New algorithms for shoreline monitoring from coastal video systems     

Nico Valentini  Alessandra Saponieri  Matteo Gianluca Molfetta  Leonardo Damiani 《Earth Science Informatics》2017,10(4):495-506

Video systems have become widely used all around the world in coastal monitoring strategies, allowing both high temporal and spatial sampling frequency, with low logistic and costs efforts. The present paper deals with a new tool for coastal images processing, aimed at the automatic shoreline detection and data analysis. The tool is composed by a shoreline detection routine implemented in a web-application, addressed at images processing (i.e. shoreline extraction and geo-rectification), data analysis and sharing results about beach actual state and shore evolution in quasi-real time. The Shoreline Detection Model (SDM) is based on a new algorithm, implementing image-processing procedures, which allows extracting the sea/land boundary from automatic segmented Timex images. The SDM calibration and validation has been performed on different coastal images derived from a video monitoring system installed at Alimini (Lecce, IT) in 2005, by comparing automatic shoreline contours with the manual detected ones. Moreover, in December 2015, new video monitoring systems were installed in South Italy (Porto Cesareo and Torre Canne, Apulia region), at sandy beaches affected by erosion phenomena. The application of the SDM on images recorded by the new systems has allowed testing the model feasibility at sites characterized by different morphological features and geographical exposition. The present describes in detail the SDM algorithm and the image processing procedures used. The results of the model calibration and validation performed at Alimini and the tests performed at Porto Cesareo on first images are reported.  相似文献   

Cambro-Silurian magmatisms at the northern Gondwana margin (Penninic basement of the Ligurian Alps)   总被引：1，自引：0，他引：1  

Matteo Maino  Laura Gaggero  Antonio Langone  Silvio Seno  Mark Fanning 《地学前缘(英文版)》2019,10(1):315-330

The Early Paleozoic evolution of the northern margin of Gondwana is characterized by several episodes of bimodal magmatism intruded or outpoured within thick sedimentary basins. These processes are well recorded in the Variscan blocks incorporated in the Ligurian Alps because they experienced low temperature Alpine metamorphism. During the Paleozoic, these blocks, together with the other Alpine basements, were placed between the Corsica-Sardinia and the Bohemian Massif along the northern margin of Gondwana. In this framework, they host several a variegated lithostratigraphy forming two main complexes(Complexs I and II) that can be distinguished by both the protoliths and their crosscutting relationships, which indicate that the acidic and mafic intrusives of Complex II cut an already folded sequence made of sediments, basalts and granitoids of Complex I. Both complexes were involved in the Variscan orogenic phases as highlighted by the pervasive eclogite-amphibolite facies schistosity(foliation II). However, rare relicts of a metamorphic foliation at amphibolite facies conditions(foliation I)is locally preserved only in the rocks of Complex I. It is debatable if this schistosity was produced during the early folding event e occurred between the emplacement of Complex I and II e rather than during an early stage of the Variscan metamorphic cycle.New SHRIMP and LA ICP-MS Ue Pb zircon dating integrated with literature data, provide emplacement ages of the several volcanic or intrusive bodies of both complexes. The igneous activity of Complex I is dated between 507 ± 15 Ma and 494 ± 5 Ma, while Complex II between 467 ± 12 Ma and 445.5 ± 12 Ma.The folding event recorded only by the Complex I should therefore have occurred between 494 ± 5 Ma and 467 ± 12 Ma. The Variscan eclogite-amphibolite facies metamorphism is instead constrained between ~420 Ma and ~300 Ma. These ages and the geochemical signature of these rocks allow constraining the Early Paleozoic tectono-magmatic evolution of the Ligurian blocks, from a middleeupper Cambrian rifting stage, through the formation of an Early Ordovician volcanic arc during the Rheic Ocean subduction, until a Late Ordovician extension related to the arc collapse and subsequent rifting of the PaleoThetys. Furthermore, the ~420-350 Ma ages from zircon rims testify to thermal perturbations that may be associated with the Silurian rifting-related magmatism, followed by the subduction-collisional phases of the Variscan orogeny.  相似文献   

Dissolution of nanocrystalline fluorite powders: An investigation by XRD and solution chemistry     

Giovanni De Giudici  Riccardo Biddau  Matteo Leoni 《Geochimica et cosmochimica acta》2005,69(16):4073-4083

The effect of lattice disorder and mineral surface area on the reactivity of finely ground fluorite was studied on ball-milled powders. Structural information was provided by X-ray whole powder pattern modeling (WPPM). The mean size of coherent scattering domains decreases with milling time from 70 nm to ∼20 nm, whereas the density of lattice defects increases with both time and intensity of milling treatment, from 4 × 10¹⁵ m^-2 to 24 × 10¹⁵ m^-2. High resolution transmission electron microscopy (HRTEM) of ground fluorite grains shows several line defects and a general tendency of nanometric crystalline domains to agglomerate in larger grains.Solution chemistry was investigated using batch reactors with free drift of solution saturation state with respect to fluorite. Total surface area was measured by the Brunaver, Emmet and Teller (BET) method, and dissolution rates were measured at pH = 2 (HCl) and T = 295 K. In far from equilibrium conditions, dissolution rates normalized by BET area do not increase with the dislocation density. In near-equilibrium condition, however, measured stationary ionic product clearly increases with both time and intensity of milling treatment. Thermodynamic predictions of the solubility constant indicate negligible or little effect of total surface area. Consequently, the observed increase in the stationary ionic product can be related to the increasing lattice defect content. This confirms the significant role of dislocation outcrops on mineral dissolution in close to equilibrium conditions.  相似文献   

Root tensile strength relationships and their slope stability implications of three shrub species in the Northern Apennines (Italy)   总被引：12，自引：1，他引：12  

Matteo Tosi   《Geomorphology》2007,87(4):268-283

The role of root strength is important in stabilising steep hillslopes which are seasonally affected by storm-induced shallow landslides. In the Italian Apennines, steep (25–40°) slopes underlain by mudstone are generally stable if they are covered by shrubs whose roots anchor into the soil mantle. To quantify the mechanical reinforcement of roots to soil, the root tensile breaking force and the root tensile strength of three autochthonous shrub species commonly growing on stiff clay soils of the Northern Italian Apennines, Rosa canina (L.), Inula viscosa (L.) and Spartium junceum (L.), were measured by means of field and laboratory tests. For each test approximately 150 root specimens were used. The tensile force increases with increasing root diameter following a second-order polynomial regression curve. The tensile strength decreases with increasing root diameter following a power law curve. The field in situ tensile force required to break a root is always smaller than that obtained from laboratory tests for the same root diameter, although their difference becomes negligible if the root diameter is smaller than 5 mm. The influence of root tensile strength on soil shear strength was verified based on the infinite slope stability model. The root reinforcement was calculated using the number and mean diameter of roots. The factor of safety was calculated for three different soil thickness values (0.1, 0.3, and 0.6 m) and topographic slopes between 10° and 45°. The factor of safety for the combination of 0.6 m soil thickness, slopes smaller than 30°, and vegetation of I. viscosa (L.) or S. junceum (L.) is always larger than 1. If a slope is steeper, the factor of safety may be smaller than 1 for I. viscosa (L.), although it is still larger than 1 for S. junceum (L.). In the stiff clayey areas of the Northern Italian Apennines, I. viscosa (L.) mainly colonizes fan/cone/taluses and stabilises these zones up to a topographic gradient < 30° for a soil 0.6 m thick. S. junceum (L.) colonizes not only fan/cone/taluses but also headwalls and cliffs and, for a 0.6 m thick soil, it stabilises these areas up to 45°. The effectiveness of this reinforcement, however, depends strongly on the frequency of soil and seasonal grass vegetation removal due to shallow landsliding before the entrance of the shrub species.  相似文献   

Using GB-SAR technique to monitor slow moving landslide   总被引：3，自引：0，他引：3  

Linhsia Noferini  Massimiliano Pieraccini  Daniele Mecatti  Giovanni Macaluso  Carlo Atzeni  Matteo Mantovani  Gianluca Marcato  Alessandro Pasuto  Sandro Silvano  Fabrizio Tagliavini 《Engineering Geology》2007,95(3-4):88-98

A Ground-Based SAR (GB-SAR) interferometer was employed to measure the surface displacements of a landslide occurring in the Carnian Alps, north-eastern Italy, which has affected a national road and seriously damaged a road tunnel still under construction. Moreover, since the landslide is located on the left bank of the Tagliamento River Valley, it is feared that this mass movement might dam the river, creating a basin that would increase natural hazard for the valley inhabitants. The data collected from December 2002 to July 2005 by a conventional monitoring system, consisting of a GPS network and boreholes equipped with inclinometric tubes, showed that the landslide was moving at a quasi-constant rate of about 3 cm per year. Due to the slow deformation rate of the landslide, a recently developed GB-SAR technique based on the analysis of a restricted ensemble of coherent points was used. Two surveys, each lasting two days, were planned in December 2004 and July 2005, in order to map and measure the surface displacements that occurred over time. The results from the radar were compared with the ones derived from the GPS monitoring network. An agreement was achieved among the data collected, showing the capability of the GB-SAR technique to measure displacements even within a time span of several months between the surveys.  相似文献   

Kinematic and geochronological constraints on shear deformation in the Ferriere-Mollières shear zone (Argentera-Mercantour Massif,Western Alps): implications for the evolution of the Southern European Variscan Belt     

Simonetti  Matteo  Carosi  Rodolfo  Montomoli  Chiara  Langone  Antonio  D’Addario  Enrico  Mammoliti  Elisa 《International Journal of Earth Sciences》2018,107(6):2163-2189

International Journal of Earth Sciences - In the Western Alps, a steeply dipping km-scale shear zone (the Ferriere-Mollières shear zone) cross-cuts Variscan migmatites in the...  相似文献   

Local Habitat and Seascape Structure Influence Seagrass Fish Assemblages in the Venice Lagoon: The Importance of Conservation at Multiple Spatial Scales     

Luca Scapin  Matteo Zucchetta  Adriano Sfriso  Piero Franzoi 《Estuaries and Coasts》2018,41(8):2410-2425

  相似文献   

Correction to: A novel methodological approach for land subsidence prediction through data assimilation techniques     

Gazzola  Laura  Ferronato  Massimiliano  Frigo  Matteo  Janna  Carlo  Teatini  Pietro  Zoccarato  Claudia  Antonelli  Massimo  Corradi  Anna  Dacome  Maria Carolina  Mantica  Stefano 《Computational Geosciences》2021,25(5):1751-1751

Computational Geosciences - A Correction to this paper has been published: https://doi.org/10.1007/s10596-021-10079-6  相似文献   

Shaking table tests of a full-scale flat-bottom manufactured steel silo filled with wheat: Main results on the fixed-base configuration     

Stefano Silvestri  Sulyman Mansour  Matteo Marra  Johann Distl  Marco Furinghetti  Igor Lanese  Enrique Hernndez-Montes  Caterina Neri  Michele Palermo  Alberto Pavese  Elisa Rizzo Parisi  Adam Jan Sadowski  Francesco Selva  Tomoyo Taniguchi  Laura Vadrucci  Felix Weber 《地震工程与结构动力学》2022,51(1):169-190

This paper reports on a series of shaking table tests on a full-scale flat-bottom steel silo filled with soft wheat, characterized by aspect ratio of around 0.9. The specimen was a 3.64-m diameter and 5.50-m high corrugated-wall cylindrical silo. Multiple sensors were used to monitor the static and dynamic response of the filled silo system, including accelerometers and pressure cells. Numerous unidirectional dynamic tests were performed consisting of random signals, sinusoidal inputs, and both artificial and real earthquake records. The objectives of this paper are (i) to provide a general overview of the whole experimental campaign and (ii) to present selected results obtained for the fixed-base configuration. The measured data were processed to assess the static pressures, the dynamic overpressures (related to the effective mass) and the accelerations of monitored points on the silo wall, and to identify the basic dynamic properties (fundamental frequency of vibration, damping ratio, dynamic amplification factors) of the filled silo. The main findings are discussed and compared with the predictions given by available theoretical models and code provisions. It is found that the fundamental frequency slightly decreases with increasing acceleration, while it slightly increases with increasing compaction of the granular material. For close-to-resonance input, the dynamic amplification (in terms of peak values of accelerations) increases along the height of the silo wall up to values of around 1.4 at the top surface of the solid content. The dynamic overpressures appear to increase with depth (differently from the EN1998-4 expectations), and to be proportional to the acceleration.  相似文献   

Empirical relationships for estimating stream depletion by a well pumping near a gaining stream   总被引：1，自引：0，他引：1  

Di Matteo L  Dragoni W 《Ground water》2005,43(2):242-249

Siting wells near streams requires an accurate estimate of the quantity of water derived from the river due to pumping. A number of hydrogeological and hydraulic parameters influence this value. This study estimates stream depletion under steady-state conditions for a variety of hydrogeological systems. A finite differences model was used to analyze several hydrogeological situations, and for each of these the stream depletion was estimated using an advective transport method. An empirical equation for stream depletion was obtained for the case of a stream that partially penetrates the aquifer and a pumping well that is screened over a portion of the aquifer. The derived equation, which is valid for both isotropic and anisotropic conditions, expresses stream depletion as a function of the unit inflow to the river, the discharge of the pumping well, the well screen length, the distance between the river and pumping well, the wetted perimeter, and a new parameter called "overlap," which is defined to be the distance between the riverbed and the top of well screen. The overlap parameter makes it possible to consider indirectly the vertical component of flow, which is accentuated when the well is screened below the streambed. The formula proposed here should be useful in deciding where to locate a pumping well and to decide the appropriate length of its screen.  相似文献