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Flow front mobility of rock avalanches as a function of flow volume, grain size, channel width, basal friction and flow scale
No full textThe ability to predict the mobility of rock avalanches is necessary when designing strategies to mitigate the risks they pose. A popular mobility indicator of the flow front is the Heim’s apparent friction coefficient muH. In the field, muH shows a decrease in value as flow volume V increases. But this correlation has been a mystery as to whether it is due to a causal relationship between V and mobility since: (1) field data of muH do not collapse onto a single curve because typically widely scattered and (2) laboratory experiments have shown an opposite volume effect on the center of mass mobility of miniature flows. My numerical simulations confirm for the first time the existence of a functional relationship of scaling parameters where muH decreases as V increases in unsteady and nonuniform 3D flows. Data scatter is caused by muH that is affected by numerous other variables besides V. The interplay of these variables produces different granular regimes with opposite volume effects. In particular,
muH decreases as V increases in the regime characterized by a relatively rough subsurface. The relationship holds for large-scale flows that, like rock avalanches, consist of a very large number of fine clasts traveling in wide channels. In these dense flows, flow front mobility increases as flow volume increases, as channel width increases, as grain size decreases, as basal friction decreases and as flow scale increases. Larger-scale flows are more mobile because they have larger Froude number values.Published933–947OSV1: Verso la previsione dei fenomeni vulcanici pericolosiJCR Journa
Cross-Correlation among Seismic Events, Rainfalls, and Carbon Dioxide Anomalies in Spring Water: Insights from Geochemical Monitoring in Northern Tuscany, Italy
No full textVariations in the CO2 dissolved in water springs have long been observed near the epicenters of moderate and strong earthquakes. In a recent work focused on data collected during the
2017–2021 period from a monitoring site in the Northern Apennines, Italy, we noticed a significant
correlation between CO2 anomalies and moderate-to-weak seismic activity. Here, we extended this
analysis by focusing on data collected from the same site during a different period (2010–2013) and
by integrating the CENSUS method with an artificial neural network (ANN) in the already-tested
protocol. As in our previous work, a fit of the computed residual CO2 distributions allowed us to
evidence statistically relevant CO2 anomalies. Thus, we extended a test of the linear dependence
of these anomalies to seismic events over a longer period by means of binary correlations. This
new analysis also included strong seismic events. Depending on the method applied, we observed
different time lags. Specifically, using the CENSUS methodology, we detected a CO2 anomaly one
day ahead of the earthquake and another anomaly eleven days ahead. However, no anomaly was
observed with the ANN methodology. We also investigated possible correlations between CO2
concentrations and rain events and between rain events and earthquakes, highlighting the occurrence
of a CO2 anomaly one day after a rain event of at least 10 mm and no linear dependence of seismic
and rain events. Similar to our previous work, we achieved a probability gain of around 4, which is
the probably of earthquake increases after CO2 anomaly observations.Published739OST3 Vicino alla fagliaJCR Journa
Dual-Polarimetric SAR Measurements to Emphasize Liquefaction Surface Manifestations
No full textThis study is to discuss the ability of dual-polarimetric Sentinel-1 Synthetic Aperture Radar (SAR) measurements to observe surface liquefaction occurring during earthquakes. A polarimetric bi-temporal approach is proposed that, combining pre-and co-event SAR imagery, is able to emphasize areas affected by surface liquefaction. The approach is verified using Sentinel-1 SAR scenes related to the Turkey-Syria earthquake occurred in February 2023. The approach is shown to be effective in marking areas where surface liquefaction occurred.Publishe
In situ investigation of the atomic structure of carbonate-silicate liquids at high pressure-temperature and spectroscopic characterization of the recovered quenched glasses
No full textCarbonate-silicate melts that originate in Earth’s interior are described as transitional melts which possess
compositions intermediate between carbonatitic and basaltic end members. The covariation of key oxides between
carbonatite and basalt (e.g., 10–35 wt% SiO2 and 40–10 wt% CO2, respectively) is expected to have a
strong effect on liquid properties. However, due to their paucity both in the record of terrestrial rocks and as
quenched glasses, their molecular structure has remained poorly explored to date. We investigated the atomic
structure of a synthetic carbonate-silicate liquid with chemical composition within the CaO-MgO-Al2O3-SiO2-
FeO-Na2O-ClO -CO2 oxide system having 18.28 wt% SiO2 and 22.54 wt% CO2 using multi-angle energy
dispersive X-ray diffraction at pressures (P) and temperatures (T) of 1.4 GPa/1815 ◦C, 2.6 GPa/1865 ◦C, 4.3 GPa/
1990 ◦C, 4.4 GPa/1950 ◦C. The results show that the intermediate range ordering of the structure decreases with
an increase of both P and T. Based on this study, the carbonate-silicate magmas at upper mantle P-T conditions
are expected to increase their viscosities during their ascent through the mantle as a result of increasing intermediate
range ordering upon cooling and decompression. Additionally, spectroscopic measurements were carried
out on the quenched glasses at ambient pressure using micro-Raman as well as micro-FTIR in reflection and
transmission modes in the mid infrared range. High pressure investigation using micro-FTIR was also conducted.
The distribution of Qn species obtained by deconvolution of the Raman spectra within the aluminosilicate region
confirms the depolymerized nature of the quenched glasses as inferred by the low viscosities of the corresponding
liquids; peculiar characteristics of the C vibrations would suggest a distorted environment surrounding the
network modifying CO2/3- anion. No evidence of molecular CO2 was detected. Notably, we find evidence of both
dissolved molecular CO and CO linked to a metal cation forming carbonyl complexes in the quenched glasses at
P-T-fo2 conditions compatible with a hot Archean upper mantle. This suggests a role for carbonate-silicate
magmas as carriers of reduced gaseous C-O-H species towards the early atmosphere along with the mobilization
of PGE-elements.Published122152JCR Journa
Geohazard features of the Gulf of Naples and Pontine Islands (Eastern Tyrrhenian Sea)
No full textIn this paper, we describe the geohazard-related elements of the Eastern Tyrrhenian Sea continental margin, situated between the 40° and 41° North latitude. These features were recognised principally through morphological analysis. The investigation utilized medium – and high-resolution digital models of the submarine landscape, produced within the framework of the Magic project (Marine Geohazard along Italian Coasts), and primarily focusing on the bathymetric range of 50–700 meters. The surveyed area encompasses a recently formed continental margin, which connects the internal segments of the Apennine fold-and-thrust belt, verging NE, to the Tyrrhenian Sea bathyal plain, a 3000-m-deep back-arc basin that has developed since the Middle-Late Miocene. Several classes of hazard-related elements have been identified offshore, primarily associated with high-gradient slopes and a large number of volcanic edifices and banks. These include canyon systems, erosive scarps, landslide complexes, fault – and volcanic-related features, such as the products of the volcanic edifices instability, which claim to varying degrees of geo-hazard. Additionally, bedforms, fluid seepages and creeping phenomena in the prodelta slopes suggest high morpho-tectonic and environmental dynamics.Published2378935JCR Journa
New insights from plumbing system below composite mafic volcanoes: Post-glacial volatile contents and magmatic fluids from Villarrica magmas
No full textVillarrica volcano, in the southern Andes, is a composite mafic volcano whose persistent open-vent activity is
punctuated by frequent Strombolian/Hawaiian eruptions and, more rarely, by more energetic (sub-Plinian)
events. Here, we investigate the volatile composition of the parental melts that sustain this activity, and the
conditions of pre-eruptive magma storage, by characterizing the composition of olivine-hosted melt and fluid
inclusions. We concentrate on inclusions entrapped in minerals from pyroclastic materials erupted from both
Villarrica summit and from its flank Minor Eruptive Centers (MECs) post the 14.5–13.5 kyr caldera collapse event
that formed the Lic´an ignimbrite. Our micro-FTIR and SIMS measurements indicate that the Puc´on eruption
records the highest volatile contents, with 6.0 wt% H2O, >1500 ppm CO2, 1330 ppm S, 1556 ppm Cl, and 2055
ppm F. These volatile contents imply a volatile-saturated magma originating from a depth of 14.4 to 17 km below
Villarrica. Results for other flank eruptions highlight a similarly deep (17–21 km depth) source for basaltic CO2-
rich mafic magmas erupted at regional MECs (Los Nevados, Caburgua). Melt inclusion results also reveal that
deep rising mafic magma batches, when temporarily stored at 1–5 km depth, produce the more differentiated and
degassed magma batches that sustain the decadal-old persistent effusive-explosive eruptive activity at Villarrica.
Helium isotope ratios (3He/4He; Rc/Ra when corrected for atmosphere) measured in bulk noble gases from
olivines (Fo75–88) indicate that the parental magmatic fluid signature (Rc/Ra = 6.7–7.6; CO2/3He = 4.7–7.5E+08)
is only recorded during central paroxysmal sub-Plinian eruption, and that this primitive gas signal is diluted in
lateral MECs (Rc/Ra < 6.5; CO2/3He = 1.4 × 10+9–3.1E+10).Published107786JCR Journa
CO2 flux from the French Massif Central groundwaters: Modelling and quantitative estimation of the degassing process
No full textPassive rift systems are often characterized by CO 2 degassing, witnessed by the presence of mineral and thermal springs, bubbling pools, mofetes. Despite these field manifestations, the quantitative estimation of the CO 2 budget released to the atmosphere from these geodynamic structures is not well constrained. Here, we examine the chemistry of 169 springs, the isotopic composition of the dissolved carbon (δ 13 C TDIC) of 33 springs and the dissolved gases composition of 6 springs from the French Massif Central, part of the European Cenozoic Rift System (ECRIS), in order to describe the CO 2 degassing process and to compute the CO 2 emission rate released from groundwaters at regional scale. Water-gas-rock models reveal that the separation of gas from the liquid phase occurs at P-T conditions between 10 bar-180 • C and 1 bar-10 • C. The carbon mass and isotopic balance of spring waters of the French Massif Central allow us to compute a total deeply-sourced CO 2 emission rate of 1.52 ± 0.14 × 10 9 mol yr − 1 , suggesting that the CO 2 release from passive rift systems is significant at global scale and should be considered in the present-day global Earth degassing budget. The comparison of our data to other continental rift systems shows a high variability of CO 2 emission rates, highlighting that more detailed studies are needed to constrain the CO 2 flux from this geodynamic setting that, at present, is likely underestimated.Published122012JCR Journa
Active faults of the Jiloca basin (Central-eastern Iberian Chain - Spain): Geological mapping and morphotectonic analysis.
No full textThis thesis presents a morphotectonic and geological analysis of active faults within the Jiloca Basin, located in the central-eastern section of the Iberian Chain, Spain. The study addresses the need to characterize recent tectonic activity in an intraplate region. The primary objective was to produce an updated geological map of the Villar del Salz area, identify Quaternary active faults, and evaluate a new method for classifying erosional surfaces based on Schmidt hammer rebound measurements.
The methodology involved the interpretation of aerial photographs, field validation, detailed geological mapping, and structural analysis of the faults. The collected data were processed using Geographic Information System (GIS) software, such as QGIS for morphotectonic analysis and the creation of topographic profiles, and Stereonet for structural analysis.
The results enabled the creation of a detailed morphotectonic map of the erosional surfaces (FES) and extensional faults. Vertical throw estimations of the faults, quantified in a range of 10-150 meters, revealed a net slip rate between 0.01 and 0.04 mm/year. An atypical Quaternary fault with a WNW-ESE orientation, different from the prevailing systems, was identified, showing a maximum throw of approximately 120 meters in its central part. The analysis of rock hardness indicated a potential variability related to the operator.
In conclusion, this work provides a scientific contribution to the understanding of the morphostructure of the western margin of the Jiloca extensional basin. The results confirm that the dominant crustal deformation in the region is characterized by radial extension, with faults showing significant throws during the Plio-Quaternary.Università degli Studi dell'Insubria - Dipartimento di Scienze e Alta Tecnologia
Universidad de Zaragoza - Departamento de Ciencias de la TierraUnpublishe
When the Past Teaches the Future: Earthquake and Tsunami Risk Reduction through Episodes of Situated Learning (ESL)
No full textThe past offers important lessons with regard to facing the future with greater awareness. In
this context, school plays a key role in spreading knowledge of natural phenomena and in promoting
behavior change. Together with researchers, teachers can be strong allies to build more resilient
future citizens. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) school training activities
provide tools to prepare for the next earthquake and/or tsunami. Approximately 5000 students, from
both middle schools (ISCED 2) and high schools (ISCED 3), were involved in active learning activities
based on a flipped-up approach during specific online scientific events during the pandemic. Online
lab activities were conducted during European Researchers’ Night (“Earthquakes: history teaches us
the future: researchers for a day with experimentation in didactics for ESL”) and during both World Water
Day 2021 and World Earth Day 2021 (“Tsunamis: history teaches us the future researchers for a day
with experimentation in didactics for ESL”). These two Episodes of Situated Learning (ESL) experiences
triggered students’ interest, favoring remote learning, developing life skills, and focusing on historical
seismic studies of both past earthquakes and tsunamis.This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BYPublished65OS: Terza missioneJCR Journa
Physics-informed loss functions for vertical total electron content forecast
No full textWe design physics-informed loss functions for training Artificial Neural Network (ANN) models to forecast the ionospheric vertical Total Electron Content (vTEC) from 1 to 24 hours in advance. The ANN models exploit our physics-informed loss functions, data provided by the Global Navigation Satellite Systems (GNSS) receiver installed at Tsukuba (36.06 o N, 140.05 o E), Japan, and external drivers (solar and geomagnetic indices). The time series used span from January 1, 2006, to December 31, 2018, i.e., a full solar cycle. A proper set of external drivers for the ANN models training are selected by ranking their importance in relation to the vTEC dynamics at different forecasting horizons. They result to be the 10.7 cm Solar Flux (F10.7), the magnitude of the Interplanetary Magnetic Field (IMF) B T , and the Auroral Electrojet (AE) index. Moreover, a second set of indices among those available has been considered as constraints in the design of the physics-informed loss functions. They are the Disturbance Storm Time (Dst) index, the solar wind speed v, B T , and the By and Bz components of the interplanetary magnetic field. To assess the performance of the resulting ANN models, we use the statistical parameter coefficient of determination (R 2), the standard deviation (SD), and the Wilcoxon non-parametric signed ranked test. We show that, in the testing period analyzed (from 2017-09-13, at 04:40:00, to 2018-12-31, at 23:55:00), one of our physics-informed loss functions provides a better performance of the ANN with regard to the standard loss function commonly adopted. In particular, when the new loss function is used in the ANN model, the average SD is minimized across all forecasting horizons in the training, validation and test datasets. SD is 0.2560 TECU, 0.3183 TECU and 0.4240 TECU for the training, validation and test dataset respectively, where 1 TECU = 10 16 electrons/m 2. The ANN model, incorporating the new loss function and applied to the test dataset, shows a significant improvement according to the Wilcoxon signed ranked test. In fact by selecting a significance level α = 0.05, the probability to obtain results by chance with the new loss function as compared to the standard loss function is 0.01504 (i.e., < α), which implies that the new loss function gives a statistical improvement to the forecasting capability of the ANN model. To the best of our knowledge, this is the first time a physics-informed loss function has been designed for the task of forecasting the ionospheric vTEC.PublishedJCR Journa