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Seismic swarm in the Chianti fiorentino (2022). The activities of the SISMIKO emergency group
No full textNel mese di maggio 2022 è iniziato uno sciame sismico, di breve durata, che ha interessato una piccola area del Chianti fiorentino a circa 15 km a sud dalla città di Firenze. I due terremoti più energetici hanno avuto una magnitudo momento pari a 3.7; nonostante la magnitudo modesta, tali eventi sono stati avvertiti distintamente fino a distanze di diverse decine di chilometri, e hanno destato preoccupazione nella popolazione prossima all’area epicentrale. Inoltre, dato l’ingente patrimonio artistico presente nel capoluogo toscano, questo episodio ha sollevato interrogativi sulla sua vulnerabilità anche a scuotimenti del suolo di piccola entità.
Al fine di migliorare le conoscenze sulla ubicazione e le dimensioni delle strutture sismogenetiche attive in prossimità di Firenze, l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) è intervenuto nell’area interessata dallo sciame attraverso il Gruppo Operativo (GO) di emergenza SISMIKO. Il 4 maggio, giorno successivo all’inizio dello sciame, cinque stazioni sismiche mobili sono state installate a distanza ravvicinata dall’area epicentrale, e integrate nel sistema di monitoraggio permanente INGV.
Questo lavoro descrive le procedure relative a: (i) l’installazione, la manutenzione e la disinstallazione della rete sismica mobile; (ii) la gestione e il controllo di qualità dei dati acquisiti. Infine, vengono presentate, in riferimento al contesto sismotettonico dell’area, le caratteristiche spaziali e l’evoluzione temporale dello sciame, che ha presentato una piccola ripresa nell’attività sismica ad agosto del 2022, con un terremoto di magnitudo locale 2.7 e successive repliche.Published1-26OST5 Verso un nuovo MonitoraggioJCR Journa
Volcano-Tectonic seismicity during the unrest phase on the island of Vulcano (Italy) from mid-September 2021 to December 2022
No full textIn mid-September 2021 there was a rapid increase in geophysical and geochemical parameters on the island of Vulcano, Italy, reaching alarming values. This phase of unrest aroused serious concern among Civil Protection, local authorities and the scientific community due to the risk of phreatomagmatic activity, with potentially serious repercussions on the inhabitants of the island and on visiting tourists.
The beginning of the unrest was marked by a high occurrence rate of local micro-seismicity related to fluid dynamics within the shallower hydrothermal system (mainly Long Period and Very Long Period events); Volcano-Tectonic (VT) earthquakes increased in late October after most of the monitored parameters reached their climax.
Afterwards, major episodes of VT activity were also recorded from March to April and at the end of the year 2022, when an earthquake of ML 4.6 occurred on December 4, SW of the island of Vulcano.
Here, we analyze the VT earthquakes from January 2020 to December 2022, in terms of space-time distribution, energy release and focal mechanisms in the framework of the regional geodynamic context and in the light of the main characteristics of the seismic activity recorded in the Vulcano area over the past 36 years.PublishedSan Francisco, California, USAOST3 Vicino alla fagli
Hydrogeochemical multi-component approach to assess fluids upwelling and mixing in shallow carbonate-evaporitic aquifers (Contursi area, southern Apennines, Italy)
No full textWith the aim of deepening our understanding of deep-seated fluids upwelling and mixing in large regional
aquifers, we performed a hydrogeochemical study of twenty-two springs in the Contursi area (upper Sele river
valley, southern Apennines) by means of the measurements of chemical-physical parameters, major ions, trace
elements, and stable and radioactive isotopes. Besides, we realized two updated geo-structural cross-sections inorder to reconstruct the groundwater flowpath in the study area. The hydrogeochemical composition, as well a the water temperature allow to identify-three main groups of groundwater: Cold and Low salinity Groundwater
(CLGW), Intermediate Salinity Groundwater (ISGW), and Thermal Salinity Groundwater (TSGW). The CLGW
group, mostly emerging at the boundary of carbonate aquifers, is characterized by alkaline earth-bicarbonate
hydrofacies. Instead, ISGW and TSGW, situated in the inner zone of the valley, show gradually a hydrogeochemical evolution towards sodium-chloride type hydrofacies domain with the highest salinity value. Stable isotope (δ18O-δD) of CLGW reveal the local meteoric origin of groundwater, while isotopic signatures of ISGW and TSGW is associated with the deep fluids inflow. CLGW hydrogeochemistry is clearly related to dissolution of carbonate rocks. On the other hand, for ISGW and TSGW an additional contribution from evaporitic rocks is supported by saturation indices values (gypsum and anhydrite) and validated by isotopic signature of dissolved sulphate (δ34S-δ18O). The application of two models based on tritium data (i.e., the piston-flow and well-mixed reservoir) attributes longer and deeper groundwater flowpaths to TSGW. Through geothermometric calculations (e,g., K-Mg and SiO2-quartz), the equilibrium temperature of deep fluids reservoir is also extrapolated (i.e., 75–96 ◦C). The results of the adopted hydrogeochemical multi-component approach allowed us to propose an interpretative model of groundwater flowpath for the Contursi area, where deep-seated tectonic discontinuities play a significant role for the upwelling of saline deep thermal fluids in shallow aquifers.Published1292589T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismicheJCR Journa
Palaeoenvironmental reconstruction of a lower to middle Permian terrestrial composite succession from the Catalan Pyrenees: Implications for the evolution of tetrapod ecosystems in equatorial Pangaea
No full textTetrapod diversity in Permian terrestrial ecosystems of southwestern Europe is poorly
recorded by bone specimens, but it is better represented by an important tetrapod ichnological
record that is relevant to our understanding of vertebrate communities in the equatorial
Pangaea. Herein, two tetrapod ichnoassociations from three new ichnosites, within Cisuralian
and Guadalupian volcanosedimentary terrestrial successions (the Lower Red Unit and the
Upper Red Unit deposits) of the Castellar de n’Hug sub-basin (Catalan Pyrenees, NE Iberian
Peninsula) are presented. Tetrapod ichnology in combination with stratigraphic and facies
analyses permit a characterisation of these ecosystems. The sedimentary deposits show an
evolution from fluvial meandering systems to playa-lake floodplains, denoting increased
aridification and seasonality under a monsoonal regime. The ichnofossil record shows how
tetrapod assemblages shifted from a prevalence of non-amniotes and eureptiles to a
dominance of therapsids, eureptiles and parareptiles. The reported ichnotaxa are distributed in
two ichnoassociations. The first preserves Batrachichnus, Dromopus, Hyloidichnus,
Characichnos and an indeterminate tetrapod morphotype, whereas the second is defined by
the presence of Dromopus, Hyloidichnus, Brontopus antecursor and Pachypes. The
stratigraphically older ichnoassociation, preserved in volcaniclastic and fluvial deposits,
presents features of the early Erpetopus biochron, whereas the stratigraphically younger one,
preserved in playa-lake deposits, is constrained to the Brontopus sub-biochron.
Biostratigraphic and magnetostratigraphic data suggest a late Cisuralian to middle
Guadalupian age for the whole succession. The ichnoassemblage highlights a
palaeobiogeographical connection between the Pyrenean Basin and other peri-Tethyan
basins, which allows us to expand our knowledge about the palaeoecology and
palaeobiodiversity of the Cisuralian to Guadalupian terrestrial ecosystems.Published111837OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa
Fault and Fluid Interaction during the 2012 Emilia (Northern Italy) Seismic Sequence
No full textThe triggering of large earthquakes by anthropic activities is a challenging issue in seis-
mology, invoked also for the M L 5.9 and 5.8 Emilia 2012 destructive earthquakes. The
interaction between the two earthquakes that propagated along adjacent thrusts is still
an open issue. In this study, we used waveform cross correlation and double-difference
(DD) location methods to precisely relocate the aftershock sequence and get insights into
fault geometry, structure, and rheology by means of DD seismic tomography. Accurate
relocations highlight a complex fault system with small-length fault segments coalescing
in the Mirandola and Ferrara thrusts. We observe a broad continuous high-V P = V S
anomaly at seismogenic depth (about 6.0 km) that suggests a possible hydraulic connec-
tion along the entire fault system. A close look at seismicity indicates a quasi-simultane-
ous activation of the entire thrust system, with the two mainshocks and large aftershocks
occurring within the high-V P = V S , high fluid pressure, and connecting volume.Published671–684OST3 Vicino alla fagliaJCR Journa
The Museum of the Osservatorio Vesuviano: inviting the public to explore the geoheritage of the world’s first volcano observatory
No full textThe Osservatorio Vesuviano (OV) is the oldest volcano observatory in the world having been founded in 1841 by the King of the Two Sicilies Ferdinand II of Bourbon. The historical building, located on the western slope of Vesuvius, hosts a museum with important collections of remarkable scientifc, historical and artistic value, including pioneering instruments, rocks and minerals, photos and flms of Vesuvius’ eruptions and many other memorabilia. Visitors discover this heritage through perma nent exhibitions, and a multimedia path, across the history of Vesuvius and the origin of volcano monitoring. The museum lies within the protected area of Vesuvius National Park, established in 1995. The park’s network of trails allows visitors to enjoy
the geodiversity of Somma-Vesuvius, whose activity has been intertwined with that of humans from Bronze Age to modern times, as testifed by many important archaeological sites around the volcano, the most famous among them being Pompeii and Herculaneum. The “Grand Tour” was the cultural journey undertaken in the eighteenth century by European intellectuals, in which Italy was an essential destination; we consider the Museum of the OV an essential stop in a modern “Vesuvius Grand Tour”, a journey through the geological and archaeological heritage of Vesuvius territory. Since 2001, the OV is the Naples section of the Istituto Nazionale di Geofsica e Vulcanologia (INGV), which is primarily tasked with monitoring the three active volcanoes of the Neapolitan area—Vesuvius, Campi Flegrei and Ischia—through an advanced surveillance networkPublished451V. Storia eruttiva6IT. Osservatori non satellitari2TM. Divulgazione Scientifica3TM. ComunicazioneJCR Journa
Dominant features and variability of the mesoscale circulation and thermohaline structure of the eastern Levantine during the post POEM period 1995-2015
No full textAn analysis of in-situ data gathered over the two decade post POEM period in the South-Eastern Levantine Basin from extensive hydrographic (CTD) campaigns and VOS XBT transects, along with data provided by the latest SeaDataCloud Mediterranean Sea Temperature and Salinity climatology (http://dx.doi.org/10.12770/3f8eaace-9f9b-4b1b-a7a4-9c55270e205a) and the Mediterranean Sea Physics Reanalysis from the Copernicus Marine Service (CMS; https://data.marine.copernicus.eu/product/MEDSEA_MULTIYEAR_PHY_006_004), have all provided insight on the dominant, coherent, meso-scale, circulation features as well as the evolution and variability of the thermohaline properties of the main water masses in this sub-basin. The most pronounced feature, the warm core Cyprus Eddy, migrates over the broad region of the Eratosthenes seamount and exhibits significant seasonal and inter-annual spatio-temporal variability. Another prominent structure is the anticyclonic Shikmona Eddy generated periodically due to instabilities of the strong northward flowing jet along the south-easternmost shelf and slope of the Levantine basin. Its evolution and co-existence with the Cyprus Eddy for periods of a few months, affects the temporal re-establishment of the Shikmona Gyre, which was first observed during the POEM cruises in the mid 1980s. The eastward flowing Mid Mediterranean Jet (MMJ) defines the northern flanks of these sub-basin scale eddies and transports the lower salinity Modified Atlantic Water (MAW) through the warmest and most saline region of the Mediterranean. Periodically the MMJ bifurcates and/or is diverted northward, along the western coast of Cyprus due to spatial fluctuations of the Cyprus Eddy. Four active periods were identified with either a dominant Cyprus Eddy only or coexisting Cyprus and Shikmona Eddies. This long term in-situ monitoring also provides an overview of the extent of the main water masses and characterizes their variability throughout the period considered. The temperature and salinity of the Levantine Surface Water (LSW) and of the subsurface MAW have increased. The Eastern Mediterranean Transient Water (EMTW) is shown to occupy the deep cavities, below the Eastern Mediterranean Deep Water (EMDW), in the vicinity of the Eratosthenes seamount while its upper boundary was lifted to shallower depths over the same period.PublishedViennaOSA4: Ambiente marino, fascia costiera ed Oceanografia operativ
Stepping Into an Equatorial Plasma Bubble With a Swarm Overfly
No full textESA's Swarm constellation entered in a “overfly” configuration in the period between September
and October 2021, when the longitudinal distance between the lower pair and the upper satellite was at its
minimum since the launch of the spacecrafts. In addition, the local time of the nighttime tracks was favorable
to detect and study the morphology of post-sunset equatorial plasma bubbles (EPBs). In this study, we focus
on the Swarm overfly occurring between 00:41 UT and 00:59 UT on 30 September 2021, which covered
one of the most densely instrumented regions for the study of the ionospheric irregularities embedded in
the EPBs: the South American sector. By exploiting the use of ground-based receivers of Global Navigation
Satellite System (GNSS) signals in combination with the Swarm plasma density measurements, we study the
irregularities in the EPB formed at ∼60°W and investigate the different scales of the irregularities and the
cascading processes along the magnetic flux tubes. We also highlight how diffusion along the magnetic field
lines occurs simultaneously with the plasma uplift, contributing then to the correct interpretation of the EPB
evolution and decay process. The precious overfly conditions also allow the introduction of ionosphere-related
quantities, evaluated across the tracks at satellite altitudes enlarging the possibilities given by the same
quantities already available along the tracks. Such opportunity envisages the possibility to proxy the impact of
EPBs on GNSS signals with Low-Earth Orbit satellite data provided by future missions specifically dedicated
to the characterization of the near-Earth environment and ionospheric studies.Publishede2022SW003331OSA3: Climatologia e meteorologia spazialeJCR Journa
An investigation of high frequency seismic tremor on Mt Etna
No full textHigh frequency seismic data (> 10 Hz) on volcanoes have traditionally been less studied as precursory seismicity to volcanic eruptions is dominated by lower frequency signals. However, inspection of newly acquired data during a field campaign between July and September 2022 from individual high sampling rate seismic stations on Mt. Etna reveals the presence of high frequency (10-90Hz) signals, which are poorly understood. In an attempt to determine their location, mechanisms and wavefield properties, we deployed 104 nodal seismic sensors, mainly in 6 tuned circular array configurations consisting of several rings with increasing radius and number of nodes per ring around a central station. The nodes record at a sampling rate of 250Hz (125Hz Nyquist) and the frequency content of the recorded seismicity shows signals up to about 100 Hz. In addition to the high frequency nodes, we also deployed a profile consisting of 11 elements (infrasound, short period) as well as four broad band sensors.A variety of signals were recorded, with coherent signals on different stations across the full spectral range. Thus far initial multi-array beamforming has been applied to the data, demonstrating a range of locations which varies depending on the frequency range looked at. Whilst sources near the summit region are most common (especially at frequencies below 5 Hz), there are also other locations from which tremor emanates, opening questions about their origin. Comparisons with infrasound, gas and weather data are ongoing, in an effort to shed light on the sources of these unusual signals.PublishedViennaOSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametric
Bollettino Sismico Italiano gennaio – aprile 2022
No full textLa revisione da parte degli analisti del BSI della sismicità registrata in Italia dal 1 gennaio al 30 aprile 2022 ha riguardato tutti i terremoti di magnitudo ML≥1.5, mentre i parametri dei terremoti di magnitudo inferiore a tale soglia sono quelli calcolati in tempo reale, nella SALA DI SORVEGLIANZA SISMICA DI ROMA. I terremoti più forti (ML≥3.5), e pochi altri di particolare interesse [vedi Marchetti et al., 2016, DOI: 10.4401/ag- 6116], sono stati revisionati dagli analisti del BSI, mediamente nelle 24 ore successive al loro accadimento.Istituto Nazionale di Geofisica e Vulcanologia - Dipartimento di Protezione CivilePublishedOST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impatt