Integration of geochemical and geophysical data at a NAPL-contaminated site

The joint use of borehole geo-electrical measurements and the chemico-physical monitoring of the subsoi is discussed; it permitted in the specific case to locate the zone characterized by intense bio-degradation activity, demonstrating the effectiveness of the integrated approac

Georadar measurements for the snow cover density

Ground Probing Radar (GPR) devices is adopted for the analysis of thickness and the mechanical properties (density) of the snow cover in some test site in Alps, in Northern Italy. The performances of standard radar systems for the snow cover characterisation are analysed, the main aim is to assess the reliability of the method to estimate the snow density, the snowpack thickness and the depth resolution in terms of capability to detect thin layers. The main relationships between the electrical permittivity and the density of the dry-snow are applied to estimate the density vertical profiles inferred by the GPR investigation. The data were calibrated and compared with the results coming from direct measurements of the density and thickness. © 2009 Science Publications

An overview on cryogeophysics in the alpine environment

Geophysics allows us to characterise glaciers and snow properties in order to evaluate the hazard associated with the evolution of the snow/ice masses. The danger is often associated with recent phenomena of rapid deglaciation with consequent collapses of ice and rock, or with releases of water contained in the glaciers. The morphology of the rock substrate and the presence of various kinds of conduits and cavities, making up the internal hydrological network, can be investigated by seismic and radar methods; the presence of water in internal cavities of temperate glaciers can be successfully detected through georadar measurements. In the nivological context, the geophysical approach, adopting seismic and electromagnetic methods, can serve as a tool to characterise and monitor some physical properties of the snowpack. The evaluation of these parameters makes it possible to estimate the risk and the imminence associated with the snow-gliding avalanche release. We discuss the basic theoretical background of the relationships between geophysical investigated parameters and ice/snow properties; moreover, we illustrate some examples of applications of seismic and electromagnetic methods to detect the snow and ice properties in high elevation Alpine regions

Laboratory testing of FBGs for pipeline monitoring

The monitoring of the effects of geohazards on pipelines can be addressed by optical fiber Bragg gratings (FBGs). They are sensitive to strain and bending, and are installed on the external surface of pipelines at discrete locations. A joint approach of theoretical analysis and laboratory experiments is useful to check the reliability of the performance of this technology. We focus on the theoretical analysis of pipeline buckling and investigate the reliability of FBG monitoring both by examining the analytical model available and by performing a laboratory-scale experiment. The novelty lies in the analysis of models and methods originally developed for the detection of pipeline upheaval buckling caused by externally imposed forces in the context of service loads (temperature). Although thermal strain is very relevant in view of its potentially disruptive effects on both pipelines and the FBG response, it has not been yet fully investigated. We point out the merits of the approach, such as the functionality and simplicity of design, the accessibility and inexpensiveness of materials, the controllability and repeatability of processes, the drawbacks are also described, such as temperature effects, the problem of slipping of gages and the challenge of performing quasi-distributed strain measurements

P-wave and surface wave survey for permafrost analysis in alpine regions

We discuss the results of seismic survey to delineate temporal and spatial changes of frozen layer in Alpine environments. The seismic characterization allows us to detect changes of soil deformability properties related to the temperature effect on subsoi

Analysis of borehole guided waves for geotechnical application

The reliability of Stoneley waves (SWs) is discussed for the characterisation of the mechanical properties of soft and hard rock in borehole seismic techniques using source on the surface and hydrophones as receivers. The SWs propagate along the fluid-filled borehole; the propagation is affected by the mechanical and hydraulic properties of the fluid and the surrounding medium. At low frequencies, in a non-diffusive medium (impermeable formation), the wave velocity depends on the density, the wave velocity of the fluid and the shear modulus of the formation. The models adopted to infer the wave velocity in elastic formations in uncased and cased boreholes are discussed. We discuss two examples to check the discrepancies between the theoretical and the experimental evidence. The presence of casing in soft rock greatly reduces the sensitivity of the SW propagation to the mechanical properties of the medium. In hard rock, the scattering of the primary wavefields could be adopted to detect the presence of rock mass discontinuities (fractures). © 2007 - OGS

Seir modeling of the italian epidemic of sars-cov-2 using computational swarm intelligence

We applied a generalized SEIR epidemiological model to the recent SARS-CoV-2 outbreak in the world, with a focus on Italy and its Lombardy, Piedmont, and Veneto regions. We focused on the application of a stochastic approach in fitting the model parameters using a Particle Swarm Optimization (PSO) solver, to improve the reliability of predictions in the medium term (30 days). We analyzed the official data and the predicted evolution of the epidemic in the Italian regions, and we compared the results with the data and predictions of Spain and South Korea. We linked the model equations to the changes in people’s mobility, with reference to Google’s COVID-19 Community Mobility Reports. We discussed the effectiveness of policies taken by different regions and countries and how they have an impact on past and future infection scenarios

Special Issue “Remote Sensing in Applied Geophysics”

The Special Issue "Remote Sensing in Applied Geophysics" is focused on recent and upcoming advances in the combined application of remote sensing and applied geophysics techniques, sharing the advantages of being non-invasive research methods, suitable for surface and near-surface high-resolution investigations of even wide and remote areas. Applied geophysics analyzes the distribution of physical properties in the subsurface for a wide range of geological, engineering and environmental applications at different scales. Geophysical surveys are usually carried out deploying or moving the appropriate instrumentation directly on the ground surface. However, recent technological advances have brought to the development of innovative acquisition systems more typical of the remote sensing community (e.g., airborne surveys and unmanned aerial vehicle systems). At the same time, while applied geophysics mainly focuses on the subsurface, typical remote sensing techniques have the ability to accurately image the Earth's surface with high-resolution investigations carried out by means of terrestrial, airborne, or satellite-based platforms. The integration of surface and subsurface information is often crucial for several purposes, including the georeferencing and processing of geophysical data, the characterization and time-lapse monitoring of surface and near-surface targets, and the reconstruction of highly detailed and comprehensive 3D models of the investigated areas. Contributions to the issue showing the added value of surface reconstruction and/or monitoring in the processing and interpretation of geophysical data, integration and cross-comparison of geophysical and remote sensing techniques were required to the research community. Contributions discussing the results of pioneering geophysical acquisitions by means of innovative remote systems were also addressed as interesting topics. The Special Issue received great attention in the combined community of applied geophysicists and remote sensing researchers. A total of 15 papers are included in the Special Issue, covering a wide range of applications. This is one of the highest number of papers among the Remote Sensing Special Issues, showing great interest in the proposed topic. The relevant number of contributions also highlights the relevance and increasing need for integration between remote sensing and ground-based geophysical exploration or monitoring methods. In particular, one of the main fields of research showing the potential integration of the geophysical and remote sensing techniques is archaeological exploration

Ambient seismic noise and microseismicity monitoring of a prone-to-fall quartzite tower (Ormea, NW Italy)

Remote sensing techniques are leading methodologies for landslide characterization and monitoring. However, they may be limited in highly vegetated areas and do not allow for continuously tracking the evolution to failure in an early warning perspective. Alternative or complementary methods should be designed for potentially unstable sites in these environments. The results of a six-month passive seismic monitoring experiment on a prone-to-fall quartzite tower are here pre-sented. Ambient seismic noise and microseismicity analyses were carried out on the continuously recorded seismic traces to characterize site stability and monitor its possible irreversible and reversible modifications driven by meteorological factors, in comparison with displacement measured on site. No irreversible modifications in the measured seismic parameters (i.e., natural resonance fre-quencies of the tower, seismic velocity changes, rupture-related microseismic signals) were detected in the monitored period, and no permanent displacement was observed at the tower top. Results highlighted, however, a strong temperature control on these parameters and unusual preferential vibration directions with respect to the literature case studies on nearly 2D rock columns, likely due the tower geometric constraints, as confirmed by 3D numerical modeling. A clear correlation with the tower displacement rate was found in the results, supporting the suitability of passive seismic monitoring systems for site characterization and early waning purposes

La liberación inmediata de buques en procedimientos de medidas provisionales. ¿Nuevas tendencias y desafíos?

This article discusses the incidents and situations created when vessels are detained in foreign ports, and the measures that need to be undertaken to overcome these disputes, analyzing the United Nations Convention on the Law of the Sea; that not only provides a frame that all States (who have submitted) should constrain to, but also contributes to define the peaceful means for settlements intended to overcome such controversial situations. Apart from the consideration of all these regulations, jurisprudence and real precedents are explored. In first place, to perceive the way parties react towards these situations, and also to understand how the settlement of disputes be operationalized through the International Tribunal for the Law of the Sea. For this purpose, contemporary cases such as the Grand Prince, the ARA Libertad, and the Artic Sunrise are deepened.En el presente artículo se ven plasmados los incidentes que pueden presentarse cuando los buques y sus tripulaciones son detenidos en puertos extranjeros, y las distintas medidas a tomar ante estas controversias, analizando la Convención de las Naciones Unidas sobre el Derecho del Mar, que no solo provee una regulación marco a la que todos los Estados signatarios deben adecuarse, sino que también contribuye con la enunciación de las distintas formas de solución pacífica creadas para superar estas situaciones. Además de considerar estas regulaciones, es necesario analizar la jurisprudencia al respecto. En primer lugar, ya que ayuda a visualizar la forma en que los Estados actúan frente a estas situaciones y asimismo para comprender cómo el sistema de solución de controversias ha sido llevado a la práctica por el Tribunal de Hamburgo. Con esa finalidad profundizamos sobre algunos casos contemporáneos como el Grand Prince, el ARA Libertad y el Artic Sunrise