CNR Research Institute for Geo-hydrological Protection
CNR Research Institute for Geo-hydrological Protection
Alvioli M.,CNR Research Institute for Geo-hydrological Protection |
Ciofi Degli Atti C.,University of Perugia |
Morita H.,Sapporo Gakuin University
Physical Review C - Nuclear Physics | Year: 2016
Background: The two-nucleon momentum distributions of nucleons N1 and N2 in a nucleus A, nAN1N2(krel,Kc.m.), is a relevant quantity that determines the probability of finding two nucleons with relative momentum krel and center-of-mass (c.m.) momentum Kc.m.; at high values of the relative momentum and, at the same time, low values of the c.m. momentum, nAN1N2(krel,Kc.m.) provides information on the short-range structure of nuclei. Purpose: Our purpose is to calculate the momentum distributions of proton-neutron and proton-proton pairs in He3, He4, C12, O16, and Ca40, in correspondence to various values of krel and Kc.m.. Methods: The momentum distributions for A>4 nuclei are calculated as a function of the relative, krel, and center-of-mass, Kc.m., momenta and relative angle Θ, within a linked cluster many-body expansion approach, based upon realistic local two-nucleon interaction of the Argonne family and variational wave functions featuring central, tensor, and spin-isospin correlations. Results: Independently of the mass number A, at values of the relative momentum krel1.5-2 fm-1 the momentum distributions exhibit the property of factorization, nAN1N2(krel,Kc.m.)≃nrelN1N2(krel)nc.m.N1N2(Kc.m.); in particular, for pn back-to-back pairs one has nApn(krel,Kc.m.=0)≃CApnnD(krel)nc.m.pn(Kc.m.=0), where nD is the deuteron momentum distribution, nc.m.pn(Kc.m.=0) the c.m. motion momentum distribution of the pair, and CApn the pn nuclear contact measuring the number of back-to-back pn pairs with deuteron-like momenta (kp≃-kn,Kc.m.=0). Conclusions: The values of the pn nuclear contact are extracted from the general properties of the two-nucleon momentum distributions corresponding to Kc.m.=0. The Kc.m.-integrated pn momentum distributions exhibit the property nApn(krel)≃CApnnD(krel) but only at very high values of krel, 3.5-4 fm-1. The theoretical ratio of the pp/pn momentum distributions of He4 and C12 and the calculated c.m. motion momentum distributions are in agreement with recent experimental data. © 2016 American Physical Society.
Mondini A.C.,CNR Research Institute for Geo-hydrological Protection
Remote Sensing | Year: 2017
Landslides cause damages and affect victims worldwide, but landslide information is lacking. Even large events may not leave records when they happen in remote areas or simply do not impact with vulnerable elements. This paper proposes a procedure to measure spatial autocorrelation changes induced by event landslides in a multi-temporal series of synthetic aperture radar (SAR) intensity Sentinel-1 images. The procedure first measures pixel-based changes between consecutive couples of SAR intensity images using the Log-Ratio index, then it follows the temporal evolution of the spatial autocorrelation inside the Log-Ratio layers using the Moran's I index and the semivariance. When an event occurs, the Moran's I index and the semivariance increase compared to the values measured before and after the event. The spatial autocorrelation growth is due to the local homogenization of the soil response caused by the event landslide. The emerging clusters of autocorrelated pixels generated by the event are localized by a process of optimal segmentation of the log-ratio layers. The procedure was used to intercept an event that occurred in August 2015 in Myanmar, Tozang area, when strong rainfall precipitations triggered a number of landslides. A prognostic use of the method promises to increase the availability of information about the number of events at the regional scale, and to facilitate the production of inventory maps, yielding useful results to study the phenomenon for model tuning, landslide forecast model validation, and the relationship between triggering factors and number of occurred events. © 2017 by the authors.
Torri D.,CNR Research Institute for Geo-hydrological Protection
Earth-Science Reviews | Year: 2014
Gully head development represents a significant geomorphic process in a wide range of environments. Several studies investigated the critical topographic conditions, expressed by local slope gradient (s) and drainage area (A), controlling the development and position of gully heads in various landscapes. This review examines over 39 publications. After critically analysing the reported threshold data and after standardisation of the procedure to determine the critical topographic conditions for gully head development, i.e., sAb>k or s>kA-b some data sets were discarded because they were not compatible with the standard presentation of data as reported by the majority of studies. Hence, a detailed analysis was made of 63 reported s-A relationships for overland-flow induced gully-heads extracted from data sets collected in various parts of the world. A first examination of the behaviour of both the exponent b and the threshold coefficient k, which reflects the resistance of the site to gully head development, shows clear effects of land use on the value of k whereas the value of b does not seem to be affected. Further analyses are conducted of the recalculated threshold coefficients k, for two predefined constant values of the exponent b. The lowest k-values were observed for cropland followed by values for rangeland, pasture and forest. Effects of climate, rock fragment cover at the soil surface and water storage capacity of the gully catchment on k-values were also shown. The most interesting result is that for a given and constant b-value, the threshold coefficient k can be predicted using soil and vegetation characteristics, based on the NRCS Runoff Curve Number values and on surface rock fragment cover.Furthermore, the underlying physical processes explaining the value of the exponent b were analysed. Finally, a physically-based model, well anchored in the established theories, is proposed as a first step to predict gully head development in various landscapes and under changing environmental conditions. The results of this review clearly show that better and more reliable models can be built, including effects of land use, climate changes and natural disasters. © 2013 Elsevier B.V.
Coscarelli R.,CNR Research Institute for Geo-hydrological Protection |
Caloiero T.,CNR Institute for Agricultural and Forest Systems In the Mediterranean
Journal of Hydrology | Year: 2012
High percentages of the yearly total precipitation concentration in a few very rainy days can increase the risks of floods and soil instability. In this paper, an investigation of the spatial and temporal patterns of daily and monthly precipitation concentration in Calabria (Southern Italy) has been carried out by means of a homogenous daily precipitation data set. The results show that a very dishomogeneous temporal distribution of the daily rainfall characterizes the eastern side of the region with rain gauges in which one quarter of the rainiest days represents almost three quarters of the total pluviometric amount, and a western side which presents a more homogenous temporal distribution of the rainfall. Moreover, the application of the Mann-Kendall test has shown a clear tendency toward a weaker seasonality of the rainfall distribution. © 2011 Elsevier B.V.
Alvioli M.,European Center for Theoretical Studies in Nuclear Physics and Related Areas |
Alvioli M.,CNR Research Institute for Geo-hydrological Protection |
Strikman M.,Pennsylvania State University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013
Color fluctuations in hadron-hadron collisions are responsible for the presence of inelastic diffraction and lead to distinctive differences between the Gribov picture of high energy scattering and the low energy Glauber picture. We find that color fluctuations give a larger contribution to the fluctuations of the number of wounded nucleons than the fluctuations of the number of nucleons at a given impact parameter. The two contributions for the impact parameter averaged fluctuations are comparable. As a result, standard procedures for selecting peripheral (central) collisions lead to selection of configurations in the projectile which interact with smaller (larger) than average strength. We suggest that studies of pA collisions with a hard trigger may allow to observe effects of color fluctuations. © 2013 Elsevier B.V.
Parise M.,CNR Research Institute for Geo-hydrological Protection
Acta Carsologica | Year: 2011
The Murge (Apulia, southern Italy) is the main karst area in the central part of the region, extending from the inland plateau to the Adriatic coastline. Along this transect, a relief energy of a few hundred meters is reached. Even though such relief may seem small when compared to mountain karst areas, actually it is not for Apulia, a very flat carbonate region that acted as the foreland during the building up of the Apenninic Chain in Miocene time. Murge can be subdivided into two sectors: High Murge, the inland plateau, where remnants of an ancient tropical karst are still recognizable; and Low Murge, closer to the sea, with smoother karst morphologies and landforms. Here, some of the most remarkable underground karst systems of Apulia are located: the Castellana caves, a show cave that has been opened since 1939 to tourists (only a few months after the discovery), and the Pozzo Cucù karst system. Overall, the two systems (that are located few hundreds of meters apart) are more than 5,5 km long. In addition, many other karst caves are widespread in the territory, showing different typologies, from percolation shafts, to intrastratal caves, to tectonically-controlled caves, down to marine caves along the coastline. At the surface, other interesting morphological features related to karst may be observed, the main one being the Canale di Pirro polje, which cuts the SE Murge with an E-w strike, until its easternmost reach against the Murge fault line scarp. This latter is the main morphological feature intervening between the Murge plateau and the Adriatic plain. In this article the karst morphological features of Murge are depicted, putting together surface and underground data, in the effort to contribute to the recognition of the main phases of development of karst processes in the region.
Maccherini S.,University of Siena |
Santi E.,CNR Research Institute for Geo-hydrological Protection
Biological Conservation | Year: 2012
Calcareous grasslands are among the most diverse habitats, supporting species-rich vegetation. Propagule limitation and availability of microsites for germination represent major constraints to the successful restoration of these grasslands. To date, little information is available on the effectiveness of seed addition and soil disturbance on the restoration success of encroached semi-natural calcareous grasslands. Here, we conducted a 1year before - 9year after control-impact (BACI) study aimed at testing the effect of the addition of seeds of native species and livestock grazing on calcareous grasslands. Each restoration measure and their combination differed in their impact on these communities and varied over time. Grazing had a significant, beneficial, impact on these communities, although the impact was species-specific. On average, grazed plots were characterized by a higher number of species and a lower vegetation cover. Nine years after treatment application, grazed site were dominated by Trifolium incarnatum subsp. molinerii, Xeranthemum cylindraceum, Orlaya grandiflora, Teucrium chamaedrys and Bromus erectus while ungrazed sites were dominated by B. erectus, X. cylindraceum, O. grandiflora and Prunus spinosa. Only 8 out of 34 species responded significantly to disturbance or/and disturbance and seed addition while 22 species were significantly affected by the sampling year and 18 by a blocking factor. The low recruitment from added seeds and the fact that seed addition is a time-and labor-consuming activity suggests that an adequate level of disturbance and natural regeneration represent the most cost-effective approach to the restoration of these calcareous grasslands. © 2011 Elsevier Ltd.
Wasowski J.,CNR Research Institute for Geo-hydrological Protection |
Bovenga F.,CNR Institute of Intelligent Systems for Automation
Engineering Geology | Year: 2014
Multi Temporal Interferometry (MTI) stands for advanced synthetic aperture radar differential interferometry (DInSAR) techniques, which include Permanent/Persistent Scatterers Interferometry - PSInSAR™/PSI and similar methods, as well as Small Baseline Subset - SBAS and related/hybrid approaches. These techniques are capable to provide wide-area coverage (thousands of km2) and precise (mm-cm resolution), spatially dense information (from hundreds to thousands of measurement points/km2) on ground surface deformations. New MTI application opportunities are emerging thanks to i) greater data availability from radar satellites, and ii) improved capabilities of the new space radar sensors (X-band Cosmo-SkyMed, C-band RADARSAT-2, TerraSAR-X) in terms of resolution (from 3 to 1m) and revisit time (from 11 to 4days for X-band acquisitions). This implies greater quantity and quality information about ground surface displacements and hence improved landslide detection and monitoring capabilities. Even though the applicability of MTI to regional and local-scale investigations of slow landslides has already been demonstrated, the awareness of the MTI utility and its technical limitations among landslide scientists and practitioners is still rather low. By referring to recent works on radar remote sensing, many regional and local scale MTI application examples from the geoscience literature and our own studies, we present an up-to-date overview of current opportunities and challenges in this field. We discuss relevant technical constraints and data interpretation issues that hamper the use of MTI in landslide assessment. Then guidelines on how to mitigate MTI technical limitations and avoid erroneous interpretations of radar-derived slope surface deformations are presented for the benefit of users lacking advanced knowledge in SAR applications. Finally, in view of the upcoming radar satellite launches, future perspectives on MTI applications are outlined and recommendations for applied research priorities are suggested. We foresee that with regular globe-scale coverage, improved temporal resolution (weekly or better) and freely available imagery, new radar satellite background missions such as the European Space Agency's Sentinel-1 will guarantee ever increasing and more efficient use of MTI in landslide investigations. Furthermore, thanks to the improved temporal and spatial resolutions of the new generation radar sensors, significant breakthroughs are expected in detailed slope instability process modeling (e.g. kinematic and geotechnical models), as well as in the understanding of spatial and temporal patterns of landslide movement/activity and their relationships to causative or triggering factors (e.g. precipitation, seismic loading). © 2014 Elsevier B.V.
Parise M.,CNR Research Institute for Geo-hydrological Protection |
Lollino P.,CNR Research Institute for Geo-hydrological Protection
Geomorphology | Year: 2011
Natural and anthropogenic caves may represent a potential hazard for the built environment, due to the occurrence of instability within caves, that may propagate upward and eventually reach the ground surface, inducing the occurrence of sinkholes. In particular, when caves are at shallow depth, the effects at the ground surface may be extremely severe. Apulia region (southern Italy) hosts many sites where hazard associated with sinkholes is very serious due to presence of both natural karst caves and anthropogenic cavities, the latter being mostly represented by underground quarries. The Pliocene-Pleistocene calcarenite (a typical soft rock) was extensively quarried underground, by digging long and complex networks of tunnels. With time, these underground activities have progressively been abandoned and their memory lost, so that many Apulian towns are nowadays located just above the caves, due to urban expansion in the last decades. Therefore, a remarkable risk exists for society, which should not be left uninvestigated.The present contribution deals with the analysis of the most representative failure mechanisms observed in the field for such underground instability processes and the factors that seem to influence the processes, as for example those causing weathering of the rock and the consequent degradation of its physical and mechanical properties. Aimed at exploring the progression of instability of the cavities, numerical analyses have been developed by using both the finite element method for geological settings represented by continuous soft rock mass, and the distinct element method for jointed rock mass conditions. Both the effects of local instability processes occurring underground and the effects of the progressive enlargement of the caves on the overall stability of the rock mass have been investigated, along with the consequent failure mechanisms. In particular, degradation processes of the rock mass, as a consequence of wetting and weathering phenomena in the areas surrounding the caves, have been simulated. The results obtained from the numerical simulations have then been compared with what has been observed during field surveys and a satisfactory agreement between the numerical simulations and the instability processes, as detected in situ, has been noticed. © 2011 Elsevier B.V.
Petrucci O.,CNR Research Institute for Geo-hydrological Protection
Natural Hazards and Earth System Science | Year: 2013
The paper presents a methodology for relative damage assessment for historical landslide events, i.e. periods during which damage caused by rainfall-triggered landslides affected wide areas. The approach requires a minimum amount of data, and it is based on the assessment of direct, indirect and intangible damage indices at municipal and regional scale. An application to major events which occurred in Calabria (Italy) highlighted roads as the most vulnerable element, even representing the source of intangible damage for people forced to use alternative roads for their daily activities. Indirect costs seem mainly tied to displacement of people even for short periods. © 2013 Author(s).