366 research outputs found
Pericolosita' sismica della Sicilia sud orientale terremoti di scenario per Augusta, Siracusa e Noto
No full textLa ricerca illustrata ha come obiettivo fondamentale la stima dei Terremoti di Scenario ad Augusta, Siracusa e Noto mediante l’applicazione di approcci di tipo ingegneristico con criteri deterministici
Beno Gutenberg contribution to seismic hazard assessment and recent progress in the European-Mediterranean region
No full textThe fundamental work of Beno Gutenberg has inspired and guided an appreciable part of research in modern seismology, both from the experimental and the theoretical point of view. Among the several topics of seismology that have benefited from the fundamental contribution of Gutenberg, we consider particularly relevant the description of the asthenospheric low-velocity channel, the definition of the surface waves magnitude and the Gutenberg–Richter law, since they are pivotal tools for seismic hazard assessment.
The quite revolutionary model for the lithosphere–asthenosphere system in the European area predicts the existence of almost aseismic lithospheric roots. These roots are located in correspondence of most of the orogenic belts and interrupt the asthenosphere low velocity channel that has been identified by Beno Gutenberg in 1948. The model of the European upper mantle, proposed for the first time in 1979 and subsequently refined, has stimulated a considerable amount of research, which has nicely confirmed the major innovative features of the early model. At present, the subduction of the lithosphere at continent–continent collisions, supported not only by seismological data, is a widely accepted concept within the community of Earth scientists, even if it contradicts one of the basic dogmas of the original formulation of plate tectonics. The proposed model for the Alpine–Apennines area supplies a new and unifying framework for the interpretation of the Quaternary magmatism, at present generally accepted by petrologists and geochemists.
The theoretical basis for the Gutenberg’s surface-wave magnitude calibration function has been supplied by the use of complete synthetic seismograms, and thus it has been possible to formulate the theoretical MS depth correction. The introduction of the depth correction for MS enables the computation of surface wave magnitude for all earthquakes, regardless of their focal depth. This is especially important for the quantification of subcrustal historical earthquakes, for which the seismic moment may be difficult to estimate from recordings of early mechanical seismographs. The new MS calibrating function yield both distance- and depth-independent magnitude estimates.
The analysis of the global seismicity, using the seismotectonic regionalization in subduction zones, mid oceanic ridge zones, island arcs, shows that a single Gutenberg–Richter ŽGR. relation is not universally applicable and that a multiscale seismicity model can reconcile two apparently conflicting paradigms: the Self-Organized Criticality mechanism and the Characteristic Earthquake concept. The multiscale representation has been applied to Italy, where the zones at the space scale of 400–500 km quite well reproduce the shapes of the regions used to apply the, globally tested, CN intermediate term
earthquake prediction algorithm. q2001 Elsevier Science B.V. All rights reserved
Scenario based assessment of seismic hazard: A must for the effective protection of historical buildings.
No full textSeismic waves in 3-D: from mantle asymmetries to reliable seismic hazard assessment.
No full textA global cross-section of the Earth parallel to the tectonic equator (TE) path, the great circle representing the equator of net lithosphere rotation, shows a difference in shear wave velocities between the western and eastern flanks of the three major oceanic rift basins. The low-velocity layer in the upper asthenosphere, at a depth range of 120 to 200 km, is assumed to represent the decoupling between the lithosphere and the underlying mantle. Along the TE-perturbed (TE-pert) path, a ubiquitous LVZ, about 1,000-km-wide and 100-km-thick, occurs in the astheno-sphere. The existence of the TE-pert is a necessary pre-requisite for the existence of a continuous global flow within the Earth. Ground-shaking scenarios were con-structed using a scenario-based method for seismic hazard analysis (NDSHA), using realistic and duly validated synthetic time series, and generating a data bank of several thousands of seismograms that account for source, propa-gation, and site effects. Accordingly, with basic self-organized criticality concepts, NDSHA permits the inte-gration of available information provided by the most updated seismological, geological, geophysical, and geo-technical databases for the site of interest, as well as advanced physical modeling techniques, to provide a reli-able and robust background for the development of a design basis for cultural heritage and civil infrastructures. Estimates of seismic hazard obtained using the NDSHA and standard probabilistic approaches are compared for the Italian territory, and a case-study is discussed. In order to enable a reliable estimation of the ground motion response to an earthquake, three-dimensional velocity models have to be considered, resulting in a new, very efficient, ana-lytical procedure for computing the broadband seismic wave-field in a 3-D anelastic Earth model
Comunione di nuda proprietà
No full textL'Autore ricostruisce la disciplina applicabile nel caso di comunione di nuda proprietà, analizzando i poteri, le facoltà, i diritti e gli obblighi spettanti ai contitolari del diritto reale
Il cousufrutto
No full textL'Autore dopo aver analizzato la disciplina applicabile alla comunione di usufrutto si sofferma sulle figure del cousufrutto dei genitori sui beni del minore, dell'usufrutto congiuntivo, e dell' acquisto di usufrutto da parte di uno dei coniugi in costanza di comunione legale
Comunione di servitù
No full textL'Autore affronta il problema della configurabilità di una comunione del diritto reale di servitù stante il carattere di indivisibilità di tale diritto
La coenfiteusi
No full textNel contributo l'Autore analizza e ricostruisce la disciplina applicabile nel caso di comunione del diritto di enfiteusi
Seismic wave propagation in laterally heterogeneous anelastic media: Theory and applications to seismic zonation
No full textSeismic wave propagation in laterally heterogeneous anelastic media: Theory and applications to seismic zonatio
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