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Cryptotephras in the marine sediment record of the Edisto Inlet, Ross Sea: Implications for the volcanology and tephrochronology of northern Victoria Land, Antarctica
No full textWe present the results of the tephrochronology study of a 14.49 m long marine sediment core (TR 17–08) collected in the Edisto Inlet, Ross Sea (Antarctica). The core contains four cryptotephra layers at 55–56, 512–513, 517–518, and 524–525 cm of depth, which have been characterised by a detailed description of the texture, mineral assemblage, and single glass shards major and trace element geochemistry. The age model of the investigated sedimentary sequence, based on radiocarbon dating, indicates that the topmost cryptotephra correlates with the widespread 1254 CE tephra erupted by a historical eruption (696 ± 2 cal yrs BP) of Mount Rittmann, in northern Victoria Land. Deeper cryptotephra layers were derived from previously unknown explosive eruptions of Mount Melbourne volcano and were emplaced between 1615 cal yrs BP and 1677 cal yrs BP, e.g. between the 3rd and 4th centuries CE. This discovery demonstrates that the Mount Melbourne volcanic complex has been highly active in historical times allowing significant progress in the current understanding of regional eruptive history. Moreover, from a tephrochronological point of view, the detected cryptotephra provide new regional isochron markers to facilitate high-precision correlations and help stratigraphically constrain changes in environmental and climatic conditions that are identified by multidisciplinary studies.Published100079OSA3: Climatologia e meteorologia spazialeJCR Journa
Status of the GINGER project
No full textLarge frame ring laser gyroscopes, based on the Sagnac effect, are top sensitivity instrumentation to measure angular velocity with respect to
the fixed stars. GINGER (Gyroscopes IN GEneral Relativity) project foresees the construction of an array of three large dimension ring laser
gyroscopes, rigidly connected to the Earth. GINGER has the potentiality to measure general relativity effects and Lorentz Violation in the
gravity sector, once a sensitivity of 10 9, or better, of the Earth rotation rate is obtained. Being attached to the Earth crust, the array will also
provide useful data for geophysical investigation. For this purpose, it is at present under construction as part of the multi-components observatory
called Underground Geophysics at Gran Sasso (UGSS). Sensitivity is the key point to determine the relevance of this instrument for
fundamental science. The most recent progress in the sensitivity measurement, obtained on a ring laser prototype called GINGERINO, indicates
that GINGER should reach the level of 1 part in 1011 of the Earth rotation rate.Published045001OST5 Verso un nuovo MonitoraggioJCR Journa
Active fault detection and characterization by ultrashallow seismic imaging: A case study from the 2016 Mw 6.5 central Italy earthquake
No full textWe present the first high-resolution ultrashallow seismic image of a normal fault segment that ruptured the surface during the Mw 6.5 2016 Norcia earthquake (central Italy). This is the only fault, in the entire activated 25 km-long system, cutting a thick succession of Quaternary deposits, with an associated 3-m-high cumulative scarp. A 190-m-long profile crossing the fault was acquired and analyzed combining reflection seismic, non-linear multiscale refraction P-wave tomography and multi-channel analysis of surface waves. The joint interpretation of the seismic reflection, P- and S-wave velocity images unravels a 100-m-thick sequence of sandy-gravel alluvial fans, disrupted by a main normal fault zone, named as Valle delle Fonti fault (Vf1), which branches upward into three splays. The eastern splay of Vf1 matches with the 2016 coseismic surface rupture. Near-surface truncated reflections and growth strata in the hanging wall of the western and intermediate splays attest to their activity in Late Pleistocene-Holocene times. We also detect an additional normal fault in the footwall of Vf1, probably inactive since the Late Pleistocene.
Comparing the seismic images with the Poisson's coefficient model and with the results of a previous electrical resistivity tomography, we constrain the lithology and the hydraulic behavior of the uppermost 50 m of the fault. A steep, W-dipping zone with high-Vp, very high Poisson's coefficient and low resistivity correlates with the eastern splay of Valle delle Fonti fault and unravels a water-saturated region. These results suggest that the fault zone may act as a partial barrier for horizontal fluid flow. Our findings indicate that the active fault zone detected by seismic imaging is much wider than what previously estimated from surface geological analyses. In terms of surface faulting hazard, this study confirms the effectiveness of high-resolution seismic surveys in defining the geometry and physical properties of active fault zones.Published229733OST3 Vicino alla fagliaOSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa
Towards a crustal structure investigation in the area of Mefite d’Ansanto (Italy) by using equalised teleseismic waveforms
No full textWe propose and test a procedure in the time domain to directly compare the waveforms of teleseismic events recorded by seismic stations located a few kilometres from each other and equipped with different instrumentations. The method is based on the deconvolution of the signals at each seismic station for its sensor own frequency response and data sampling to equalise the waveforms, making them directly comparable. The
horizontal components of the events are rotated versus back-azimuth, considering that P-to-S converted phases along a crustal discontinuity are generally more evident in the radial and transverse components. Finally, we apply the cross-correlation technique to the resulting signals to quantify the similarities among the waveforms. The method has been tested on teleseismic events recorded by the seismic stations located in and close to the Mefite d’Ansanto area (southern Apennines), which represents the largest non-volcanic low temperature CO2 emission area on Earth.Published405-416JCR Journa
Dynamics of Magma Chamber Replenishment Under Buoyancy and Pressure Forces
No full textActive magma chambers are periodically replenished upon a combination of buoyancy and pressure forces driving upward motion of initially deep magma. Such periodic replenishments concur to determine the chemical evolution of shallow magmas, they are often associated to volcanic unrests, and they are nearly ubiquitously found to shortly precede a volcanic eruption. Here we numerically simulate the dynamics of shallow magma chamber replenishment by systematically investigating the roles of buoyancy and pressure forces, from pure buoyancy to pure pressure conditions and across combinations of them. Our numerical results refer to volcanic systems that are not frequently erupting, for which magma at shallow level is isolated from the surface (â\euroœclosed conduitâ\euro? volcanoes). The results depict a variety of dynamic evolutions, with the pure buoyant end-member associated with effective convection and mixing and generation of no or negative overpressure in the shallow chamber, and the pure pressure end-member translating into effective shallow pressure increase without any dynamics of magma convection associated. Mixed conditions with variable extents of buoyancy and pressure forces illustrate dynamics initially dominated by overpressure, then, over the longer term, by buoyancy forces. Results globally suggest that many shallow magmatic systems may evolve during their lifetime under the control of buoyancy forces, likely triggered by shallow magma degassing. That naturally leads to long-term stable dynamic conditions characterized by periodic replenishments of partially degassed, heavier magma by volatile-rich fresh deep magma, similar to those reconstructed from petrology of many shallow-emplaced magmatic bodies.Publishede2022JB0253164V. Processi pre-eruttiviJCR Journa
The CAESAR Project for the ASI Space Weather Infrastructure
No full textThis paper presents the project Comprehensive spAce wEather Studies for the ASPIS prototype Realization (CAESAR), which aims to tackle the relevant aspects of Space Weather (SWE) science and develop a prototype of the scientific data centre for Space Weather of the Italian Space Agency (ASI) called ASPIS (ASI SPace Weather InfraStructure). To this end, CAESAR involves the majority of the SWE Italian community, bringing together 10 Italian institutions as partners, and a total of 92 researchers. The CAESAR approach encompasses the whole chain of phenomena from the Sun to Earth up to planetary environments in a multidisciplinary, comprehensive, and unprecedented way. Detailed and integrated studies are being performed on a number of well-observed “target SWE events”, which exhibit noticeable SWE characteristics from several SWE perspectives. CAESAR investigations synergistically exploit a great variety of different products (datasets, codes, models), both long-standing and novel, that will be made available in the ASPIS prototype: this will consist of a relational database (DB), an interface, and a wiki-like documentation structure. The DB will be accessed through both a Web graphical interface and the ASPIS.py module, i.e., a library of functions in Python, which will be available for download and installation. The ASPIS prototype will unify multiple SWE resources through a flexible and adaptable architecture, and will integrate currently available international SWE assets to foster scientific studies and advance forecasting capabilities.Published3461A. Geomagnetismo e Paleomagnetismo2A. Fisica dell'alta atmosferaJCR Journa
Ambient Noise Tomography of the Lipari Volcanic Island (Southern Italy) From a Dense Nodal Array
No full textWe applied ambient noise tomography to continuous data recorded by a dense seismic array
deployed on the volcanic island of Lipari in the southern Tyrrhenian Sea. Since most of Lipari's seismicity
occurs offshore and is not evenly distributed, this technique allowed us to obtain the first high-resolution images
beneath the island down to ∼2.5 km depth. Results show a complex seismic structure related to the various ages
and compositions of the volcanic products characteristic of the different regions of the island. High shear wave
velocities are found in western Lipari, where active hydrothermal vents and N-S faults are mapped. Low wave
speeds are revealed beneath southern and northeastern Lipari, where more recent volcanic activity developed
along N-S dike-like structures that are aligned with rhyolitic vents. We suggest these dikes likely represent the
probable pathways of future volcanic eruptions.Publishede2022GL101022OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàJCR Journa
Influence of Fault System Geometry and Slip Rates on the Relative Role of Coseismic and Interseismic Stresses on Earthquake Triggering and Recurrence Variability
No full textWe model Coulomb stress transfer (CST) due to 30 strong earthquakes occurring on normal faults since 1509 CE in Calabria, Italy, including the influence of interseismic loading, and compare the results to existing studies of stress interaction from the Central and Southern Apennines, Italy. The three normal fault systems have different geometries and long-term slip-rates. We investigate the extent to which stress transfer can influence the occurrence of future earthquakes and what factors may govern the variability in earthquake recurrence in different fault systems. The Calabrian, Central Apennines, and Southern Apennines fault systems have 91%, 73%, and 70% of faults with mean positive cumulative CST in the time considered; this is due to fewer faults across strike, more across strike stress reductions, and greater along-strike spacing in the three regions respectively. In regions with close along strike spacing or few faults across strike, such as Calabria and Southern Apennines, the stress loading history is mostly dominated by interseismic loading and most faults are positively stressed before an earthquake occur on them (96% of all faults that ruptured in Calabria; 94% of faults in Southern Apennines), and some of the strongest earthquakes occur on faults with the highest mean cumulative stress of all faults prior to the earthquake. In the Central Apennines, where across strike interactions are the predominant process, 79% of earthquakes occur on faults positively stressed. The results highlight that fault system geometry plays a central role in characterizing the stress evolution associated with earthquake recurrence.This work was supported by a Natural Environment Research Council studentship (Grant NE/L002485/1) to Claudia Sgambato. Original development of the 3D-faults code was supported by NERC PhD Studentship NE/L501700/1 and JSPS Short Term Fellowship PE15776 to Zoë Mildon.Publishede2023JB026496OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
HERMES: A Data and Specimens Transporter from the Stratosphere to the Ground—The First Experimental Flight
No full textLarge stratospheric balloons are the easiest access to near space. Large long duration balloons
(LDBs) can float in the stratosphere for weeks collecting measurements (e.g., astrophysical
or geophysical data) or samples (e.g., contaminants, volcanic ash, micrometeorites). The recovery
of data media and samples is a common problem in this type of experiment because direct radio
com-munication becomes useless when the balloon crosses the horizon, and satellite links are too
slow and expensive. For this reason, physical recovery of the payload is mandatory to obtain
experi-mental results, which is a difficult task, especially in polar regions. The goal of HERMES
(HEmera Returning MESsenger) is to allow researchers to obtain experimental data prior to
payload recovery. HERMES is a system equipped with an autonomous glider capable of
physically transporting data and samples from the stratosphere to a recovery point on the ground.
The glider is installed on the balloon payload via a remotely controlled release system and is
connected to the main computer to store a copy of the scientific data and to receive the geographic
coordinates of the recovery point. This allows scientists to obtain experimental results before
recovering the payload. The article de-scribes HERMES and the first experimental flight of the
entire system, which was conducted at Esrange Space Center (Kiruna, Sweden) in July 2022.Published308JCR Journa
Vulnerability Assessment of Art Collections: The National Archaeological Museum “Gaio Cilnio Mecenate” in Arezzo (Italy)
No full textArtworks play a fundamental role in the cultural and economic assets of communities, enhancing their identity and helping with social integration. Despite their importance, they are not always adequately protected against degradation, which can be induced by aging, atmospheric and human-induced occurrences, and catastrophic events. Earthquakes certainly represent one of the main risks for art objects; however, traffic, construction works, and shipment can also represent a threat to art goods. Therefore, the assessment of the vulnerability of art collections to dynamic excitations plays a crucial role in their conservation, and it has been collecting increasing attention from researchers, academics, and museum managers. This work focuses on the vulnerability of the art collections exhibited at the “Gaio Cilnio Mecenate” museum in Arezzo. Namely, it aims to assess the effective dynamic loading experienced by the artworks, which is a function of the dynamic propagation played by the foundation soil, the building, and the displayers used for the exhibition. In this study, the dynamic properties of some of the displayers used for exhibiting the art collections are investigated by performing an experimental survey. The analysis of the experimental data led to the assessment of the proper frequencies of the displayers, which were compared to those of the building and the foundation soil of the museum.Published2701JCR Journa