these catalogs. A particular focus lies on the stability of earthquake recordings of the observational network. These catalog investigations provide guidance for CSEP modelers for developing earthquakes forecasts for submission to the forecast experiment in Italy.

Description: Published

Description: 1-9

Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale

Description: 5.1. TTC - Banche dati e metodi macrosismici

Description: 5.2. TTC - Banche dati di sismologia strumentale

Description: JCR Journal

Description: open

Description: Negli ultimi 5 anni si è assistito ad un rapido aumento del numero di reti di stazioni GPS continue (CGPS) attive sul territorio Italiano e, più in generale, nell’area Mediterranea. Se da un lato lo sviluppo delle reti CGPS per lo studio dei fenomeni geofisici (terremoti, vulcani, variazioni del livello del mare, ecc...) è ancora legato a particolari programmi di ricerca nei diversi paesi del bacino Mediterraneo, dall’altro un po’ in tutta Europa, ma anche in alcune aree del continente Africano, si è assistito alla nascita di reti CGPS realizzate per scopi diversi da quelli geofisici (cartografici, topografici, catastali o per la navigazione). Se da una parte le reti CGPS realizzate con criteri “geofisici” [es., Anzidei & Esposito, 2003] forniscono un dato generalmente più affidabile, in termini di stabilità delle monumentazioni, qualità del dati e continuità temporale delle osservazioni, dall’altra le reti CGPS regionali di tipo “non-geofisico”, nonostante una distribuzione ovviamente disomogenea, hanno dimostrato di fornire comunque informazioni utili alla stima dei campi di velocità e di deformazione crostale [es., D’Agostino et al., 2008], e di integrarsi il più delle colte con altre reti di tipo “geofisico” esistenti. Al fine di migliorare la risoluzione spaziale del segnale tettonico misurabile da una rete GPS, la scelta di realizzare un computer cluster per l’analisi dati GPS è stata presa al fine di garantire un rapido, ed il più possibile automatico, processamento di tutti i dati a disposizione per l’area Euro-Mediterranea ed Africana. I software comunemente utilizzati in ambito scientifico per l’analisi dei dati GPS sono il GAMIT/GLOBK il BERNESE ed il GIPSY. Al di là delle differenze legate agli algoritmi di calcolo dei tre software in questione, e dei vantaggi o svantaggi di uno e dell’altro approccio di cui necessitano, una corretta progettazione della dotazione hardware e software è il passaggio fondamentale per la creazione di un moderno ed efficiente centro di analisi dati GPS finalizzato alla razionalizzazione delle risorse e dei costi. Dato il numero molto elevato di stazioni CGPS oggi potenzialmente disponibili (diverse centinaia per la sola area Mediterranea), una procedura che analizzi simultaneamente tutte le stazioni è difficilmente praticabile. Nonostante recenti sviluppi di nuovi algoritmi [Blewitt, 2008] rendano effettivamente possibile un’analisi simultanea di “mega-reti”, anche a scala globale, la disponibilità di calcolo su sistemi multi- processore risulta comunque fondamentale. Nel caso specifico in cui il software utilizzato per l’analisi dei dati si basi su soluzioni di rete (network solutions), come il BERNESE ed il GAMIT, riveste fondamentale importanza lo sfruttamento ottimale delle risorse computazionali, e soprattutto la possibilità di sfruttare appieno le potenzialità sia dei più recenti computer multi-processore che dei nuovi processori ad architettura multi-core. Nessuno dei software indicati precedentemente è implementato per il calcolo parallelo, di conseguenza, lo sfruttamento delle architetture multi-processore o multi-core deve passare necessariamente per altre vie. Una di queste è quella del calcolo distribuito (distributed-processing), in cui, ad esempio, diversi nodi di calcolo (che possono essere diverse macchine, diversi processori, o diversi core di processori) analizzano reti CGPS diverse, o diversi giorni della stessa rete CGPS. Se da una parte il mercato offre numerose soluzioni commerciali per la realizzazione di procedure di calcolo distribuito (Microsoft Windows Compute Cluster Server 2003, Sun Cluster, NEC ExpressCluster; IBM Parallel Sysplex, per citarne alcuni), dall’altra la disponibilità di software open source per questo tipo di scopi è oggi completa e ben integrata nei sistemi operativi UNIX based.   In questo rapporto tecnico viene descritta la procedura seguita per la realizzazione di un nuovo server per l’analisi dei dati GPS presso la Sede INGV di Bologna basato su un computer cluster, utilizzando software Open Source, in ambiente GNU/Linux.

Description: INGV

Description: Published

Description: 1.9. Rete GPS nazionale

Description: open

Description: Continuous marine successions covering the Middle Miocene Climate Transition (MMCT; ∼15–13.7 Ma) are scarce and the lack of a high-resolution magnetobiostratigraphic framework hampers the construction of astronomically tuned age models for this time interval. The La Vedova High Cliff section, exposed along the coast of the Cònero Riviera near Ancona (Italy), is one of the few Mediterranean sections covering the critical time interval of the MMCT. Starting from an initial magnetobiostratigraphic age model, a robust astronomical tuning was constructed for the interval between 14.2 and 13.5 Ma, using geochemical element data and time series analysis. A shift in δ18O of bulk sediment towards heavier values occurs between ∼13.92 and 13.78 Ma and could be related to the Mi3b oxygen isotope event, which reflects the rapid expansion of the East Antarctic Ice Sheet in the middle Miocene. The onset of the CM6 carbon excursion is reflected in the bulk record by a rapid increase in δ13C at 13.86 Ma. Our results confirm the proposition that these events coincide with a 405-kyr minimum in eccentricity and a node in obliquity related to the ∼1.2 Myr cycle. From 13.8 Ma onwards, distinct quadruplet cycles containing sapropelitic sediments were deposited. This may suggest a causal connection between the main middle Miocene cooling step and the onset of sapropel formation in the Mediterranean.

Description: Published

Description: 249–261

Description: 2.2. Laboratorio di paleomagnetismo

Description: JCR Journal

Description: restricted

Description: Vengono presentati i risultati preliminari della campagna oceanografica CAFE_07 - Leg 3, svoltasi nei Golfi di Napoli e Pozzuoli, nel Gennaio 2008, a bordo della Nave Oceanografica (N/O) URANIA del CNR. Lo scopo della campagna è stato l’acquisizione di profili sismici multicanale di elevata risoluzione dedicati allo studio stratigrafico-strutturale degli apparati vulcanici affioranti e sepolti nell’offshore Napoletano, ed il rilievo batimetrico di dettaglio dell’area sommersa. I dati raccolti sono consistiti in circa 800 km di profili sismici a riflessione multicanale di alta risoluzione, con acquisizione sismica simultanea da due sorgenti GI-gun operanti con potenza e frequenze differenti,mediante due cavi idrofonici. Durante la navigazione sono stati anche acquisiti profili sismici a riflessione monocanale di altissima risoluzione (sub-bottom CHIRP) e dati batimetrici mediante ecoscandaglio multifascio (multibeam). Il grid di acquisizione sismica multicanale è consistito in alcuni profili lunghi attraverso il Golfo di Napoli e da una fitta griglia di profili più corti, con interasse di circa 150 m, allo scopo di ottenere una copertura sismica quasi 3-D del Golfo di Pozzuoli. Questo set di dati costituisce una parte delle indagini di dettaglio richieste per la stesura di una proposta di perforazione del settore sommerso dei Campi Flegrei da sottomettere all’Integrated Ocean Drilling Program (IODP) ed è di supporto alla realizzazione di un progetto di perforazione profonda dei Campi Flegrei presentato all’International Continental Drilling Program (ICDP). We present the preliminary results of the oceanographic cruise CAFE_07 – Leg 3, conducted in the Napoli and Pozzuoli Bays in January 2008, on board of the Research Vessel (R/V) URANIA of the CNR. The aim of the cruise was the acquisition of high resolution multi-channel seismic profiles to understand the stratigraphic-structural setting of the Pozzuoli Bay area, with specific reference to the major offshore volcanic features, as well as the acquisition of bathymetric data on the seafloor morphology of the Bay. About 800 km of seismic profiles were acquired simultaneously by two acquisition systems, each characterized by different seismic source and streamer configuration, operating at different frequency ranges. Moreover shallow high resolution seismic reflection profiles (sub-bottom CHIRP) and multibeam echo-sounder bathymetry data have been recorded. The seismic grid consisted in a number of assistant profiles acquired over the Bay of Naples, along with a dense network of profiles with average distance of about 150 m between navigation routes, in order to obtain a quasi 3-D seismic coverage of the Pozzuoli Bay. This data set represents a part of the requirements for on-site detailed investigations (“site survey”) that are necessary for the development of an Integrated Ocean Drilling Program (IODP) proposal dedicated to the offshore drilling of the Campi Flegrei and is a relevant complement in the site survey of an ongoing project that has been submitted to the International Continental Drilling Program (ICDP).

Description: INGV Istituto Nazionale di Geofisica e Vulcanologia

Description: Published

Description: 5-23

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: N/A or not JCR

Description: open

Description: The macroseismic surveys of earthquakes occurred in Sicily during the time-span 2006-2008, are hereinafter presented. Analysed data mainly concern events located in the volcanic region of Mt. Etna, together with other regional shocks which have produced relevant macroseismic effects in northern and southern Sicily. Data have been collected following the guidelines of the QUEST working group (QUick Earthquake Survey Team, and then processed according to the procedures used for compiling the catalogue and macroseismic database issued in the framework of the TTC (Transversely Coordinated Theme) 5.1 “Banche dati e metodi macrosismici” of INGV.

Description: Published

Description: 1-37

Description: 5.1. TTC - Banche dati e metodi macrosismici

Description: N/A or not JCR

Description: open

Description: The 1974 western flank eruption of Mount Etna produced a rare, nearly aphyric and plagioclase-free trachybasalt that could not be derived from the central volcano conduits and was more alkaline and more radiogenic than all previous historical lavas. New results for the petrochemistry and volatile content of its products, combined with contemporaneous seismic and volcanological observations, allow us to reinterpret the origin and significance of this event. We show that the eruption was most likely triggered by deep tectonic fracturing that allowed a dike-like intrusion to propagate in 9 days from 11 km depth up to the surface, bypassing the central conduits. Relatively fast, closed system decompression of the volatile-rich magma initially led to lava fountaining and the rapid growth of two pyroclastic cones (Mounts De Fiore), followed by Strombolian activity and the extrusion of viscous lava flows when gas-melt separation developed in the upper portion of the feeding fracture. The 1974 trachybasalt geochemistry indicates its derivation by mixing 25% of preexisting K-poor magma (best represented by 1763 La Montagnola eruption’s products) and 75% of a new K-rich feeding magma that was gradually invading Mount Etna’s plumbing system and became directly extruded during two violent flank eruptions in 2001–2003. We propose to classify 1974-type so-called ‘‘eccentric’’ eruptions on Etna as deep dike-fed (DDF) eruptions, as opposed to more common central conduit-fed flank eruptions, in order to highlight their actual origin rather than their topographic location. We ultimately discuss the possible precursors of such DDF eruptions.

Description: Published

Description: B07204

Description: 3.6. Fisica del vulcanismo

Description: JCR Journal

Description: reserved

Description: The rapid urban development in Istanbul has lead to an increase in the exposure levels of the urban vulnerability. Due to the steadily increasing population, with improper land-use planning, inappropriate construction techniques and inadequate infrastructure systems, associated with an existing high hazard level, Istanbul is one of the most risky cities in the Mediterranean region. Estimations of casualties and losses, expected for given earthquake scenarios, are necessary to develop sustainable rehabilitation programs and for improving preparedness. Deterministic hazard scenarios and time-dependent probabilistic hazard assessment were used as input to a GIS-based loss estimation model, to evaluate the earthquake risk for Istanbul. The deterministic ground shaking scenarios, used for loss estimation in Istanbul, were defined in terms of acceleration and velocity time series for recognized reference earthquakes caused by different rupture models along extended sources. The ground motions were calculated for the whole metropolitan area extending over a grid system of 25×100 km2. For the case of Istanbul, the representative scenario was selected by comparing the simulated peak values and response spectra with the empirical ground motion models available for the area. Simulated values are within one standard deviation of the empirical regressions. The availability of wide-ranging building inventory data allowed the application of a GIS-based loss estimation model (KoeriLoss-V2) to evaluate different loss scenarios depending on the ground shaking input, as well as to consider the implications of mitigation actions. It was found that 30% of the buildings in the metropolitan area may be in need of either strengthening or demolition to achieve an adequate degree of life safety.

Description: Published

Description: 699-709

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: JCR Journal

Description: reserved

Description: We report results from a multidisciplinary campaign carried out at Poás crater-lake (Costa Rica) on 17-18 March 2009. Thermal imagery of fumaroles on the north side of the dome and the lake surface revealed mean apparent temperatures of 25-40°C (maximum of 80°C), and 30-35°C (maximum of 48°C), respectively. Mean radiative heat output of the lake, uncorrected for downwelling flux, was estimated as ~230 MW. The mean SO2 flux emitted by the crater measured by walking-traverses was 76 tonnes day-1, with approximately equal contributions from both the dome and the lake and fumarole plumes. Gas measurements by active open-path FTIR spectroscopy indicated molar ratios of H2O/SO2 = 151 and CO2/SO2 = 1.56. HCl and HF were not detected in measured spectra but based on the detection limits of these species, we calculate SO2/HCl 〉 40, and SO2/HF 〉 200. Particles were sampled from the plume by air filtration. The filters were analysed using ion chromatography, which revealed an abundance of K+ and SO42-, with smaller amounts of Ca2+, Mg2+ and Cl-. We discuss here the implications of the results for degassing pathways through the shallow magmatic-hydrothermal system.

Description: Published

Description: San Francisco, USA

Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani

Description: open

Description: Questa ricerca, condotta nell’ambito del Progetto RELUIS – Linea 10, ha riguardato la messa a punto di un modello di rischio sismico per Sistemi Urbani con approccio multilivello, utilizzando l’analogia con le reti neuronali. Il primo passo è stata l’elaborazione del livello 0, basato su banche-dati, disponibili a livello nazionale, relative alla pericolosità sismica di base e locale (INGV) e a dati di censimento dei comuni italiani (ANCITEL 2001; ISTAT 2001) per la descrizione fisica e funzionale dei centri abitati/sistemi urbani analizzati. Per semplicità e per omogeneità tra i molti dati elaborati sono stati trascurati due aspetti rilevanti per il modello di rete neuronale, che intervengono invece ai livelli successivi, ovvero l’aspetto della “soglia” di perdita di capacità di una componente di sottosistema (sia per evoluzione che per connessione) e l’aspetto della “capacità iniziale” di una componente di sottosistema prima dell’evento sismico. La valutazione della perdita di capacità complessiva di un Sistema Urbano a livello 0 è stata quindi calcolata come l’insieme delle perdite di tutti i sistemi combinati tra loro (con opportuni pesi) e quindi con un valore complessivo.

Description: Published

Description: Bologna

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: open

Description: Analyzing ocean variability, understanding its importance for the climate system, and quantifying its socio-economic impacts are among the primary motivations for obtaining ongoing global ocean observations. There are several possible approaches to address these tasks. One with much potential for future ocean information services and for climate predictions is called ocean synthesis, and is concerned with merging all available ocean observations with the dynamics embedded in an ocean circulation model to obtain estimates of the changing ocean that are more accurate than either system alone can provide. The field of ocean synthesis has matured over the last decade. Several global ocean syntheses exist today and can be used to investigate key scientific questions, such as changes in sea level, heat content, or transports. This CWP summarizes climate variability as “seen” by several ocean syntheses, describes similarities and differences in these solutions and uses results to highlight developments necessary over the next decade to improve ocean products and services. It appears that multi-model ensemble approaches can be useful to obtain better estimates of the ocean. To make full use of such a system, though, one needs detailed error information not only about data and models, but also about the estimated states. Results show that estimates tend to cluster around methodologies and therefore are not necessarily independent from each other. Results also reveal the impact of a historically under-sampled ocean on estimates of inter-decadal variability in the ocean. To improve future estimates, we need not only to sustain the existing observing system but to extend it to include full-depth ARGO-type measurements, enhanced information about boundary currents and transports through key regions, and to keep all important satellite sensors flying indefinitely, including altimetry, gravimetry and ice thickness, microwave SST observations, wind stress measurements and ocean color. We also need to maintain ocean state estimation as an integral part of the ocean observing and information system.

Description: Published

Description: Venice, Italy

Description: 3.7. Dinamica del clima e dell'oceano

Description: open

Description: Monthly averaged total volume transport of the Indonesian throughflow (ITF) estimated by 14 global ocean data assimilation (ODA) products that are decade to multi-decade long are compared among themselves and with observations from the INSTANT Program (2004-2006). The ensemble averaged, time-mean value of ODA estimates is 13.6 Sv (1 Sv = 106 m3/s) for the common 1993-2001 period and 13.9 Sv for the 2004-2006 INSTANT Program period. These values are close to the 15-Sv estimate derived from INSTANT observations. All but one ODA time-mean estimate fall within the range of uncertainty of the INSTANT estimate. In terms of temporal variability, the average scatter among different ODA estimates is 1.7 Sv, which is substantially smaller than the magnitude of the temporal variability simulated by the ODA systems. Therefore, the overall “signal-to-noise” ratio for the ensemble estimates is larger than one. The best consistency among the products occurs on seasonal-to-interannual time scales, with generally stronger (weaker) ITF during boreal summer (winter) and during La Nina (El Nino) events. The averaged scatter among different products for seasonal-to-interannual time scales is approximately 1 Sv. Despite the good consistency, systematic difference is found between most ODA products and the INSTANT observations. All but the highest-resolution (18-km) ODA product show a dominant annual cycle while the INSTANT estimate and the 18-km product exhibit a strong semi-annual signal. The coarse resolution is an important factor that limits the level of agreement between ODA and INSTANT estimates. Decadal signals with periods of 10-15 years are seen. The most conspicuous and consistent decadal change is a relatively sharp increase in ITF transport during 1993-2000 associated with the strengthening tropical Pacific trade wind. Most products do not show a weakening ITF after the mid-1970s’ associated with the weakened Pacific trade wind. The scatter of ODA estimates is smaller after than before 1980, reflecting the impact of the enhanced observations after the 1980s. To assess the representativeness of using the average over a three-year period (e.g., the span of the INSTANT Program) to describe longer-term mean, we investigate the temporal variations of the three-year low-pass ODA estimates. The median range of variation is about 3.2 Sv, which is largely due to the increase of ITF transport from 1993 to 2000. However, the three-year average during the 2004-2006 INSTANT Program period is within 0.5 Sv of the long-term mean for the past few decades.

Description: Published

Description: 3.7. Dinamica del clima e dell'oceano

Description: JCR Journal

Description: partially_open

Description: Istituto Nazionale di Geofisica e Vulcanologia; CNR-IGAG, Università degli Studi di Roma TRE, DiMSAT- Università degli Studi di Cassino;

Description: Published

Description: 3.2. Tettonica attiva

Description: open

Description: Il 6 Aprile 2009 un terremoto di Ml=5.8 (Mw=6.2) ha colpito L’Aquila e la media valle dell’Aterno in Abruzzo. In questo lavoro presentiamo in maniera sintetica i rilievi geologici effettuati in campagna dal gruppo di lavoro EmerGeo a seguito della sequenza sismica aquilana. Le attività di rilevamento condotte sono consistite principalmente nella verifica, definizione e caratterizzazione delle deformazioni cosismiche superficiali osservate lungo le strutture tettoniche note in letteratura; sono stati inoltre rilevati e riportati altri effetti cosismici locali (fratture su asfalto, frane e scivolamenti) non direttamente collegati alla presenza di strutture tettoniche. In totale sono stati rilevati oltre 300 punti di osservazione su una porzione di territorio estesa circa 900 km2. L’analisi preliminare dei rilievi effettuati indica che le rotture osservate lungo la faglia di Paganica, per la continuità e le caratteristiche, rappresentano l’espressione superficiale della faglia responsabile dell’evento del 6 aprile 2009, e che le rotture lungo le faglie di Bazzano e di Monticchio-Fossa possono rappresentare l’espressione in superficie di una struttura antitetica riattivata durante l’evento.

Description: Published

Description: 1-79

Description: 3.2. Tettonica attiva

Description: N/A or not JCR

Description: open

Description: Abstract This paper briefly describes the preliminary results of an experimentation aimed to test a new non-destructive methodology based on the integrated application of 3-D terrestrial laser scanning and acoustic techniques in the ultrasonic range (54 kHz) in evaluating the quality of carbonatic stone materials. Our target is to evaluate the state of conservation of stone building materials by correlating ultrasonic longitudinal pulse velocity and frequency spectra of the ultrasonic signals with the reflectivity or reflectance of the reflected 3-D laser scanner beam pulse transmitted to the target of an investigated surface.

Description: Leica Geosystems Italia

Description: Published

Description: 45-56

Description: 1.10. TTC - Telerilevamento

Description: N/A or not JCR

Description: open

Description: Hydrothermal alteration may weaken volcanic rocks, causing the gravitational instability of portions of active volcanoes with potentially hazardous collapses. Here we show high‐resolution multibeam, magnetic and gravity surveys of the Marsili seamount, the largest active volcano of Europe located in the southern Tyrrhenian back‐arc basin. These surveys reveal zones with exceptionally low densities and with vanishing magnetizations, due probably to the comminution of basalts during hyaloclastic submarine eruptions and to their post‐eruptive hydrothermal alteration. The location of these regions correlates with morphological data showing the occurrence of past collapses. Similar evidence has been obtained from pre existing data at Vavilov Seamount, another older volcanic system in the Tyrrhenian back‐arc basin. Here a large volume of at least 50 km3 may have collapsed in a single event from its 40 km long western flank. Given the similarities between these volcanoes, a large collapse event may also be expected at Marsili.

Description: Published

Description: L03305

Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive

Description: 3.4. Geomagnetismo

Description: JCR Journal

Description: reserved

Description: New high-resolution bathymetric and magnetic data from the western Aeolian sector, southern Tyrrhenian Sea, provide insights into structural and volcanic development of the area, suggesting a strong interaction between volcanism and tectonics. The analysis of these data combined with relocated earthquake distribution, focal plane solutions and strain rate evaluation indicates that the dextral strike-slip Sisifo-Alicudi shear zone is a complex and wide area of active deformation, representing the superficial expression of the deep seated lithospheric tear fault separating the subduction slab below Sicily and Calabria. Most of the observed volcanic features are aligned along a NW–SE trend, such as the Filicudi island-Alicudi North Seamount and Eolo-Enarete alignments, and are dissected by hundred-metre-high scarps along conjugate NNE–SSW trending fault systems. The magnetic field pattern matches the main trends of volcanic features. Spectral analysis and Euler deconvolution of magnetic anomalies show the existence of both deep and shallow sources. High-amplitude, high-frequency anomalies due to shallow sources are dominant close to the volcanic edifices of Alicudi and Filicudi, while the main contribution on the surrounding Eolo, Enarete, Alicudi North and Filicudi North seamounts is given by low-amplitude anomalies and/or deeper magnetic sources. This is probably related to different ages of the volcanic rocks, although hydrothermal processes may have played an important role in blanketing magnetic anomalies, in particular at Enarete and Eolo seamounts. Relative chronology of the eruptive centres and the inferred deformation pattern outline the Quaternary evolution of the western Aeolian Arc: Sisifo, Alicudi North and Filicudi North seamounts might have developed in an early stage, following the Late Pliocene–Early Pleistocene SE-ward migration of arc-related volcanism due to the Ionian subduction hinge retreat; Eolo, Enarete and Filicudi represent later manifestations that led volcanoes to develop duringMid-Late Pleistocene, when the stress regime in the area changed, due to the SSE-ward propagation of the subduction slab tear fault and the consequent reorientation and decrease of trench migration velocity. Finally, volcanic activity occurred in a very short time span at Alicudi, where an almost conical volcanic edifice emerged, suggesting negligible interactions with regional fault systems.

Description: Published

Description: 64-78

Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: 3.4. Geomagnetismo

Description: JCR Journal

Description: restricted

Description: The Mediterranean Operational Oceanography Network (MOON ) provides near-real-time information on oil spill detection and predictions that have been used during the Lebanese oil pollution crisis in summer 2006. A MOON decision support system for oil spill monitoring and prediction comprising ocean colour satellite and SAR images, ocean current forecast (MFS-Mediterranean Forecasting System and CYCOFOS-CYprus Coastal Ocean Forecasting & Observing System) and the MEDSLIK oil spill model has been developed. The oil spill predictions obtained with MEDSLIK coupled to the CYCOFOS high-resolution ocean fields are compared with the oil spill predictions obtained using the lower resolution MFS hydrodynamics and both are validated against satellite observations. The predicted beached oil quatity along the Lebanese and Syrian coasts are compared with the in-situ observations. It is found that predictions with both CYCOFOS and MFS ar capable to simulate the northward movement of the oil, with the higher resolution CYCOFOS predictions in better agreement with satellite observations. Among the free MEDSLIK oil spill parameters tested in the sensitivity experiments there are the wind corrections (wind factor and angle) and the depth of coupling between eulerian fields and wind correction. Among them the drift factor appeared the most relevant in order to improve the quality of results suggesting that operational models such as MFS and CYCOFOS still lack of enought resolution and physical process at the air-sea interface. The oil moved from Lat 33°40'N Lon 35°24.75'E northward toward Syria, which was reached in 10 days at Lat 34° 38.451'N Lon 35° 58.377'E; the oil movement is followed up to August 6 when the oil reached 35.5°N.

Description: Not submitted

Description: 4.6. Oceanografia operativa per la valutazione dei rischi in aree marine

Description: JCR Journal

Description: open

Description: The paper reports the comparison between 1D, 2D and 3D numerical simulations of seismic site response at San Giuliano di Puglia (Italy) and the amplification recorded in the aftershocks following the 31.X.2002 Molise earthquake (MW=5.7). The records were taken by mobile stations installed in the historical center on a soft rock outcrop and in the newer part of the town on a marly clay formation. The site response analyses by the 3D model involved a subsoil volume of about a 2000 x 2000 x 1500 m, including the extension of the whole town center at surface. 2D site response analyses were carried out on a section developing along the longitudinal axis of the town, and 1D simulations were referred to the subsoil profiles at the seismic stations. 1D and 2D models accounted for the heterogeneity of clayey formation, along both vertical and horizontal directions, as evidenced by a comprehensive geotechnical investigation. The results of numerical predictions are compared to the aftershocks records in terms of amplification functions and ground motion parameters (peak acceleration and Housner intensity).

Description: Published

Description: 62-71

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: N/A or not JCR

Description: open

Description: We applied the method for Probabilistic Tsunami Hazard Analysis (PTHA), first introduced by Rikitake and Aida (1988), to the coasts of eastern Sicily (Italy), and focusing on important cities such as Messina, Catania, and Augusta. The method has been very recently improved by Gonzàlez et al. (2009) to explicitly include inundation. Our approach considers both far- and near-field sources. Based on the approach described by Lorito et al. (2008), we identified a few Source Zones (SZ), each of which is characterized by a Typical Fault (TF) floating within it and capable of generating the Maximum Credible Earthquake (MCE). Some of the MCE recall historical events such as the 1908 Messina, the 1693 Catania and the 365 AD Crete earthquakes. We calculated the combined probability for all considered SZs by assigning a recurrence interval to each of them and a Poisson distribution of the inter-event times. We performed the PTHA for different damage metrics, such as runup, current speed, momentum and Froude number, with probability of exceedance of given thresholds being evaluated for different time intervals.

Description: Published

Description: San Francisco

Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale

Description: open

Description: A new method of macroseismic surveys, based on voluntary collaboration through the Internet, has been running at the Istituto Nazionale di Geofisica e Vulcanologia (INGV) since July 2007. The macroseismic questionnaire is addressed to a single non-specialist; reported effects are statistically analysed to extrapolate a probabilistic estimate of Mercalli Cancani Sieberg and European Macroseismic Scale intensities for that observer. Maps of macroseismic intensity are displayed online in almost real time and are continuously updated when new data are made available. For densely inhabited zones, we have received reports of felt effects for even very small events (M=2). Six earthquakes are presented here, showing the ability of the method to give fast and interesting results. The effects reported in questionnaires coming from three towns are carefully analysed and assigned intensities are compared with those derived from traditional macroseismic surveys, showing the reliability of our web-based method

Description: EU FP6 NEST Pathfinder programme TRIGS under contract NEST-2005-PATH-COM-043386 INGV-DPC 2007-2009 S1 and S3 Projects

Description: Published

Description: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale

Description: open

Description: Earthquake catalogues for Romania supply for 11th–15th century earthquakes located in the region of Vrancea records that consist of a complete set of parameters, including magnitude and depth. Scope of this paper is to verify the reliability and consistency of these parameters with the informative background as explicitly referenced by the catalogues. After retrieving the original sources they mention, the set of data appeared to be related almost exclusively to the Russian plain and too poor to be at the very origin of the parameter assessment. Data for 19th–20th century earthquakes, such as instrumental locations and CMT solutions, added to the understanding of the macroseismic response of the Russian plain to Vrancea earthquakes. On the one hand, the investigation and analysis of historical earthquake records for the fourteen events listed by the catalogues in the 11th–15th centuries has shown that for three earthquakes (1022, 1038, 1258) no primary sources could be traced, and three more earthquakes (1091, 1170 and 1328) are attested only by scarcely reliable records and had to be classified as doubtful, and one (1473) is simply a duplication of the 1471 event. On the other hand, the availability of data on recent earthquakes that may be compared to historical ones in terms of macroseismic effects allowed the authors to agree with the previous catalogue compilers’ solution with regard to both magnitude and depth of the past earthquakes for which do exist reliable primary historical records.

Description: Published

Description: 575–604

Description: 4IT. Banche dati

Description: JCR Journal

Description: open

Description: Petroleum seeps have historically been important drivers of global petroleum exploration. Still today they can serve as direct indicators of gas and/or oil subsurface accumulations. In particular the assessment of the origin of seeping gas is a key task for understanding, without drilling, the subsurface hydrocarbon potential, genesis and quality; e.g., the presence of shallow microbial gas, deeper thermogenic accumulations, the presence of oil and non-hydrocarbon undesirable gases (CO2, N2, H2S). Seeps are then indicators of tectonic discontinuities (faults) and fractured rocks; they can also represent geo-hazards and sources of greenhouse gas (methane) and photochemical pollutants (ethane and propane). A new global dataset of onshore gas and oil seeps (GLOGOS) is here presented. GLOGOS includes more than 1150 seeps from 84 countries (version August 2009), and it is continuously updated and expanded. The dataset includes geographical and gas-geochemical data (molecular and isotopic composition of the main gases). Many seeps are recently discovered or never reported in other databases. Seeps are catalogued by country and classified in three types: gas seeps, oil seeps and mud volcanoes. All seeps have a bibliographic or www reference. GLOGOS is a unique tool for hydrocarbon exploration, assessment of Total Petroleum Systems and geo- structural studies.

Description: Published

Description: Article #70071

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

Description: N/A or not JCR

Description: open

Description: The Lake Albano is situated in the Colli Albani volcanic district, about 20 km SE from the city centre of Rome. It is 287 m above sea level and is the deepest among the volcanic crater lakes of Italy, being presently 167 m deep. It is 3.5 km long and 2.3 km wide with an area of about 6 km2. The crater has a long history, which starts with the formation of the Albano crater ~70 ka B.P., and shows evidence of human settlements since pre-historical times. Geological evidence indicates that a catastrophic overflow of the lake occurred in 396 B.C.E. due to a rapid increase of the water level. This phenomenon persuaded the Romans to excavate an artificial outlet though the crater wall to control the lake level. The lake is thought to be hazardous for the surroundings human settlements and the city of Rome, high resolution multibeam bathymetry of the of Lake Albano was performed for the Italian Dipartimento della Protezione Civile, in order to evaluate the potential for CO2 storage and eruption from the lake. The shape of the crater floor was mapped in 2-D and 3-D. Here, we show the main submerged morphological features and a brief history of the lake level changes, which still affect this basin today.

Description: Published

Description: 229-244

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

Description: open

Description: The number of tornillo events has recently increased at the Vulcano Island, Italy. While only 15 tornillos were recorded during 2004–2006, 584 events occurred in 2007–2008. They were located just below La Fossa Crater at depths ranging between 0.1 and 1 km b.s.l. During two intervals in 2007–2008 increases in the number of tornillos took place at the same time as temperature and geochemical anomalies were observed. The spectral content of the tornillos, generally characterized by one–two dominant spectral peaks near 6 and 10 Hz, varied over time, with changes also noted in the quality factors. The simplest source mechanism proposed for tornillos is the free eigenvibration of a fluid volume within a crack or a conduit. Based on this model, we propose a causal relationship between the temperature and geochemical anomalies and the increases in numbers of tornillos. As the amount of hydrothermal fluids increases during the anomalies, the upward flux of fluids grows. The consequent changes in the pressure, temperature and dynamics of the system of cracks and conduits result in the generation of tornillos. Based on the fluid-filled crack/conduit model, the shallow depths of the sources and the values of the quality factors, the fluid within the resonant crack/conduit was inferred to be an ash–gas or water droplet–gas mixture. Moreover, the observed variations in the wavefield can be caused by small changes in the location of the source, in the source mechanism, or in the medium in between the source and the seismic station. Finally, another peculiar feature of tornillos is the amplitude modulation that can be explained as a result of a beating phenomenon.

Description: Published

Description: 377-393

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

Description: JCR Journal

Description: reserved

Description: CUMAS is an underwater module developed for the acquisition of geophysical signals in shallow sea# oor for geohazard monitoring in volcanic areas. It was conceived for a speci! c application in the Campi Flegrei Caldera (Southern Italy) where the main features of the present volcanic activity consists of slow soil movements (bradyseism) accompanied by intense and shallow seismic activity. The latest strong episode occurred in the period 1982-84 with a ground uplift of more than 170 cm followed by a slow and continuous subsidence still ongoing with of small amplitude uplift episodes (few centimeters). It is worth noting that the seismic activity only appears during the uplift phase.

Description: Published

Description: 31-32

Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive

Description: N/A or not JCR

Description: open

Description: Na–HCO3–CO2-rich thermomineral waters issue in the N of Portugal, within the Galicia-Trás-os-Montes region, linked to a major NNE-trending fault, the so-called Penacova-Régua-Verin megalineament. Along this tectonic structure different occurrences of CO2-rich thermomineral waters are found: Chaves hot waters (67 °C) and also several cold (16.1 °C) CO2-rich waters. The δ2H and δ18O values of the thermomineral waters are similar to those of the local meteoric waters. The chemical composition of both hot and cold mineral waters suggests that water–rock reactions are mainly controlled by the amount of dissolved CO2 (g) rather than by the water temperature. Stable carbon isotope data indicate an external CO2 inorganic origin for the gas. δ13CCO2 values ranging between −7.2‰ and −5.1‰ are consistent with a two-component mixture between crustal and mantle-derived CO2. Such an assumption is supported by the 3He/4He ratios measured in the gas phase, are between 0.89 and 2.68 times the atmospheric ratio (Ra). These ratios which are higher than that those expected for a pure crustal origin (≈0.02 Ra), indicating that 10 to 30% of the He has originated from the upper mantle. Release of deep-seated fluids having a mantle-derived component in a region without recent volcanic activity indicates that extensive neo-tectonic structures originating during the Alpine Orogeny are still active (i.e., the Chaves Depression).

Description: Published

Description: 49-56

Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi

Description: JCR Journal

Description: reserved

Description: The Colfiorito Mw 6.0 (September 26, 1997, 09:40 UTC) and the Sellano Mw 5.6 (October 14, 1997) normal faulting earthquakes are the two strongest events of the 1997–1998 Umbria–Marche seismic sequence (central Italy). They provided accelerograms recorded at epicentral distances within nearly two fault lengths. Previous studies on these events revealed clear evidence of unilateral rupture propagation and directivity effects on the source time functions We developed an approximate procedure to correct the observed peak ground motion for the site effects, and we found a systematic increase of peak ground acceleration (PGA) and peak ground velocity (PGV) at sites located in the direction of the rupture propagation respect to the stations located to the backward. In particularwe showed that, for the Colfiorito earthquake, the average PGV at the north-west sites is 2.8 times larger than the PGV at south-east sites (2.1 for PGA); an opposite behaviour is found during the Sellano earthquake, with an amplification factor of about 1.9 for PGV (1.5 for PGA) recorded at south-east sites respect to the north-west stations.We explained these behaviours in terms of directivity effect, by comparing recorded ground accelerations with synthetics simulated by a deterministic–stochastic technique. This method computes high-frequency ground motions (fN0.5 Hz) from extended faults, generalizing the point-source stochastic method to capture the essence of near-source effects. The synthetic PGAs decrease with distance in agreement with the ground-motion empirical predictive model available for the area and describe the azimuthal variation of recorded data in terms of source effects.

Description: Published

Description: 110-120

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: JCR Journal

Description: reserved

Description: We present the results of a study of volcanic gases at Soufrière Hills Volcano, Montserrat, which includes the first spectroscopic measurements of the major gas species CO2 and H2S at this volcano using a Multisensor Gas Analyzer System (MultiGAS) sensor. The fluxes of CO2 and H2S were 640–2750 t/d and 84–266 t/d, respectively, during July 2008, during a prolonged eruptive pause. The flux of CO2 is similar to estimates for the entire arc from previous geochemical studies, while the measured H2S flux significantly alters our interpretation of the sulphur budget for this volcano. The fluxes of both sulphur and carbon show considerable excesses over that which can be supplied by degassing of erupted magma. We demonstrate, using thermodynamic models and published constraints on preeruptive volatile concentrations, that the gas composition and fluxes are best modeled by mixing between (1) gases derived from isobaric quenching of mafic magma against cooler andesite magma at depth and (2) gases derived from shallower rhyolitic interstitial melt within the porpyritic andesite. The escape of deep‐derived gases requires pervasive permeability or vapor advection extending to several kilometers depth in the conduit and magma storage system. These results provide more compelling evidence for both the contribution of unerupted mafic magma to the volatile budget of this andesitic arc volcano and the importance of the intruding mafic magma in sustaining the eruption. From a broader perspective, this study illustrates the importance and role of underplating mafic magmas in arc settings. These magmas play an important role in triggering and sustaining eruptions and contribute in a highly significant way to the volatile budget of arc volcanoes.

Description: Published

Description: Q04005

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

Description: JCR Journal

Description: restricted

Description: In Ecuador, magmatism results from the subduction of the Nazca Plate beneath the North Western part of South America (Pennington, 1981; Kellogg and Vega, 1995; Witt et al., 2006). North of 2.5°S, the Ecuadorian Quaternary volcanic arc is characterized by about 60 volcanoes distributed in three different parallel chains. Many of these volcanoes are potentially active or currently in activity and display associated geothermal fields. South of this latitude, no active arc is present in Ecuador. Few geochemical studies of the discharged fluids have been attempted, mainly related to geothermal exploration. Nevertheless, a complete study of the fluids of the volcanic arc is lacking. The aim of this work is to present the first systematic geochemical characterization of discharged fluids from the entire Ecuadorian volcanic arc. In order to achieve this objective, 48 samples of thermal and cold waters, as well as bubbling gases, have been collected from North to South across the arc and analyzed for different geochemical parameters. A chemical study reflects the physical and chemical processes undergone by these cold and thermal waters during their circulation through the different host rocks. The chemistry of the dissolved gases, as characterized by He and CO2 contents, which are – 2 to 3 orders of magnitude higher than the ASW values - implies very active gas-water interaction processes. Moreover, the isotopic signature of dissolved and bubbling gases shows a wide compositional range, with Helium isotopic compositions ranging between 0.34 to 7.12 R/Ra and carbon isotopes compositions ranging from -1.75 to -10.50 13C Vs PDB standard. This clearly indicates the presence of at least three distinct end-members: mantle, crustal and geothermal. Helium, Nitrogen, Carbon, Oxygen and Deuterium isotopic signatures will help us to identify and characterize the main end-members of fluids involved in Ecuador’s arc-volcanism. Moreover, on the basis of the chemistry of thermal waters and associated bubbling gases the characteristics and the potential resources of the different geothermal fields are being investigated.

Description: Published

Description: Cluj-Napoca, Romania

Description: 2.4. TTC - Laboratori di geochimica dei fluidi

Description: open

Description: New 40Ar/39Ar and 14C ages have been found for the Albano multiple maar pyroclastic units and underlying 25 paleosols to document the most recent explosive activity in the Colli Albani Volcanic District (CAVD) near 26 Rome, Italy, consisting of seven eruptions (Albano 1 27 ^ = ^ oldest). Both dating methodologies have been applied on several proximal units and on four mid-distal fall/surge deposits, the latter correlated, according to two 28 current different views, to either the Albano or the Campi di Annibale hydromagmatic center. The 40Ar/39Ar 29 ages on leucite phenocrysts from the mid-distal units yielded ages of ca. 72 ka, 73 ka, 41 ka and 36 ka BP, 30 which are indistinguishable from the previously determined 40Ar/39Ar ages of the proximal Albano units 1, 2, 31 5 and 7, thus confirming their stratigraphic correspondence. 32 Twenty-one 14C ages of the paleosols beneath Albano units 3, 5, 6 and 7 were found for samples collected 33 from 13 proximal and distal sections, some of which were the same sections sampled for 40Ar/39Ar 34 measurements. The 14C ages were found to be stratigraphically inconsistent and highly scattered, and were 35 systematically younger than the 40Ar/39Ar ages, ranging 36 ^ from 35 ka ^ to 3 ka. Considering the significant consistence of the 40Ar/39Ar chronological framework, we interpret the scattered and contradictory 14C ages 37 to be the result of a variable contamination of the paleosols by younger organic carbon deriving from the 38 superficial soil horizons. 39 These results suggest that multiple isotopic systems anchored to a robust stratigraphic framework may need 40 to be employed to determine accurately the geochronology of the CAVD as well as other volcanic districts. 41

Description: Published

Description: 203-213

Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi

Description: JCR Journal

Description: open

Description: Spurred by the sustained operation and new development of satellite and in-situ observing systems, global ocean state estimation efforts that gear towards climate applications have flourished in the past decade. A hierarchy of estimation methods is being used to routinely synthesize various observations with global ocean models. Many of the estimation products are available through public data servers. There have been an increasingly large number of applications of these products for a wide range of research topics in physical oceanography as well as other disciplines. These studies often provide important feedback for observing systems design. This white paper describes the approaches used by these estimation systems in synthesizing observations and model dynamics, highlights the applications of their products for climate research, and addresses the challenges ahead in relation to the observing systems. Additional applications to study climate variability using an ensemble of state estimation products are described also by a white paper by Stammer et al.

Description: Published

Description: Venice, Italy

Description: 3.7. Dinamica del clima e dell'oceano

Description: open

Description: In austral winter large regions of the Southern Ocean are covered by seasonal sea ice which disappears in summer. Only in few regions sea ice persists during the summer and becomes second year ice. Most of this second year ice is located in the Weddell Sea, making this region particularly interesting. The variation of the ice covered area modifies the exchange of heat, mass and momentum between ocean and atmosphere. Therefore knowledge of ice extent and its variability is necessary for an adequate simulation of those fluxes and thus for climate modelling. The goal of this study is the observation of interannual and seasonal ice extent variations and their underlying causes in the Weddell Sea. Variability is analysed by using microwave satellite data. Results are correlated with satellite derived sea ice drift data and with ice drift fields calculated from a Finite Element Sea ice-Ocean Model (FESOM) to determine the impact of ice drift variations on sea ice extent. An additional cause for variations of ice extent could be different ice type distributions, i.e. the contribution of first and second year ice to the total ice covered area. These ice types are determined on monthly time scales from scatterometer satellite data for the years 2000 to 2007 and will be extended backward in time using the ice thickness distribution modelled by FESOM. Ice class distribution and sea ice drift variability are compared with the characteristics and variability of meteorological behaviour to evaluate the relative importance of different sea ice parameters for shaping Weddell Sea ice extent and its variability.

Description: Petroleum systems located at passive continental margins received increasing attention in the last decade mainly because of deep- and ultra‐deep-water hydrocarbon exploration and production. The high risks associated with these settings originate mainly from the poor understanding of inherent geodynamic processes. The new priority program SAMPLE (South Atlantic Margin Processes and Links with onshore Evolution), established by the German Science Foundation in 2009 for a total duration of 6 years, addresses a number of open questions related to continental breakup and post‐breakup evolution of passive continental margins. 27 sub‐projects take advantage of the exceptional conditions of the South Atlantic as a prime “Geo‐archive.” The regional focus is set on the conjugate margins located east of Brazil and Argentina on one side and west of Angola, Namibia and South Africa on the other (Figure 1) as well as on the Walvis Ridge and the present‐day hotspot of Tristan da Cunha. The economic relevance of the program is demonstrated by support from several petroleum companies, but the main goal is research on fundamental processes behind the evolution of passive continental margins.

Description: The software PanXML is a tool to create XML files needed for DOI registration at the German National Library of Science and Technology (TIB). PanXML is distributed as freeware for the operating systems Microsoft Windows, Apple OS X and Linux. An XML file created by PanXML is based on the XSD file article-doi_v3.2.xsd. Further schemas may be added on request.

Description: A semi-analytical model of the Panama throughflow is presented. The model expresses the throughflow transport as a function of deep water formation in the North Pacific and in the North Atlantic, and of the Panama Gateway depth. The model is derived from the integral of the momentum equation along a circumpolar path, and can be interpreted from the point of view of the vorticity balance. The important conditions are whether the deep water, whose location is considered to be above the bottom water formed around Antarctica, originates from the North Atlantic or from the North Pacific, and whether the Panama Gateway is shallower than the lower boundary of the deep water. The present model indicates that the barotropic transport through the Panama Gateway is eastward, except for the case where the deep water is formed in the North Pacific and the sill of the Panama Gateway is shallow. The baroclinic structure of the Panama throughflow depends on whether the deep water is formed in the North Pacific or in the North Atlantic. These qualitative implications of the model are consistent with recent numerical studies and proxy-based paleoceanographic studies. Numerical experiments performed in the present study reinforce confidence in the semi-analytical model.

Description: Although the filter-transfer-freeze (FTF) technique is considered among the classical approaches for cell counting and identification, it is not specifically a cell enumeration method, but rather a means of cell concentration, collection, and transfer for counting by alternative means. When applied correctly, the accuracy and reproducibility of cell counts performed by the FTF technique is more a function of the subsequent counting and identification methods than of the FTF procedure itself. The FTF method was introduced more than two decades ago (Hewes and Holm-Hansen 1983), but in spite of its simplicity and proven effectiveness, the method has not been widely employed. This is regrettable because the FTF method can be applied for both critical taxonomy (with some caveats) and for rapid but superficial analysis of phytoplankton samples. The original method was designed with respect to nanoplankton and indeed appears to work best for taxa in the size range of ca. 5 – 200 μm diameter. Smaller cells tend to get lost to the filter and larger organisms do not transfer well. Nevertheless, this size-range embraces most of the diatoms and nanoflagellates of interest and chain-formation does not markedly decrease transfer efficiency from the filter to slide.

Description: Transport of sea ice through Fram Strait affects the global climate through its influence on the thermohaline circulation. In recognition of its importance, the ice thickness distribution across Fram Strait and in the area north of Greenland was subject of the TIFAX 2010 field campaign. The ice thickness was investigated by means of an airborne electromagnetic (EM) system with a single-frequency of 4.08 kHz. The instrument was towed by a research aircraft (Polar 5) 15 meters above the ice surface. The method utilizes the contrast of electrical conductivity between sea water and sea ice to determine the distance to the ice-water interface. An additional laser altimeter yields the distance to the uppermost reflecting surface, hence ice thickness is obtained as the ice- plus snow thickness from the difference between the laser range and the EM derived distance. In this data report, all tracks/profiles taken during TIFAX 2010 are presented.

Description: Enhanced glacier and polar ice sheet melting during the last decades is one of the major focuses of geosciences. The understanding of the effects of future global warming is important due to raising sea level. Antarctic ice masses play a key role in global climate. Melting of Antarctic ice would result in a sea level rise of about ~3-6 m due to the West Antarctic Ice Sheet and 60 m due to the East Antarctic Ice Sheet. Because of its marine-based nature, especially the West Antarctic Ice Sheet is sensitive to rising temperatures. Additionally, the Ross Sea, as a part of the west Antarctic system, and its shelf are a key region stabilizing the west Antarctic ice masses. It is thus essential to understand the processes and changes in this area in order to interpret the past and predict the future climate developments. Sedimentary archives are a unique opportunity to get insights into past climate variability and the ice response due to increased temperature (~3°C), as the earth had experienced in the last 14 Ma since the mid Miocene cooling. The multi-national drilling program ANDRILL (ANtarctic geological DRILLing, McMurdo Ice Shelf project, MIS) focuses on the changes of climatic influences on the West Antarctic Ice Sheet during the past ~14 Ma. During austral summer 2006/07, an approximately 1300 m long sedimentary succession beneath the northwestern Ross Ice Shelf was cored. In this study geochemical investigations were carried out and interpreted using a multiproxy approach. The results of major element measurements from X-ray fluorescence on discrete samples and high-resolution non-destructive XRF analyses on split-cores, using an XRF core scanner, total organic carbon, total inorganic carbon, opal, and mineral data, as well as optical microscope and visual colour reflectance investigations were used to reveal different processes controlling the depositional environment in the southern Ross Sea. Provenance analyses reveal three main sources for fine-grained terrigenous sediments at the MIS site. First, close-by McMurdo Group volcanoes (MVG) are a source for sedimentary deposits of AND-1B (mainly diamictites) during times of extended glaciations. Second, in interglacial periods, sediment composition (mainly mudstones) is controlled by southern Transantarctic Mountains (S TAM) and finally a geochemical mixture of both sources is visible in the record, which also can be indicative for a western Transantarctic Mountain source (W TAM). According to sediment architecture (McKay, 2008) and source, different transport mechanisms are existing. MVG sediments are mainly transported by subglacial erosion, whereas S TAM and W TAM sediments represent ice proximal to distal conditions with transport processes such as fluvial meltwater and gravity flows. The entire AND-1B core can be divided into 5 major sections of provenance. These geochemical facies (GCF) represent colder phases during Late Miocene and Late Pleistocene (GCF1, dominated by MVG); warm intervals during early Pliocene and late Pliocene are dominated by input from southern provenances (GCF 2), and oscillations between material from MVG and W TAM dominate the mid Pliocene (GCF 3). In sedimentary successions indicating glacial terminations and extended sea ice conditions dolomite, Fe-dolomite siderite and other traces of carbonate minerals were found. Micritic crystal size and distribution within the sediment matrix reveal an authigenic, early diagenetic precipitation. These precipitates form in concert with freezing processes that result in a hyper-saline brine formation, saturating pore waters with respect to dolomite phases. Within the layers of hyper-saline brines, dolomite or unstable carbonate phases occur that are later on recrystallized to dolomite. An additional factor for dolomite formation is sulphate reduction, indicated by pyrite and biomarkers of sulphate reducing bacteria. The features of the AND-1B dolomite are likely to be transferable to global cap-carbonates of Precambrian times and can be likely an explanation for dolomite formation due to rapid deglaciations at glacial terminations. During open water conditions in the southern Ross Sea, when no West Antarctic Ice Sheet had existed (Naish et al., 2009), mass accumulation and paleoproductivity estimations from the AND-1B record reveal the Ross Sea as a high production area during Pliocene and Pleistocene. Opal accumulation is in the same ranges as for modern analogues in front of the present Ross Ice Shelf edge and even higher during specific times in the Pliocene. In contrast, paleoproduction and organic carbon accumulation rates are low and reveal a decoupling between organic carbon and opal preservation, where opal evidences good preservation efficiency while organic carbon shows low preservation rates. These results suggest that the Ross Shelf was an oxic environment with strong organic carbon degradation during the Pliocene. Nevertheless, accumulation of organic carbon was high enough to make the Ross Shelf a major sink for organic carbon. In a global comparison, the Ross Sea area removed more carbon from the atmospheric CO2 cycle as some highly productive up-welling systems do.

Description: Recent advances in three‐dimensional (3D) imaging of snow and firn combined with numerical modeling of flow through complex geometries have greatly improved the ability to predict permeability values based on microstructure. In this work, we combined 3D reconstructions of polar firn microstructure obtained from microcomputed tomography (mCT) and a 3D lattice‐Boltzmann (LB) model of air flow. We compared the modeled results to measurements of permeability for polar firn with a wide range of grain and pore‐scale characteristics. The results show good agreement between permeability measurements and calculated permeability values from the LB model over a wide range of sample types. The LB model is better at predicting measured permeability values than traditional empirical equations for polar firn.

Description: A 47-yr (1958-2004) model simulation has been analyzed to identify changes of the southern North Sea hydrodynamic regime in the past. A time series analysis revealed time points of changes in volume transports which correspond to recently described changes in the North Sea ecosystem (‘regime shifts’). The strengths of these hydrodynamic changes are shown to vary on a regional scale. Being interested in the analysis of long-term time series (starting in 1962) of hydrophysical and biological parameters measured at the island of Helgoland (54°11.3’ N, 7°54.0’ E, German Bight) we studied seasonal and interannual variations of the North Sea hydrodynamic regime with respect to their effects on the Helgoland area. An Empirical Orthogonal Function (EOF) analysis of spatial patterns of passive tracer Lagrangian transports has been carried out to describe the temporal variability of water mass advection. It could be shown that the southern inflow to the North Sea (via the English Channel) has strengthened since the end of the 70s and that the degree of its impact in the Helgoland area has changed. These regional effects of large-scale hydro-meteorological changes are also discussed in terms of its connection with variations of the NAO index.

Description: The coastal fringe off northern Chile (18º-23ºS) is inhabited by numerous neritic fish species of which 249 are commonly observed during normal and cold La Niña (LN) conditions. During El Niño (EN) the ichthyofauna of northern Chile changes significantly due to about 100 invading fish species normally inhabiting lower latitudes, named “septentrional invaders” and “tropic-equatorial fishes”. This results in a composition including 15 fish families and 86 genera. Analyses showed that species affected by EN were not the same between the last three EN events revealing that only the epipelagic species Anchoa naso, Albula vulpes, Atherinella nocturna and Scomberesox saurus stolatus behaved consistently. Off northern Chile, EN 1982/83, 1986/87, 1991/92, 1997/98, 2002/2003 and the not clearly EN defined 2004/2005 period with their aligned thermal abnormalities of each particular event were directly related to the number of invading/affected species. Most of the alien species (〉50%) were epipelagic, 25% were typical for sandy beaches and 14.6% for rocky shores. The shore fish community did not show major changes during and after EN events, as only a few invading species were recorded; just Umbrina xantii was found during all events considered. In order to understand the response of the fish community to ENSO events a biogeographical analyses of 721 fish species reported for neritic habitats (coastal epipelagic and benthic) distributed between 0°-57°S (Gulf of Guayaquil to Cape Horn) was made. Their distribution ranges for normal oceanic conditions were taken from the very numereous existing literature. It is concluded that the north/south migration of Panamic and Peruvian warm water fishes during EN/LN events along the north Chilean coast between 18º-23ºS, indicates that it represents a wide transition zone between the Peruvian and the Chilean ichthyogeographic provinces.

Description: In der Sporrtraumatologie bzw. orthopädischen Sportmedizin hat der Einsatz biodegradierbarer Implantate eine explosionsartige Verbreitung gefunden. Der Gründe hierfür mögen die geringen Belastungen, denen ein biodegradierbares Implantat in der Kapsel-Bandchirurgie ausgesetzt ist, sein. Die Ursache mag in den geringeren Belastungen zu finden sein, denen ein biodegradierbares Implantat in der Kapsel-Bandchirurgie ausgesetzt ist und der Tatsache, dass der Vorteil der ungestörten Revisionschirurgie und einer ungestörten bildgebenden Diagnostik hier von wesentlicher Bedeutung ist. Diese explosionsartige Verbreitung hat jedoch dazu geführt, dass biodegradierbare Interferenzschrauben, Fadenanker und Meniskusrefixationssysteme unabhängig von ihren ungenügend getesteten mechanischen Eigenschaften und ihrer ungenügend untersuchten Biokompatibilität bzw. Degradation zunehmend eingesetzt wurden. Diese Arbeit beschreibt unter anderem, warum Hydroxylapatit als Knochenersatz dient und wie Beispiele aus der Natur- speziell Muscheln wie der Tectus triserialis oder der Rhinoc/avis si11ense - für Strukturen von Interferenzschrauben als Vorbild fungieren können. Hauptaugenmerk liegt hierbei auf der Verkürzung der Regenerationszeit, um somit eine möglichst frühe Belastung zu ermöglichen. In Kombination mit bereits aus der Industrie angewendeten Bauformen von Interferenzschrauben für die Transplantatverankerung wird hier eine Modeliierung gefertigt.

Description: The Tibetan Plateau is the largest elevated landmass in the world and profoundly influences atmospheric circulation patterns such as the Asian monsoon system. Therefore this area has been increasingly in focus of palaeoenvironmental studies. This thesis evaluates the applicability of organic biomarkers for palaeolimnological purposes on the Tibetan Plateau with a focus on aquatic macrophyte-derived biomarkers. Submerged aquatic macrophytes have to be considered to significantly influence the sediment organic matter due to their high abundance in many Tibetan lakes. They can show highly 13C-enriched biomass because of their carbon metabolism and it is therefore crucial for the interpretation of δ13C values in sediment cores to understand to which extent aquatic macrophytes contribute to the isotopic signal of the sediments in Tibetan lakes and in which way variations can be explained in a palaeolimnological context. Additionally, the high abundance of macrophytes makes them interesting as potential recorders of lake water δD. Hydrogen isotope analysis of biomarkers is a rapidly evolving field to reconstruct past hydrological conditions and therefore of special relevance on the Tibetan Plateau due to the direct linkage between variations of monsoon intensity and changes in regional precipitation / evaporation balances. A set of surface sediment and aquatic macrophyte samples from the central and eastern Tibetan Plateau was analysed for composition as well as carbon and hydrogen isotopes of n-alkanes. It was shown how variable δ13C values of bulk organic matter and leaf lipids can be in submerged macrophytes even of a single species and how strongly these parameters are affected by them in corresponding sediments. The estimated contribution of the macrophytes by means of a binary isotopic model was calculated to be up to 60% (mean: 40%) to total organic carbon and up to 100% (mean: 66%) to mid-chain n-alkanes. Hydrogen isotopes of n-alkanes turned out to record δD of meteoric water of the summer precipitation. The apparent enrichment factor between water and n-alkanes was in range of previously reported ones (≈-130‰) at the most humid sites, but smaller (average: -86‰) at sites with a negative moisture budget. This indicates an influence of evaporation and evapotranspiration on δD of source water for aquatic and terrestrial plants. The offset between δD of mid- and long-chain n-alkanes was close to zero in most of the samples, suggesting that lake water as well as soil and leaf water are affected to a similar extent by those effects. To apply biomarkers in a palaeolimnological context, the aliphatic biomarker fraction of a sediment core from Lake Koucha (34.0° N; 97.2° E; eastern Tibetan Plateau) was analysed for concentrations, δ13C and δD values of compounds. Before ca. 8 cal ka BP, the lake was dominated by aquatic macrophyte-derived mid-chain n-alkanes, while after 6 cal ka BP high concentrations of a C20 highly branched isoprenoid compound indicate a predominance of phytoplankton. Those two principally different states of the lake were linked by a transition period with high abundances of microbial biomarkers. δ13C values were relatively constant for long-chain n-alkanes, while mid-chain n-alkanes showed variations between -23.5 to -12.6‰. Highest values were observed for the assumed period of maximum macrophyte growth during the late glacial and for the phytoplankton maximum during the middle and late Holocene. Therefore, the enriched values were interpreted to be caused by carbon limitation which in turn was induced by high macrophyte and primary productivity, respectively. Hydrogen isotope signatures of mid-chain n-alkanes have been shown to be able to track a previously deduced episode of reduced moisture availability between ca. 10 and 7 cal ka BP, indicated by a 20‰ shift towards higher δD values. Indications for cooler episodes at 6.0, 3.1 and 1.8 cal ka BP were gained from drops of biomarker concentrations, especially microbial-derived hopanoids, and from coincidental shifts towards lower δ13C values. Those episodes correspond well with cool events reported from other locations on the Tibetan Plateau as well as in the Northern Hemisphere. To conclude, the study of recent sediments and plants improved the understanding of factors affecting the composition and isotopic signatures of aliphatic biomarkers in sediments. Concentrations and isotopic signatures of the biomarkers in Lake Koucha could be interpreted in a palaeolimnological context and contribute to the knowledge about the history of the lake. Aquatic macrophyte-derived mid-chain n-alkanes were especially useful, due to their high abundance in many Tibetan Lakes and their ability to record major changes of lake productivity and palaeo-hydrological conditions. Therefore, they have the potential to contribute to a fuller understanding of past climate variability in this key region for atmospheric circulation systems.

Description: N/A

Description: Published

Description: 75-83

Description: 4.1. Metodologie sismologiche per l'ingegneria sismica

Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale

Description: N/A or not JCR

Description: reserved

Description: The goal of this PhD thesis is to provide an overview on the very different aspects of modern gravimetric research. In particular, this geophysical method is applied here on the one hand as volcano monitoring tool essentially by continuous gravity observations while, on the other hand, for the construction of density-velocity 3D regional models by an integrated inversion procedure of gravimetric and seismic data. The first section concentrates on continuous gravity observation performed at different sites of both Etna and Stromboli volcanoes. The gravity studies allow investigation of mass displacements (magma) and density variations (deep structures) under volcano edifices. Results are presented from high precision gravity measurements fully corrected using tidal and drift optimization programs and having a standard error of few μgal. Tidal analyses results of the treated data sets are also shown and discussed in the first section. Moreover, the simultaneous recording of external parameters (atmospheric pressure, temperature and humidity) is essential as their effects must be removed from the gravity records. The analyses carried out with different processing techniques on several data sets led us to point out the temperature as the responsible parameter for the annual drift present in the records of spring gravimeters. During the end of 2002 one of the gravimetric signals acquired on Mt. Etna showed, in its final residuals reaching a 5 μgal precision, a strong decrease of about 400 μgal in few hours. Correlation between this gravity decrease, on the one hand, and the other geophysical and geochemical signals – in particular the seismic and ground deformation data – as well as the observed summit activities, on the other hand, enable us to qualify the recorded gravity variation as a precursor of the 2002 eruption period. By comparison with simultaneous ground deformation data it is shown that the observed gravity changes are not in general caused by elevation changes but are due to the direct gravitational effect of subsurface movements of matter. Residual gravity changes are interpretable entirely in terms of mass changes in crater conduits and in near-surface dykes lying along know fissure system. Furthermore, the summit activity is consistent with a source at greater depth. Gravity measurements may thus not only contribute to a better understanding of some important features of geodynamics in volcanoes but may also be used directly for the monitoring and the prediction of the eruptions. Section two addresses the unresolved question of the possible interference between tidal forces and volcanism. After the discussion of gravimetric tide results and the determination of tidal parameters, this section is completely devoted to “tidal modulation” of thermometric data acquired at sites very close to the summit active craters of Mt Etna. The intuition that these types of data may contain some geophysical signals related to the tidal stress-strain action, as an evidence of the tidal influence on volcanic processes, comes from the following boundary consideration: since the volcanic areas are characterised by high heat fluxes due to the presence of magma bodies near the surface, taking into account that convection is the major heat transfer mechanism, the tidal strain field within the volcanic edifice could affect this convective process. Some time variations of the efficiency of the convective process should produce corresponding temperature changes observable at shallow depth. The aim of the study is thus to investigate about the presence of a periodic variation due to the main lunar tidal component (M2, tidal period of 12.421 hours). This component is chosen in order to rule out the solar radiation effects. The data set at hand was thus processed with a stacking technique coupled with a wavelet analysis for a preliminary denoising. Through the proposed procedure an anomalous amplitude of the spectral component with a period equal to that of the M2 tidal wave was found. This evidence opens a scientific speculative argument about the interaction between tidal forces and volcanic processes highlighting the possibility, under some particular conditions, of dynamic triggering. The last section deals with a seismo-gravity integrated inversion procedure for the construction of reliable 3D models of the Sicilian area and its surrounding basins. The proposed procedure allows inverting seismic and gravimetric data with a sequential technique to avoid the problematic optimization of assigning relative weights to the different types of data. The proposed procedure underlined the necessity of the different data integration although the seismic problem seemed to be a priori well constrained. Furthermore, it allowed highlighting some velocity and density features that could play a crucial rule for the reconstruction of the geodynamic evolution of the study area.

Description: Università degli studi di Palermo, I.N.G.V. sezione di Catania, International Center for Earth Tides (Royal Observatory of Belgium)

Description: Unpublished

Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive

Description: open

Description: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union

Description: Instrumental seismicity of the greater Rome area is analyzed using the most recent seismological database. The aim of this study is to identify potential seismogenic structures responsible for the moderate seismicity that characterizes this sector, where no surface faulting is expected on the basis of the absence of strong local earthquakes, as evidenced by the 2000‐year‐long historical record. Nevertheless, in light of the great value and the high vulnerability of the architectural and monumental patrimony of Rome, even the occurrence of moderate events imposes a careful assessment of the hazard, linked to the presence of active faults that are undetectable by means of classic geological field investigation. Seismic data here analyzed belong to the period 1997–2008 and show local magnitude (ML) ranging from 1.5 to 4.7. To better constrain the hypocentral depths, we computed the Vp/Vs ratio using a modified Wadati method and the minimum 1‐D velocity model that approximates the seismic structure of the study area. Moreover, we applied a double difference hypocentral determination technique to improve earthquake locations. Most of the located seismicity appears to be concentrated within seven main clusters. Spatial distribution of the seismicity allowed us to identify several seismogenic structures, corresponding to previously undetected or only supposed active faults. The stress tensor obtained by inverting the focal mechanisms computed in this study is in agreement with the NE–SW extensional tectonic stress active in the inner chain of the Apennines, although there is evidence of some local stress field heterogeneities.

Description: Published

Description: B12303

Description: 3.2. Tettonica attiva

Description: JCR Journal

Description: reserved

Description: We explore the relationships between the fracture energy density (E_G) and the key parameters characterizing earthquake sources, such as the rupture velocity (v_r), the total fault slip (u_tot), and the dynamic stress drop (Dt_d). We perform several numerical experiments of three‐dimensional, spontaneous, fully dynamic ruptures developing on planar faults of finite width, obeying different governing laws and accounting for both homogeneous and heterogeneous friction. Our results indicate that E_G behaves differently, depending on the adopted governing law and mainly on the rupture mode (pulselike or cracklike, sub‐ or supershear regime). Subshear, homogeneous ruptures show a general agreement with the theoretical prediction of E_G *proportional to* (1 - (v_r/v_S)^2)^(1/2), but for ruptures that accelerate up to supershear speeds it is difficult to infer a clear dependence of fracture energy density on rupture speed, especially in heterogeneous configurations. We see that slip pulses noticeably agree with the theoretical prediction of E_G *proportional to* u_tot^2 , contrarily to cracklike solutions, both sub‐ and supershear and both homogeneous and heterogeneous, which is in agreement with seismological inferences, showing a scaling exponent roughly equal to 1. We also found that the proportionality between E_G and Dt_d^2, expected from theoretical predictions, is somehow verified only in the case of subshear, homogeneous ruptures with RD law. Our spontaneous rupture models confirm that the total fracture energy (the integral of EG over the whole fault surface) has a power law dependence on the seismic moment, with an exponent nearly equal to 1.13, in general agreement with kinematic inferences of previous studies. Overall, our results support the idea that E_G should not be regarded as an intrinsic material property.

Description: Published

Description: B10307

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

Description: JCR Journal

Description: reserved

Description: N/A

Description: Published

Description: 15-22

Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale

Description: N/A or not JCR

Description: reserved

Description: A refined Semtner 0-layer sea-ice model (ESIM1) is presented and applied to the Baltic landfast sea-ice. The physical model is capable of simulating seasonal changes of snow and ice thickness. Particular attention is paid to reproducing the snow-ice and the super-imposed-ice formation which play important roles in the total mass balance of the Baltic sea-ice. The model prognostic variables include all kinds of ice and snow layers that may be present during a Baltic landfast ice season and, in general, in every coastal area of an ice-covered ocean. The assessment of the model capabilities was done for 1979–1993 for four different stations in the Baltic Sea. A sensitivity test stresses the relevant role of some of the physical parameters, such as the oceanic heat flux, while a scenario analysis highlights the robustness of the model to perturbed physical forcing. Our results show that one of the key variables in modelling sea-ice thermodynamics is the snow layer and its metamorphism, and including the meteoric ice dynamics into a sea ice model is relevant to properly simulate any ice season, also in view of climate change scenarios

Description: Italian FISR project VECTOR and Centro Euro-Mediterraneo per i Cambiamenti Climatici

Description: Published

Description: 68-80

Description: 3.7. Dinamica del clima e dell'oceano

Description: JCR Journal

Description: reserved

Description: Sin dalla loro introduzione, prima in forma cartacea, poi su supporti informatici, per finire alle versioni elettroniche disponibili via web, le banche dati hanno sempre rappresentato uno strumento fondamentale, indispensabile e non sostituibile della ricerca. Non di meno lo sono per i bibliotecari. Questo presupposto ci deve spingere a valorizzare sempre più il servizio di reference e di information retrieval, visto che gli strumenti a nostra disposizione aumentano di giorno in giorno, sia liberamente fruibili che sotto forma di abbonamenti annuali. Oggi le banche dati stanno varcando l’ambito per cui inizialmente erano state create e stanno per entrare in quello della valutazione della ricerca. In questo lavoro si prendono in considerazione quelle banche dati e quei motori di ricerca specialistici che oramai sono di utilizzo quotidiano in una biblioteca di scienze della terra. In particolare ci si riferirà a: Georef, Web of Science, Scirus e Google Scholar. Il lavoro inizia analizzando storicamente sia le banche dati che i motori di ricerca specialistici, per comprendere la loro natura e le motivazioni alla base della loro creazione. Si procede poi affrontando il tema della qualità del recupero dell’informazione presentata, per finire con l’analisi comparativa delle citazioni ricevute dai record estratti.

Description: Università degli studi di Roma“La Sapienza” Scuola Speciale Archivisti e Bibliotecari

Description: Unpublished

Description: 5.8. TTC - Biblioteche ed editoria

Description: open

Description: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.

Description: The time of occurrence of an earthquake is related to the state of the fault, tectonic loading, and possible triggering mechanisms, and it plays a prominent role in hazard assessment. In this paper we incorporate the effects of wear generation into a seismogenic model. We show that without wear the recurrence time of repeated earthquakes is constant through time and it is controlled by the initial conditions, tectonic loading and constitutive properties, including the presence of pore fluids. Our results indicate that considering the wear development into the fault model dramatically affects the temperature evolution of the fault, the stress release, the developed cosesimic slip and ultimately the duration of the seismic cycle. Moreover, we find that as long as the slipping zone thickness increases, the recurrence time continuously decreases through time. This further complicates the predictability of a subsequent earthquake, even in the simple case of an isolated fault.

Description: Published

Description: L20315

Description: 4.4. Scenari e mitigazione del rischio ambientale

Description: JCR Journal

Description: reserved

Description: New experiments on the viscosity of partially crystallized andesite were performed high temperature using the falling sphere methods. Because experiments with partly crystallized samples are difficult to carry out (i.e. due to high sensitivity of phase equilibria to P,T and water content), we set up a new technique to control precisely the volume fraction and the size of crystals. We simply add zircon to the melt because: a) previous study suggested that the saturation of zircon in melts of andesitic composition as a function of both temperature and composition is low, and b) easy to crush in fixed size range. Zircon-bearing magmas were synthesized at 1473 K and 300 MPa using an internally heated gas pressure vessel. All the experimental samples were then analyzed using microprobe technique. Results gave an average value of ZrO2 dissolved in the melt of about 1.6 wt %. The solubility of Zr in andesitic melt is up to two-three times higher than predicted by literature model (Watson and Harrison, 1983). Falling sphere experiments were performed using as starting material composed of dry andesitic glass, zircon crystals (15, 30 and 40 vol%) and water. The water content of the andesitic melt after experiments ranged between 0.5 and 4.08 wt%. Image analyses show that the viscosity measurements are not affected by differences in crystals shape among the samples. Falling spheres results show a viscosity 10 times higher than that of andesitic melts for samples containing 15 vol% crystals and large discrepancies from previous literature models is found in the hydrous samples. At higher vol% of crystals we did not observe any movement of the sphere. This implies that such magmas show strongly Non-Newtonian viscosity, i.e. a threshold of accelerating force needs to be passed before the sphere could move.

Description: Published

Description: 151-163

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

Description: JCR Journal

Description: reserved

Description: An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.

Description: We analyze P and S wave spectra from moderate‐ to deep‐focus teleseisms recorded at the Retreating‐Trench, Extension, and Accretion Tectonics (RETREAT) temporary broadband seismic network to assess the variations of the Earth mantle attenuation in the northern Apennines region (Italy). For each earthquake, we compute the ratio between the spectrum at each station and the average spectrum, in order to estimate t* residuals (Δt*) from the spectral ratio decay. The number and distribution of the teleseisms useable for the P wave t* calculation allow for a gross azimuthal analysis; although the (Δt*) values at single station display, in most cases, azimuthal‐dependent fluctuations, their overall distribution shows a partition of the study region into two main areas, whose gross features remain almost unchanged over the whole azimuthal range. This partition is confirmed by the S wave t* mean values, computed for each station over the set of useable events. We distinguish a relatively high attenuation area on the western, Tyrrhenian side and a relatively low attenuation area on the eastern, Adriatic side. By correlating our Δt* estimates and the velocity structure derived from the existing tomographic models, we compute the ranges of possible P and S wave Q values in the mantle wedge above the Apennines slab (on the Tyrrhenian side) and in the asthenosphere below the Adriatic region. Furthermore, the determined attenuation properties are used to draw some inferences on the thermal state of the uppermost mantle and on the physical properties of the tectonic elements, which constitute the subduction system in the region.

Description: Published

Description: B09309

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: JCR Journal

Description: reserved

Description: The postseismic response of a viscoelastic Earth can be computed analytically with a normal-mode approach, based on the application of propagator methods. This framework suffers from many limitations, mostly connected with the solution of the secular equation, whose degree scales with the number of viscoelastic layers so that only low-resolution models can be practically solved. Recently, a viable alternative to the normal-mode approach has been proposed, based on the Post-Widder inversion formula. This method allows to overcome some of the intrinsic limitations of the normal-mode approach, so that Earth models with arbitrary radial resolution can be employed and general linear non-Maxwell rheologies can be implemented. In this work, we test the robustness of the method against a standard normal-mode approach in order to optimize computation performance while ensuring the solution stability. As an application, we address the issue of finding the minimum number of layers with distinct elastic properties needed to accurately describe the postseismic relaxation of a realistic Earth model.

Description: Published

Description: Rimini, 27-30 Maggio Senigallia, 31 Maggio

Description: 3.3. Geodinamica e struttura dell'interno della Terra

Description: open