Groundwater of Rome

This paper describes the contents of the new Hydrogeological Map of the City of Rome (1:50,000 scale). The map extends to the entire municipality (1285 km2) and is based on both the most recent scientific studies on the groundwater field and new survey activities carried out in order to fill the data gaps in several areas of the examined territory. The map is the result of a combination of different urban groundwater expertise and Geographic Information System (GIS)-based mapping performed using the most recent available data and has been produced with the intention of furnishing the City of Rome with the most recent and updated information regarding groundwater

Early stage sinkhole formation in the acque albule basin of central Italy from geophysical and geochemical observations

Sinkhole occurrence along the Tyrrhenian margin of the Central Apennines is of great importance for applied research, land management and civil protection. This study reports on GPS-altimetry magnetic, gravity, geoelectric, seismic, and soil gas measurements of a rapidly developing sinkhole near the Guidonia military airport. The measurements revealed an elliptical 2-m depression elongated 220 m in the NNE-SSW direction with the minor axis of 110 m. In spring of 2013, two vertical cavities formed in the eastern and northeastern flanks of the depression whose depths and shapes are rapidly evolving with the formation of widespread fracturing along the same side. The geophysical observations image the developing sinkhole to a depth of some 50 m, the presence of the Travertino lithotype around the depression (down to at least 40 m), and the lack of this lithotype below the lowered area. The sinkhole's evolution appears to be structurally controlled by local and regional faulting. These results are useful for designing further geophysical, geotechnical and geochemical studies to monitor the sinkhole's evolution and to assess the hazard it presents in densely urbanized area.Published36-477A. Geofisica di esplorazioneJCR Journalreserve

Geochemistry of soil gas in the seismic fault zone produced by the Wenchuan Ms 8.0 earthquake, southwestern China

The spatio-temporal variations of soil gas in the seismic fault zone produced by the 12 May 2008 Wenchuan Ms 8.0 earthquake were investigated based on the field measurements of soil gas concentrations after the main shock. Concentrations of He, H2, CO2, CH4, O2, N2, Rn, and Hg in soil gas were measured in the field at eight short profiles across the seismic rupture zone in June and December 2008 and July 2009. Soil-gas concentrations of more than 800 sampling sites were obtained. The data showed that the magnitudes of the He and H2 anomalies of three surveys declined significantly with decreasing strength of the aftershocks with time. The maximum concentrations of He and H2 (40 and 279.4 ppm, respectively) were found in three replicates at the south part of the rupture zone close to the epicenter. The spatio-temporal variations of CO2, Rn, and Hg concentrations differed obviously between the north and south parts of the fault zone. The maximum He and H2 concentrations in Jun 2008 occurred near the parts of the rupture zone where vertical displacements were larger. The anomalies of He, H2, CO2, Rn, and Hg concentrations could be related to the variation in the regional stress field and the aftershock activity

The consolidated European synthesis of CH₄ and N₂O emissions for the European Union and United Kingdom: 1990–2019

Knowledge of the spatial distribution of the fluxes of greenhouse gases (GHGs) and their temporal variability as well as flux attribution to natural and anthropogenic processes is essential to monitoring the progress in mitigating anthropogenic emissions under the Paris Agreement and to inform its global stocktake. This study provides a consolidated synthesis of CH₄ and N₂O emissions using bottom-up (BU) and top-down (TD) approaches for the European Union and UK (EU27 + UK) and updates earlier syntheses (Petrescu et al., 2020, 2021). The work integrates updated emission inventory data, process-based model results, data-driven sector model results and inverse modeling estimates, and it extends the previous period of 1990–2017 to 2019. BU and TD products are compared with European national greenhouse gas inventories (NGHGIs) reported by parties under the United Nations Framework Convention on Climate Change (UNFCCC) in 2021. Uncertainties in NGHGIs, as reported to the UNFCCC by the EU and its member states, are also included in the synthesis. Variations in estimates produced with other methods, such as atmospheric inversion models (TD) or spatially disaggregated inventory datasets (BU), arise from diverse sources including within-model uncertainty related to parameterization as well as structural differences between models. By comparing NGHGIs with other approaches, the activities included are a key source of bias between estimates, e.g., anthropogenic and natural fluxes, which in atmospheric inversions are sensitive to the prior geospatial distribution of emissions. For CH₄ emissions, over the updated 2015–2019 period, which covers a sufficiently robust number of overlapping estimates, and most importantly the NGHGIs, the anthropogenic BU approaches are directly comparable, accounting for mean emissions of 20.5 Tg CH₄ yrc (EDGARv6.0, last year 2018) and 18.4 Tg CH₄ yr⁻¹ (GAINS, last year 2015), close to the NGHGI estimates of 17.5±2.1 Tg CH₄ yr⁻¹. TD inversion estimates give higher emission estimates, as they also detect natural emissions. Over the same period, high-resolution regional TD inversions report a mean emission of 34 Tg CH₄ yr⁻¹. Coarser-resolution global-scale TD inversions result in emission estimates of 23 and 24 Tg CH₄ yr⁻¹ inferred from GOSAT and surface (SURF) network atmospheric measurements, respectively. The magnitude of natural peatland and mineral soil emissions from the JSBACH–HIMMELI model, natural rivers, lake and reservoir emissions, geological sources, and biomass burning together could account for the gap between NGHGI and inversions and account for 8 Tg CH₄ yr⁻¹. For N₂O emissions, over the 2015–2019 period, both BU products (EDGARv6.0 and GAINS) report a mean value of anthropogenic emissions of 0.9 Tg N₂O yr⁻¹, close to the NGHGI data (0.8±55 % Tg N₂O yr⁻¹). Over the same period, the mean of TD global and regional inversions was 1.4 Tg N₂O yr⁻¹ (excluding TOMCAT, which reported no data). The TD and BU comparison method defined in this study can be operationalized for future annual updates for the calculation of CH₄ and N₂O budgets at the national and EU27 + UK scales. Future comparability will be enhanced with further steps involving analysis at finer temporal resolutions and estimation of emissions over intra-annual timescales, which is of great importance for CH₄ and N₂O, and may help identify sector contributions to divergence between prior and posterior estimates at the annual and/or inter-annual scale. Even if currently comparison between CH₄ and N₂O inversion estimates and NGHGIs is highly uncertain because of the large spread in the inversion results, TD inversions inferred from atmospheric observations represent the most independent data against which inventory totals can be compared. With anticipated improvements in atmospheric modeling and observations, as well as modeling of natural fluxes, TD inversions may arguably emerge as the most powerful tool for verifying emission inventories for CH₄, N₂O and other GHGs. The referenced datasets related to figures are visualized at https://doi.org/10.5281/zenodo.7553800 (Petrescu et al., 2023)

Condividere un segreto sul Web

In svariate applicazioni, ha senso affidare un'informazione segreta, qui semplicemente denominata “il segreto”, a un gruppo di soggetti che, nel rispetto di precise regole pre-stabilite, possono decidere di utilizzare tale informazione segreta per perseguire i loro scopi istituzionali. Si pensi, ad esempio, ad un consiglio di amministrazione il cui presidente, che custodisce in una cassetta di sicurezza documenti importanti e riservati, desideri affidare ai membri del consiglio il codice di accesso alla cassetta, stabilendo che ciò possa essere effettivamente compiuto solo nel caso in cui almeno la metà più uno dei componenti del consiglio concordi nell'accedere alle informazioni riservate. Più in generale, condividere un segreto che consente l’accesso ad una risorsa comune può rappresentare un problema nel caso in cui debbano essere mantenuti elevati i livelli di affidabilità e confidenzialità del segreto stesso, che può consistere in una chiave, passphrase, PIN, combinazione o altro. Infatti, affidare il segreto ad un solo soggetto per garantirne la riservatezza non assicura un’adeguata affidabilità nel caso in cui questo venisse accidentalmente smarrito, distrutto, alterato ecc.; per non parlare poi dei possibili usi fraudolenti del segreto da parte dell'unico affidatario. D’altra parte, affidare l'intero segreto a più soggetti aumenta la probabilità che uno di essi lo utilizzi impropriamente. Un approccio che offre una terza possibilità, intermedia rispetto i due casi estremi menzionati, è stato presentato da Shamir nel 1979 ed è basato sulla suddivisione del segreto in parti, in modo tale che comunque siano scelte di esse, queste siano sufficienti per ricostruirlo, ma la conoscenza di parti non riveli alcuna informazione riguardo il segreto . Tale approccio è stato denominato “condivisione di un segreto alla Shamir” ed è assai noto nella letteratura specializzata. Nonostante la sua notorietà ed eleganza matematica, basata sulle proprietà dell'interpolazione polinomiale, alcune caratteristiche intrinseche ne limitano l'usabilità: l'approccio non consente di determinare se e quando il segreto è stato ricostruito e neanche da chi. L'approccio è stato altresì sfruttato in alcuni domini applicativi specifici, in cui tali limitazioni non appaiono rilevanti. In questo lavoro presentiamo una applicazione Web basata sullo schema di Shamir, sviluppata alla Sapienza di Roma, che consente la condivisione di segreti sul Web in maniera sicura. L'applicazione permette di definire le identità degli soggetti con cui condividere il segreto e di scegliere la soglia , per la ricostruzione. In tal senso, l'applicazione realizza il sistema di condivisione di un segreto alla Shamir fra utenti remoti che sono collegati a Internet, scegliendo anche la soglia . Essa fa uso di un sistema centrale di riferimento, Web-accessibile, al quale si connettono numerosi altri client sparsi sull'intera rete e che consente ai partecipanti di collaborare senza la necessità di interazioni dirette. Rispetto allo schema originale di Shamir, l'applicazione offre funzionalità aggiuntive che permettono di superare i tradizionali limiti. In particolare, l'applicazione supporta gli utenti nella ricostruzione del segreto, impedendo ricostruzioni autonome: ciò permette di stabilire quando e da chi il segreto è stato ricostruito. Tutte le comunicazioni tra le diverse componenti (client, server) dell’applicazione sono state protette con un doppio livello di sicurezza crittografica che fornisce costantemente affidabilità, confidenzialità ed autenticità delle informazioni trasmesse. Per valutare la sicurezza del sistema di condivisione di segreti realizzato è stata utilizzata un’architettura di calcolo basata su GPU per considerare le reali potenzialità di un attaccante. Le analisi condotte hanno mostrato che un attaccante in grado di entrare in possesso dell’intera base di dati non ha la possibilità di ottenere in alcun caso informazioni sensibili riguardanti il segreto o le chiavi generate, in quanto sono state adottate opportune tecniche per la protezione dei dati che il sistema centrale mantiene per la gestione dei segreti amministrati. In conclusione, il sistema da noi realizzato offre le funzionalità pensate originariamente da Shamir, con alcune migliorie, che consentono di sapere chi ha ricostruito il segreto e quando, e impediscono operazioni di sabotaggio durante la fase di ricostruzione del segreto. Il sistema è Web-accessibile e dotato di un doppio livello di cifratura ed è resistente ad attacchi. Permette la fruizione del servizio a un gruppo di utenti che comunicano attraverso Internet, senza aver bisogno di specifiche infrastrutture di sicurezza né di sincronizzazione. Gli utenti, in particolare, non necessitano di pre-condivisione di chiavi, password o altro, né hanno la necessità di incontrarsi. Il sistema usa tecnologie standard e collaudate e può venire utilizzato, oltre che da gruppi di utenti, anche da applicazioni terze, grazie alle REST API da esso offerte. Il codice sorgente del sistema è disponibile alla pagina http://www.dis.uniroma1.it/~damore/sss/

A multidisciplinary, statistical approach to study the relationships between helium leakage and neotectonic activity in a gas province: The Vasto basin Abruzzo-Molise (central Italy)

The evaluation of a new method based on the integration of geochemical, morphological, and structural analyses for the study of neotectonics in clay basins is presented. More than 900 helium so gas samples were collected over an area located in the central sector of the Adriatic foredeep (central Italy). Soil-gas distribution has been compared with the location and orientation of the main structural features described in the literature and/or characterized by field surveys and morphotectonic features obtained by air-photo interpretation and drainage network analysis. Collected data were statistically analyzed and compared by means of rose diagram plots. A geostatistical approach was used to describe the spatial behavior of the helium distribution. The comparison of the morphological and structural elements with the observed geochemical anomalies shows that the northwest-southeast is the most representative direction in agreement with the known Apennine structural trends. Moreover, the presence of north-south and east-west trends in the helium regional distribution, observed in the central and southern sectors of the studied area, is thought to be caused by a more recent deformation phase acting along these directions. This hypothesis is strengthened by the good correspondence, both at regional and local scales between geochernical data and the results of the structural and geomorphological analyses. Furthermore, the magnitude and the anisotropic distribution of the helium anomalies in the residual maps indicate that at local scale, this gas could be related with the distribution of the hydrocarbon reservoirs occurring in the area

Short and Long Term Gas Hazard: The Release of Toxic Gases in the Alban Hills Volcanic Area (Central Italy).

In the Alban Hills area, strong areally diffuse and localised spot degassing processes occur. The gas comprises a large proportion of CO2, with minor CH4, H2S and Rn. These advective features are generated by fluid leakage from buried reservoirs hosted in the structural highs of the Mesozoic carbonate basement. Gas migration towards the surface is controlled by fault and fracture systems bordering the structural highs of the carbonate formations (e.g. Ciampino high). Both the sudden and catastrophic, and slow and continuous gas release at surface, of naturally occurring toxic species (CO2, H2S and Rn) poses a serious health risk to people living in this geologically active area. This paper presents data obtained from soil gas and gas flux surveys, as well as gas isotopes analyses, which suggest the presence of a deep origin gas flux enriched in carbon dioxide and minor species (CH4 and H2S), as well as a channelled migration of geogas mixtures having a Rn component which is not produced in situ. In regards to the health risk to local inhabitants, it was found that some anomalous areas had been zoned as parkland while others had been heavily developed for residential purposes. For example, many new houses were found to have been built on ground which has soil gas CO2 concentrations of over 70% and a CO2 flux of about 0.7 kg m_ 2 day_ 1, as well as radon values of more than 250 kBq/m3. In addition, an indoor radon survey has been conducted in selected houses in the town of Cava dei Selci to search for a possible correlation between the local geology and the radon concentration in indoor air. Preliminary results indicate high indoor values at ground floor levels (up to 1000 Bq/m3) and very high values in the cellars (up to 250.000 Bq/m3). It is recommended that land-use planners incorporate soil gas and/or gas flux measurements in the environmental assessment of areas of possible risk (i.e. volcanic or structurally active areas)