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Now showing items 1 - 16 of 27

  • Sediment texture in rock avalanche deposits:insights from field and experimental observations

    Schiliro, L.   Esposito, C.   De Blasio, F. V.   Mugnozza, G. Scarascia  

    Sedimentary structures within rock avalanche deposits have gained increasing attention in recent years, since they may provide useful information about the dynamics of such energetic events. This work then is aimed at better defining the physical processes arising during the propagation, paying particular attention to the kinetic sieving mechanism, and strengthening the assumption (widely diffused in the literature) that such a process does not occur for similar events. Specifically, after the examination of two rock avalanche deposits in Central Italy, where cuts through the fragmented deposits are accessible and illustrative of the sediment texture, a series of laboratory flume tests have been performed in order to investigate in detail the flowing process. A simplified physical model for granular agitation has been then introduced to explain how and why kinetic sieving may occur at the laboratory scale and, in the case of natural granular flows of reduced size, also at the field scale.
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  • The geological model of Celano town area for seismic microzonation activities RID D-3848-2009

    Fasani, G. Bianchi   Cavinato, G. P.   Petitta, M.   Mugnozza, G. Scarascia   Voltaggio, M.  

    In this paper are presented the results of integrated investigations aimed at building a reference geological model for the seismic microzonation of Celano municipality (Central Italy). The study area is located along the northern rim of the Fucino basin, which is an intermontane half-graben filled by thick Plio-Quaternary alluvial and lacustrine deposits and is surrounded by Meso-Cenozoic limestone and Neogene sandstone relieves, with mean elevation around 1500m a.s.l., that also represent the bedrock units of the basin itself. Evidences of recent tectonic activity within the Fucino basin have been pointed out by several paleoseismological studies recently performed to better frame the effects of the seismogenic structures responsible for the Ms 7.0, 1915 Avezzano earthquake and other historical and prehistoric seismic events occurred in the area. On the basis of integrated site and laboratory investigations, such as surface geological surveys, borehole logging, isotope geochemical analyses based on Th-230/U-234 dating method, geotechnical investigation and hydrogeological prospecting, the geological model of the area was built. The identification of such model was fundamental in view of correct planning and development of further investigations and analyses, mainly based on geophysical methods and seismic response modelling, carried out by other research teams cooperating within the Celano seismic microzonation project. (C) 2008 Elsevier Ltd. All rights reserved.
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  • Expression of Aux/IAA genes during development of sylleptic and proleptic buds in white poplar

    Terzoli, S.   Beritognolo, I.   Giovannelli, A.   Benelli, C.   Migliaccio, F.   Piconese, S.   Sabatti, M.   Kuzminsky, E.   Mugnozza, G. Scarascia  

    In this study, the genes of the Aux/IAA family were used as functional markers to characterise bud break stages in a white poplar clone. In the first experiment, under greenhouse conditions, the sprouting of repressed sylleptic buds was obtained by pruning the shoot tip during growing season. Buds were collected at 0, 6, 24 and 48 h after pruning for molecular analyses. A decrease in transcript level of IAA4 and IAA8 genes was observed in the first and second bud below the cut after 6 and 24 h, respectively. In the second experiment, bud break of post-dormant proleptic buds was induced by forcing in climatic chamber. The first 6 and the following 6 buds below the apical one were sampled every 48 h during forcing. Anatomical studies were also carried out on buds and plants were equipped with stem and bud radial growth sensors to check their swelling. In both experiments, gene expression patterns showed a decrease and a successive increase in expression of IAA4 and IAA8 genes during bud break. The transient down-regulation of these genes was observed only in buds that formed new branches. Thus, similar molecular mechanisms are involved in bud break of both sylleptic and proleptic buds.
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  • Earthquake-reactivated landslide scenarios in Southern Italy based on spectral-matching input analysis

    Bozzano, F.   Esposito, C.   Martini, G.   Martino, S.   Prestininzi, A.   Rinaldis, D.   Romeo, R. W.   Mugnozza, G. Scarascia  

    The Tyrrhenian portion of the Calabria region (southern Italy) is particularly prone to landslides as a consequence of intense morphodynamic processes. These processes affect the slopes that are composed of highly jointed metamorphic rock masses. Moreover, the frequent intense rainfalls and the up to Mw 7.0 regional earthquakes represent the main landslide triggering factors. An area of approximately was selected as a test site in the context of a regional project aimed at reconstructing possible earthquake-reactivated landslide scenarios (i.e., referred to already existing landslide masses). An inventory map led to the identification of 175 landslides, including rock slides, earth slides and rock falls. Ground-motion scenarios based on a spectral-matching method were derived to evaluate the expected earthquake-induced displacements of the existing landslides. Naturally recorded acceleration time histories were selected from international ground-motion databases based on a similarity index and considered representative of the seismological features of the considered seismic sources (i.e., epicentral distance, magnitude, focal mechanism). Spectral attenuation was considered, according to well-established attenuation laws, to define the expected response spectrum at the outcropping bedrock corresponding to each existing landslide. Subsequently, the selected natural records were modified to guarantee spectral matching with the attenuated response spectra at each landslide site. The derived time histories were used to compute co-seismic displacements via the classic Newmark's sliding-block method. Different scenarios of co-seismic landslide displacements or collapse were generated for different pore-water pressure hypotheses. The strongest seismic scenario (Messina Straits seismogenic source) indicated an exceedance probability of earthquake-induced co-seismic landslide collapse varying from 20 to 55 % with the increasing severity of the pore-water pressures. This probability corresponds to a percentage of co-seismic landslide displacements up to 40 % of the total inventoried landslides. The exceedance probability indicated that co-seismic landslide collapse drops below 20 % for seismic scenarios. In contrast, if a uniform probability is assumed for the seismic action occurrence, i.e., return periods of 475 and 2,475 years, the total percentage of landslide co-seismic displacements could be as high as 70 and 90 %, respectively, for the considered pore-water pressures.
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  • Testing of models of stomatal ozone fluxes with field measurements in a mixed Mediterranean forest

    Matteucci, G.   Mugnozza, G. Scarascia   Morani, A.   Calfapietra, C.   Salvatori, E.   Fusaro, L.   Manes, F.   Loreto, F.  

    Mediterranean forests close to urban areas are exposed to polluted plumes loaded with tropospheric ozone. This is the case of Castelporziano Estate, a 6000 ha Mediterranean forest 25 km from Rome downtown on the coast of the Mediterranean Sea. In September 2011 we started an intensive field campaign aimed at investigating ozone deposition from a mixed Mediterranean forest, mainly composed by Quercus suber, Quercus ilex, Pinus pinea. Measurements at canopy level with the eddy covariance technique were supported by a vegetation survey and the measurement of all environmental parameters which allowed to calculate stomatal ozone fluxes. Leaf-level measurements were used to parameterize models to calculate stomatal conductance based on a Jarvis-type and Ball-Berry approach. We show changes in magnitude of ozone fluxes from a warm (September) to a cold period (October December). Stomatal component explained almost the totality of ozone fluxes during the cold days, but contributed only up to 50% to total ozone deposition during warm days, suggesting that other sinks (e.g. chemistry in the gas-phase) play a major role. Modeled stomatal ozone fluxes based on a Jarvis-type approach (DO3SE) correlated with measured fluxes better than using a Ball-Berry approach. A third model based on a modified Ball-Berry equation was proposed to account for the non-linear dependency of stomatal conductance on relative humidity. This research will help the development of metrics for ozone-risk assessment and advance our understanding of mixed Mediterranean forests in biosphere atmosphere exchange. (C) 2012 Elsevier Ltd. All rights reserved.
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  • The Role of Initial Soil Conditions in Shallow Landslide Triggering:Insights from Physically Based Approaches

    Schiliro, L.   Djueyep, G. Poueme   Esposito, C.   Mugnozza, G. Scarascia  

    In the last years, the shallow landslide phenomenon has increasingly been investigated through physically based models, which try to extend over large-area simplified slope stability analyses using physical and mechanical parameters of the involved material. However, the parameterization of such models is usually challenging even at the slope scale, due to the numerous parameters involved in the failure mechanism. In particular, considering the scale of the phenomenon, the role of transient hydrology is essential. For this reason, in this work we present the outcome of different experimental tests conducted on a soil slope model with a sloping flume. The tested material was sampled on Monte Mario Hill (Rome, Central Italy), an area which has been frequently affected by rainfall-induced landslide events in the past. In this respect, we also performed a physically based numerical analysis at the field conditions, in order to evaluate the response of the terrain to a recent extreme rainfall event. The results of the flume tests show that, for the same material, two different triggering mechanisms (i.e., uprise of a temporary water table and advance of the wetting front) occur by varying the initial water content only. At the same time, the results of the numerical simulations indicate that clayey sand and lean clay are the soil types mostly influenced by the abovementioned rainfall event, since the initial moisture conditions enhance the formation of a wide wetting front within the soil profile.
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  • Flash-flood hyperpycnal flows generating shallow-water landslides at Fiumara mouths in Western Messina Strait (Italy)

    Casalbore, D.   Chiocci, F. L.   Mugnozza, G. Scarascia   Tommasi, P.   Sposato, A.  

    On October 1, 2009, a small area along the Sicilian coast between the villages of Scaletta Zanclea and Giampilieri was struck by intense and concentrated rainfall causing countless small landslides widespread over the catchment area of steep subaerial creeks, locally known as Fiumara. Dense and quick debris flows were channelized within the Fiumara and destructively hit the villages and entered the sea, where they likely transformed into hyperpycnal flows. The availability of pre- and post-flood high-resolution bathymetry allows us to recognize the main features and the most significant morphological variations related to the impact of the flows on the seafloor. The passage of hyperpycnal flows on the seafloor possibly produced a suite of mass-wasting events, encompassing sheet landslides (i.e. erosive scours), retrogressive slope failure on loose sediment at the canyon headwall and rock-falls on the conglomeratic bedrock along canyon sidewall. The possible causes of these events are discussed on the basis of available morphological evidence and geotechnical considerations. Finally, the widespread occurrence of mass-wasting features (i.e. submarine landslide scars) morphologically similar to those generated by the 2009 flash flood allows us to hypothesize, from one side, a strong correlation between this catastrophic event and the evolution of submarine canyons, and from the other side, the possible use of these features for the assessment of flash-flood occurrence.
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  • The role of near-field interaction between seismic waves and slope on the triggering of a rockslide at Lorca (SE Spain)

    Alfaro, P.   Delgado, J.   Garcia-Tortosa, F. J.   Giner, J. J.   Lenti, L.   Lopez-Casado, C.   Martino, S.   Mugnozza, G. Scarascia  

    A similar to 1000 m(3) rockslide occurred close to Lorca ( SE Spain) during the main shock (M-w = 5.1) of the May 2011 seismic sequence. The location of the rockslide, within 10 km of the earthquake epicenter and along the southern slope of a valley in which similar geological conditions occur on both slopes of the valley, suggests a significant near-field effect due to local seismic response. This could be related to the specific interaction between the topography and the obliquely propagating seismic waves. A dynamic stress strain numerical model was constructed using the FLAC 7.0 finite difference code to back analyze the Lorca rockslide event and relate its occurrence to both the local seismic amplification and the interaction between seismic waves and local topography. The results indicate that only for seismic waves with incidence angles in the range 0 degrees - 50 degrees are the occurred slope instabilities expected. These results do not significantly change when varying the values for either stiffness or strength parameters within the range of the experimental data.
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  • The gravitational slope deformation of Mt. Rocchetta ridge (central Apennines, Italy): geological-evolutionary model and numerical analysis

    Discenza, M. E.   Esposito, C.   Martino, S.   Petitta, M.   Prestininzi, A.   Mugnozza, G. Scarascia  

    This paper presents the results of a study on a deep-seated gravitational slope deformation affecting the eastern slope of the Mt. Rocchetta ridge (central Apennines, Italy). Fieldwork identified the ongoing deformational process and assisted in defining its mechanisms, evolution and controlling factors. An equivalent continuum approach was adopted to characterize the rock mass with some modification for the temporal and spatial scale of the process. A visco-elastic-plastic rheological model was adopted for the numerical analysis, which also took into account the groundwater flow feeding the Capo Volturno spring. The results of the numerical analysis are consistent with the observed geomorphic evidence and suggest a morpho-evolutionary model of the ridge characterized by an initial phase of rock mass creep followed by a rock mass spreading process, mainly controlled by the viscous behaviour but with a significant contribution from groundwater for the smaller scale instabilities.
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  • Evidence of Two-Dimensional Amplification Effects in an Alluvial Valley (Valnerina, Italy) from Velocimetric Records and Numerical Models RID D-3884-2009

    Lenti, L.   Martino, S.   Paciello, A.   Mugnozza, G. Scarascia  

    The results of field surveys, velocimetric records, and numerical models are reported with the goal of analyzing the local seismic response in a section of the Nera River alluvial valley in central Italy. Alluvial deposit geometry and dynamic properties were defined by geological and geophysical investigations. 2D amplification effects were pointed out by horizontal-to-vertical spectral ratios (HVSRs) as well as by horizontal-to-horizontal spectral ratios (HHSRs) to a reference station; HVSRs were derived from both noise and weak-motion records, while HHSRs were only computed from weak motions. Where travertine deposits are interlayered within the alluvia, 2D amplification effects are shown only by HHSRs. The observed amplifications: (1) consist of peaks of the amplification functions A (f) in the range 1-10 Hz, (2) generally correspond to two frequency ranges whose values mainly depend on the valley shaped ratio and on the local heterogenities of the alluvial deposits, and (3) can be regarded as due to a 1D resonance combined with lateral wave propagation. Numerical models via the finite difference method were performed by the Italian National Institute for Geophysics and Volcanology-Web Interface for Seismological Application and by the Fast Lagrangian Analysis of Continua codes. The obtained results: (1) show a good agreement with HHSRs, (2) prove that some 2D amplification effects are constrained by both the shape ratio of the valley and the heterogeneity of the alluvial deposits, (3) reveal focalization effects within the alluvial deposits strictly related to the shape of the valley, and (4) allow the comparison of the A(f) functions in both linear and nonlinear dynamic behavior and the computation of the shear strains due to ground motion within the alluvial deposits.
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  • The Contribution of Professor Gian Tommasso Scarascia Mugnozza to the Conservation and Sustainable Use of Biodiversity

    Pagnotta Mario   Noorani Arshiya  

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  • The Contribution of Professor Gian Tommasso Scarascia Mugnozza to the Conservation and Sustainable Use of Biodiversity

    Pagnotta, Mario Augusto   Noorani, Arshiya  

    During his lifetime, Professor Scarascia Mugnozza contributed significantly to the field of population genetics, his research ranging from wheat breeding in arid and semi-arid regions, to the conservation of forest ecosystems. He promoted regional networks across the Mediterranean, linking science and policy at national and international levels, focusing on the conservation and sustainable use of genetic diversity. In addition, he worked intensely on improvement of knowledge bases, raising awareness on how research could inform international agreements, and thus lead to evidence-based policies. The loss of biodiversity and the resulting implications for environmental, socio-economic, political, and ethical management of plant genetic resources were of major concern, and he highlighted the absolute necessity for conservation of genetic diversity, stressing the importance of building positive feedback linkages among ex situ, in situ, on-farm conservation strategies, and participatory approaches at the community level. His work emphasized the importance of access to diverse plant genetic resources by researchers and farmers, and promoted equitable access to genetic resources through international frameworks. Farmers' rights, especially those in centres of origin and diversity of cultivated plants, were a key concern for Professor Scarascia Mugnozza, as their access to germplasm needed to be secured as custodians of diversity and the knowledge of how to use these vital resources. Consequently, he promoted the development of North-South cooperation mechanisms and platforms, including technology transfer and the sharing of information of how to maintain and use genetic resources sustainably.
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  • Giantommaso Scarascia Mugnozza

    Giantommaso Scarascia Mugnozza  

    I shall begin with an issue with which we are engaged at this particular moment: the field of nutrition, which is also a topic in which the interaction between universities, public research organizations and industry should be enhanced.
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  • Giantommaso Scarascia Mugnozza

    Giantommaso Scarascia Mugnozza  

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  • Evaluation of shallow landslide-triggering scenarios through a physically based approach:an example of application in the southern Messina area (northeastern Sicily,Italy)

    Schiliro, L.   Esposito, C.   Mugnozza, G. Scarascia  

    Rainfall-induced shallow landslides are a widespread phenomenon that frequently causes substantial damage to property, as well as numerous casualties. In recent years a wide range of physically based models have been developed to analyze the triggering process of these events. Specifically, in this paper we propose an approach for the evaluation of different shallow landslide-triggering scenarios by means of the TRIGRS (transient rainfall infiltration and grid-based slope stability) numerical model. For the validation of the model, a back analysis of the landslide event that occurred in the study area (located SW of Messina, northeastern Sicily, Italy) on 1 October 2009 was performed, by using different methods and techniques for the definition of the input parameters. After evaluating the reliability of the model through comparison with the 2009 landslide inventory, different triggering scenarios were defined using rainfall values derived from the rainfall probability curves, reconstructed on the basis of daily and hourly historical rainfall data. The results emphasize how these phenomena are likely to occur in the area, given that even short-duration (1-3 h) rainfall events with a relatively low return period (e. g., 10-20 years) can trigger numerous slope failures. Furthermore, for the same rainfall amount, the daily simulations underestimate the instability conditions. The high susceptibility of this area to shallow landslides is testified by the high number of landslide/flood events that have occurred in the past and are summarized in this paper by means of archival research. Considering the main features of the proposed approach, the authors suggest that this methodology could be applied to different areas, even for the development of landslide early warning systems.
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  • Self-excitation process due to local seismic amplification responsible for the reactivation of the Salcito landslide (Italy) on 31 October 2002 RID D-3841-2009 RID D-3884-2009

    Bozzano, F.   Lenti, L.   Martino, S.   Paciello, A.   Mugnozza, G. Scarascia  

    An integrated numerical and geophysical approach was used to investigate the role of local seismic amplification in the reactivation of the Salcito landslide (Italy) after the Molise earthquake of 31 October 2002. Numerical stress-strain analysis with FLAC 5.0 FDM software, performed in dynamic configuration, showed that the 1 Hz frequency was consistent with landslide instability conditions. The Fourier spectrum of the triggering earthquake showed two main peaks occurring at 1 and 2 Hz, respectively, which could be related to local effects. The analysis of H/V spectral ratios of ambient noise records obtained in the landslide area, evidenced amplification effects in the 1-3 Hz range. On the basis of an engineering geology model, numerical modeling of both 1-D and 2-D seismic wave propagation was conducted using linear and nonlinear solutions. The simulation outputs showed (1) a 1 Hz amplification ascribable to 2-D effects due to a landslide mass lying within a basin-like geological structure; (2) a double-peak amplification at about 2 and 3 Hz, respectively, ascribable to 1-D resonance of the landslide mass; and (3) 1-D plus lateral wave effects within the landslide mass in the 2.5-3.5 Hz frequency range. These findings suggest that local amplification of ground motion by the Salcito landslide mass may generate a self-excitation process responsible for its reactivation.
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