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Co-Ordinated Observations of Multi-Scale Irregularities Using ICEBEAR and GNSS During the May 2024 Superstorm
No full textWe present observations of plasma structuring from three meters up to hundreds of kilometers at auroral latitudes during the extreme geomagnetic storm of May 2024 using coordinated observations from ICEBEAR and Global Navigation Satellite Systems (GNSS) receivers. Intense irregularities on all spatial scales co-existed for about 4 hr between ∼ 63° 68°magnetic latitudes on 10 May during the storm's expansion phase when dense plasma structures and particle precipitation were simultaneously present at the dayside. Irregularities with scales of the order of few hundred meters remained weak thereafter following the depletion of the high latitude ionosphere even though particle precipitation was still ongoing. On the other hand, three meter E-region irregularities and kilometer scale gradients persisted for about 24 hr, suggesting that both dayside and nightside auroral dynamics contributed to their sustained production. With the absence of an enhanced density reservoir and the region of particle precipitation shifted to higher latitudes, we observed a significant depletion in the irregularity occurrence across all scales in the dayside auroral region on 11 May.PublishedJCR Journa
Thermal transient PDC behavior induced by topographic drops: A test case at Mt. St. Helens, USA
No full textPublishe
Pressurized magma storage in radial dike network beneath Etna volcano evidenced with P-wave anisotropic imaging
No full textInvestigating crustal stress beneath volcanoes is critical to understanding the dynamics of eruptions. To this end, seismology represents a powerful monitoring tool. The opening of fluid-filled fractures due to the interplay of different stress sources produces elastic anisotropy within the crust, affecting the propagation of seismic waves. Here we use probabilistic imaging for the inversion of P-wave travel times to map elastic anisotropy of the magmatic system beneath Mt. Etna (Italy). These images provide localized information about fracture orientations and stress below this active volcano. Comparing inferred stress with independent observations and geodynamic modeling, we show evidence of a pressurized magma storage in a radial dike network between 6 and 16 km depth under the volcano. The radial network of vertical dikes constitutes a system of oriented pathways for the upward migration of magma from the depths, leading to eruptive activity from the summit craters and lateral vents at Mount Etna.PublishedJCR Journa
Hydrogeological and structural controls on radon concentration in aquifers from alluvial areas: A case study of the Pordenonese plain (NE Italy)
No full textThis study aims to investigate the complex relationship between hydrogeological processes and tectonic structures which influence the spatial distribution of radon within alluvial aquifers in the Pordenonese Plain (PP). The results suggest that the source of dissolved 222 Rn is primarily linked to the intrinsic radioactivity of plain's sediments. Seasonal fluctuations in radon concentrations, which are closely related to recharge inputs into aquifers, have been observed for shallower unconfined and semi-confined aquifers, (i.e., those responding rapidly to meteoric inputs), while no significant variations have been observed in the deeper confined aquifers. Meteoric recharge leads to a dilution effect, thereby reducing radon concentrations during periods of increased precipitation. The spatial distribution of dissolved 222 Rn shows a correlation between anomalous concentrations and the seismogenic structures crossing the study area, i.e. the Polcenigo-Maniago Thrust Fault (PMTF), the Cansiglio Thrust Fault (CTF), and the Vigonovo Thrust Fault (VTF), suggesting that the fracture network likely plays an important role in favouring its migration. This work establishes the baseline for 222 Rn concentrations in the sedimentary aquifers of the PP, while also illustrating the role of climatic factors in their variability. The findings provide valuable insights for future multidisciplinary monitoring efforts, enhancing the understanding of tectonic processes in the PP and contributing to the development of more effective seismic risk management strategies.PublishedJCR Journa
Deformation and morphological changes before the 2021–2022 explosive eruption at Hunga Tonga-Hunga Ha’apai submarine caldera revealed by satellite remote sensing
No full textOn December 19, 2021, the Hunga Tonga-Hunga Ha'apai (HTHH) submarine volcano in the Tonga-Kermadec island arc initiated a new eruptive phase that lasted for approximately 1 month after 7 years of dormancy. This eruptive phase culminated in the January 15, 2022, VEI ≈ 6, Plinian eruption and the associated destructive tsunami. To analyze the complete eruption sequence of the HTHH volcano from 2021 to 2022 and to relate it to the previous eruptions, satellite optical images and synthetic aperture radar images are analyzed revealing the morphological changes of the volcanic island(s) during the time. The preparatory phase preceding the first eruption on December 19, 2021, is studied by considering descending Sentinel-1A images from 2020 to 2021. The obtained surface deformation of the HTHH volcano before the December 2021 eruption shows an up to nearly 6.4 cm on the line of sight. Results reveal that a possible intrusion of magma started in May 2020 and gradually increased until December 2021, leading to a 19-month long deformation phase before the eruption. The observed deformation is possibly explained by (a) a NNW-SSE striking, magma-filled dike upraising since the beginning of 2020 from a 5-km-deep spheroid-like source located at 5000 m depth, i.e., the magma chamber, and (b) gravity instability phenomena along the flanks of the tuff cones. Our study highlights the relevance of satellite monitoring of small volcanic islands resenting the top or caldera rims of larger submarine volcanoes. The capability to analyze the deformation of such small islands may provide valuable information for the detection of unrest episodes.PublishedJCR Journa
Detecting in situ directional discontinuities in the Solar Wind at Mercury’s orbit
No full textPublishedOSA3: Climatologia e meteorologia spazialeJCR Journa
Real-time GPS vs full-GNSS time series accuracies estimations at RING INGV research infrastructure
No full textThe RING (Rete Integrata Nazionale GNSS) is a research infrastructure developed for accurately measuring deformations at different spatial and temporal scales in the Eurasia-Africa plate boundary region (Avallone et al., 2010). Currently, the RING network (http://ring.gm.ingv.it/) is composed of 280 real-time transmitting remote sites, 70% of which are now equipped with full-GNSS (GPS, Galileo, Glonass and Beidou) instrumentation. The data streaming, in standard RTCM v.3 format, from these sites to the acquisition centre in southern Italy (Sezione Irpinia, Grottaminarda, AV) is managed by a tuned Ntrip Caster (https://igs.bkg.bund.de/ntrip/bkgcaster).
The typical magnitude of the strongest events that occurred in the last century in this region (5.5-7) should require high accuracy (2-3 cm) GPS/GNSS time series to properly observe both static and dynamic coseismic displacements and, then, to properly model the earthquake source. Furthermore, the detection of any afterslip or, in general, any transient deformation should require even better accuracy (< 2 cm). The real-time GPS/GNSS data analysis has been implemented by means of the RTPPP software developed by GFZ (Ge et al., 2012). This software allows the determination of various Precise Point Positioning products with increasing accuracy (standard PPP, PPP with ambiguity resolution [PPP-AR], and PPP with regional augmentation [PPP-RA]). We performed some preliminary investigations on different (limited in time) datasets and we compared GPS-only and full-GNSS results. In the case of GPS-only PPP-RA solutions, the accuracies estimated on 24-hour data for the whole network amount up to 1.7 cm and 6 cm for the horizontal and vertical components, respectively. In the case of full-GNSS solutions, the same approach (PPP-RA) allowed an improvement of about 22% on both horizontal and vertical components (1.3 cm and 4.6 cm). Furthermore, we compared both GPS-only and full-GNSS solutions with another method, i.e. by using a short-term accuracy analysis. Using 60-s or 120-s sliding windows, that should better simulate the time span for detecting coseismic displacements, we can achieve 0.5 cm and 1 cm for horizontal and vertical components, respectively, for GPS-only solutions, and 0.3 cm and 0.5 cm for full-GNSS ones.
Finally, for a few examples of earthquakes that recently occurred in Italy, we will show comparisons between post processed high-rate solutions carried out by Gipsy-Oasis II solutions and those obtained by RTPPP simulating real-time time series. The obtained accuracies will demonstrate the reliability of the RING infrastructure real-time GNSS solutions for early warning and rapid response applications.Publishe
Modeling tsunami generation and propagation: Insights from sensitivity analysis of landslide parameters at Stromboli
No full textPublishe
Shallow Submarine CO 2 Emissions in Coastal Volcanic Areas Implication for Global Carbon Budget Estimates: The Case of Vulcano Island (Italy)
No full textThe Earth’s degassing is an important factor in evaluating global carbon budget estimates and understanding the carbon cycle. As a result, numerous studies have focused on this topic. However, current estimates predominantly focus on subaerial CO2 emissions and CO2 deep submarine emissions, particularly along mid-ocean ridges (MORs), whereas very few and only spatially limited estimates of shallow submarine CO2 emissions have been reported, despite being widespread features of the seafloor. This study reports the results of measuring the dissolved CO2 concentrations in shallow submarine environments along the coast of Vulcano Island (Aeolian Islands, Italy). For the areas exhibiting the highest concentrations, we calculated the amount of diffuse degassing by computing the sea–air CO2 flux. The results revealed extremely high dissolved CO2 concentrations, reaching up to 24 vol.% in areas with visible hydrothermal activity, including one location far from the island’s main crater. Notably, elevated CO2 levels were also detected in areas with minimal or no apparent hydrothermal discharge, indicating the occurrence of diffuse degassing processes in these areas. In addition, the calculated diffuse degassing flux was comparable in magnitude to the CO2 flux directly emitted into the atmosphere from the island’s main bubbling pools.PublishedOSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
Scintillations in Southern Europe During the Geomagnetic Storm of June 2015
No full textThis article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) licensePublishedJCR Journa