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1.
Sauermilch Isabel Mateo Zenon Richard P. Boaga Jacopo 《Marine Geophysical Researches》2019,40(4):635-641
Marine Geophysical Research - Time–depth relationships (TDR) are required for correlating geological information from drill sites with seismic reflection profiles. Conventional... 相似文献
2.
Large landslides and deep-seated gravitational slope deformations (DSGSD) represent an important geo-hazard in relation to the deformation of large structures and infrastructures and to the associated secondary landslides. DSGSD movements, although slow (from a few millimetres to several centimetres per year), can continue for very long periods, producing large cumulative displacements and undergoing partial or complete reactivation. Therefore, it is important to map the activity of such phenomena at a regional scale. Ground surface displacements at DSGSD typically range close to the detection limit of monitoring equipment but are suitable for synthetic aperture radar (SAR) interferometry. In this paper, permanent scatterers (PSInSAR?) and SqueeSAR? techniques are used to analyse the activity of 133 DSGSD, in the Central Italian Alps. Statistical indicators for assigning a degree of activity to slope movements from displacement rates are discussed together with methods for analysing the movement and activity distribution within each landslide. In order to assess if a landslide is active or not, with a certain degree of reliability, three indicators are considered as optimal: the mean displacement rate, the activity index (ratio of active PS, displacement rate larger than standard deviation, overall PS) and the nearest neighbor ratio, which allows to describe the degree of clustering of the PS data. According to these criteria, 66% of the phenomena are classified as active in the monitored period 1992–2009. Finally, a new methodology for the use of SAR interferometry data to attain a classification of landslide kinematic behaviour is presented. This methodology is based on the interpretation of longitudinal ground surface displacement rate profiles in the light of numerical simulations of simplified failure geometries. The most common kinematic behaviour is rotational, amounting to 41 DSGSDs, corresponding to the 62.1% of the active phenomena. 相似文献
3.
The day–night cycle is one of the strongest geophysical cycles modulating species' behavioral rhythms. However, in deep-water continental margins, where light intensity decreases over depth, interspecific competition may alter behavioral responses to day–night cycles. The burrowing decapod crustacean Nephrops norvegicus is a large-size predator in benthic communities, exerting despotic territorial behavior. In this study, we analysed how the effect of light intensity cycles on decapod behavioral rhythms is reduced as one moves from shelves to slopes. In the Western Mediterranean, the predatory behavior and interspecific competition for substrate use of Nephrops increases moving from the shelf (100–110 m) to the slope (400–430 m). Vector fitting and generalized additive models were used to assess the effect of light intensity and behavioral rhythms of N. norvegicus on the temporal variation of prey decapods co-occurring in trawl tow catches carried out on the shelf and the slope during October 1999 and June 2000. The combination of diel variations in light intensity and N. norvegicus abundance influences the activity rhythms of prey decapods in a depth- and seasonal-dependent manner. Light modulation is stronger on the shelf and weaker on the slope, where Nephrops population size is greater. Although present regression analysis does not necessarily imply a direct cause–effect relationship between rhythms of predators and prey, we suggest that Nephrops alters the temporal patterning in the behavior of its prey on the slope, where light intensity is reduced. This alteration is stronger in endobenthic species than in benthopelagic species; the former rely on bottom substrate for the expression of behavioral rhythms, experiencing stronger interspecific competitions with Nephrops at time of activity. 相似文献
4.
Rock fall hazard zoning is a challenging yet necessary task to be accomplished for planning an appropriate land use in mountainous areas. Methodologies currently adopted for elaborating zoning maps do not provide satisfactory results though, due to uncertainties and related assumptions characterising hazard assessment. The new Cadanav methodology, presented in this paper, aims at improving quantitative hazard assessment and zoning at the local scale, by reducing uncertainties mainly related to the technique for combining rock fall intensity and frequency of occurrence. Starting from available information on rock fall failure frequency and trajectory simulation results, the procedure merges in a strict way temporal frequency, probability of reach and energy data and evaluates the hazard degree by means of “hazard curves”. These curves are described at each point of the slope by a series of energy–return period couples representing the hazardous conditions which may possibly affect that location. The new Cadanav methodology is here detailed and compared to its original version. Hazard zoning results are illustrated along two different 2D slope profiles, for linear homogeneous cliff configurations, and according to the Swiss intensity–frequency diagram for rock fall hazard zoning. However, the procedure can be easily used with any other intensity–frequency diagram prescribed in national guidelines and, additionally, extended to problems involving 3D topographies. 相似文献
5.
Carmela Freda Mario Gaeta Daniel B. Karner Fabrizio Marra Paul R. Renne Jacopo Taddeucci Piergiorgio Scarlato John N. Christensen Luigi Dallai 《Bulletin of Volcanology》2006,68(6):567-591
A comprehensive volcanological study of the Albano multiple maar (Alban Hills, Italy) using (i) 40Ar/39Ar geochronology of the most complete stratigraphic section and other proximal and distal outcrops and (ii) petrographic observations,
phase analyses of major and trace elements, and Sr and O isotopic analyses of the pyroclastic deposits shows that volcanic
activity at Albano was strongly discontinuous, with a first eruptive cycle at 69±1 ka producing at least two eruptions, and
a second cycle with two peaks at 39±1 and 36±1 ka producing at least four eruptions. Contrary to previous studies, we did
not find evidence of magmatic or hydromagmatic eruptions younger than 36±1 ka. The activity of Albano was fed by a new batch
of primary magma compositionally different from that of the older activity of the Alban Hills; moreover, the REE and 87Sr/86Sr data indicate that the Albano magma originated from an enriched metasomatized mantle. According to the modeled liquid line
of descent, this magma differentiated under the influence of magma/limestone wall rock interaction. Our detailed eruptive
and petrologic reconstruction of the Albano Maar evolution substantiates the dormant state of the Alban Hills Volcanic District.
Electronic Supplementary Material Supplementary material is available for this article at
Editorial responsibility: J. Donnelly-Nolan
An erratum to this article can be found at 相似文献
6.
7.
Dynamics of the circulation in the Sea of Marmara: numerical modeling experiments and observations from the Turkish straits system experiment 总被引：4，自引：3，他引：1
Jacopo?ChiggiatoEmail author Ewa?Jarosz Jeffrey?W.?Book James?Dykes Lucio?Torrisi Pierre-Marie?Poulain Riccardo?Gerin Jochen?Horstmann ?ükrü?Be?iktepe 《Ocean Dynamics》2012,62(1):139-159
During September 2008 and February 2009, the NR/V Alliance extensively sampled the waters of the Sea of Marmara within the
framework of the Turkish Straits System (TSS) experiment coordinated by the NATO Undersea Research Centre. The observational
effort provided an opportunity to set up realistic numerical experiments for modeling the observed variability of the Marmara
Sea upper layer circulation at mesoscale resolution over the entire basin during the trial period, complementing relevant
features and forcing factors revealed by numerical model results with information acquired from in situ and remote sensing
datasets. Numerical model solutions from realistic runs using the Regional Ocean Modeling System (ROMS) produce a general
circulation in the Sea of Marmara that is consistent with previous knowledge of the circulation drawn from past hydrographic
measurements, with a westward meandering current associated with a recurrent large anticyclone. Additional idealized numerical
experiments illuminate the role various dynamics play in determining the Sea of Marmara circulation and pycnocline structure.
Both the wind curl and the strait flows are found to strongly influence the strength and location of the main mesoscale features.
Large displacements of the pycnocline depth were observed during the sea trials. These displacements can be interpreted as
storm-driven upwelling/downwelling dynamics associated with northeasterly winds; however, lateral advection associated with
flow from the Straits also played a role in some displacements. 相似文献
8.
Jacopo Taddeucci Gianluca Sottili Danilo M. Palladino Guido Ventura Piergiorgio Scarlato 《Bulletin of Volcanology》2010,72(1):75-83
Hydromagmatic eruptions convert thermal into mechanical energy via the expansion of ground- and/or surface-water. Several
models address the energetics of these eruptions based on different physical-volcanological approaches. Here we test different
models with two case studies in the Colli Albani Volcanic District (central Italy): the monogenetic Prata Porci and the polygenetic
Albano maars. Test results are mutually consistent, and show cumulative mechanical energy releases on the order of 1015–1017 J for single maars. The fraction of thermal energy turned into mechanical ranges from 0.45 (as calculated from the theoretical
maximum mechanical energy), through 0.1 (calculated from country rock fragmentation, crater formation and ballistic ejection),
to 0.03 (derived from magma fragmentation by thermohydraulic explosions). It appears that the energy released during the most
intense hydromagmatic events may account for a dominant fraction of the total mechanical energy released during the whole
maar eruptive histories. Finally, we consider the role of magmatic explosive activity intervening during maar eruptions in
causing departures from predictions of the models evaluated. 相似文献
9.
BET_VH: exploring the influence of natural uncertainties on long-term hazard from tephra fallout at Campi Flegrei (Italy) 总被引：2，自引：0，他引：2
Jacopo Selva Antonio Costa Warner Marzocchi Laura Sandri 《Bulletin of Volcanology》2010,72(6):717-733
In this paper, we explore the effects of the intrinsic uncertainties upon long-term volcanic hazard by analyzing tephra fall
hazard at Campi Flegrei, Italy, using the BET_VH model described in Marzocchi et al. (Bull Volcanol, 2010). The results obtained show that volcanic hazard based on the weighted average of all possible eruptive settings (i.e. size
classes and vent locations) is significantly different from an analysis based on a single reference setting, as commonly used
in volcanic hazard practice. The long-term hazard map for tephra fall at Campi Flegrei obtained here accounts for a wide spectrum
of uncertainties which are usually neglected, largely reducing the bias intrinsically introduced by the choice of a specific
reference setting. We formally develop and apply a general method to recursively integrate simulations from different models
which have different characteristics in terms of spatial coverage, resolution and physical details. This outcome of simulations
will be eventually merged with field data through the use of the BET_VH model. 相似文献
10.
This paper proposes a new methodological approach to silted reservoir management and defence, which combines the reservoir rehabilitation process and the utilization of the recovered water volumes and sediments. This approach, strategic from both the economical and environmental points of view, is here defined as Economic Environmental Defence (EED) of a reservoir. The EED approach is applied to the case study of Guardialfiera reservoir, where the available experimental data allowed the estimation of silta-tion up to date, the analysis of the distribution of sediment particle size along the reservoir bottom and the possibility to propose a feasible utilization of water and sediments resulting from the reservoir rehabilitation. 相似文献