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Seismic hazard for critical facilities
No full textCritical facilities are man-made equipments, plants, constructions, and
structures that, if affected by a strong earthquake, can produce serious
impacts on people, environment, and economy. Therefore, for these
facilities specific provisions in terms of seismic design are required
and detailed seismic hazard evaluations have to be developed. In this
paper, firstly the concept and meaning of ``critical facilities'' is
argued. Then, a focus on the seismic hazard of nuclear power plants is
presented since this type of critical facilities could be considered the
facilities that more than others have contributed to define the most
advanced knowledge in the field of seismic hazard assessment
The seismic sequence of Friuli 76: new seismotectonic aspects
No full textMost of the seismological data recorded during the first year of
the seismic sequence that struck Friuli in 1976 have been collected
and elaborated with a standard approach. A good quality data set of
291 hypocentral locations and 101 fault plane solutions has been
obtained and used for checking the seismogenic interpretation, and
some vertical cross-sections representing a quantity, the hypocentral
probability, which takes into account the errors in the locations have
been constructed. These sections show two high probability volumes:
one is gently north-dipping and the second is steeply southdipping.
The fault plane solutions have been projected, with the correct
space rotation, onto the sections, and their nodal planes are in
agreement with both elongations of the hypocentral probability volume.
These elaborations put under a different light the traditional
seismotectonic interpretation of the seismic sequence. On the basis
of new geological data, a 2D structural model for the frontal sector
of the Southalpine chain has been constructed. According to the
classical tectonic setting suggested for the Eastern Southalpine
chain, the cross-section shows a S-vergent thrust-belt arranged in an
embricate fan geometry. Nevertheless, at the Gemona latitude, at a
depth of 5-8 km, a N-vergent steep backthrusting system becomes
active producing a local thickening of rigid carbonatic rocks: part of
the cracks of the sequence seems to concentrate here
Caratterizzazione della danneggiabilità sismica di infrastrutture critiche lineari: il caso dell’oleodotto in Friuli Venezia Giulia
No full textNew seismotectonic evidence from the analysis of the 1976-1977 and 1977-1999 seismicity in Friuli (NE Italy)
No full textCharacterization of the expected seismic damage for a critical infrastructure: the case of the oil pipeline in Friuli Venezia Giulia (NE Italy)
No full textSeismic codes using the performance-based approach for seismic design of critical and important structures generally refer to seismic hazard which takes into account a lower exceedance probability than that used for ordinary buildings. In the present study, the seismic hazard for an oil pipeline, located in the Friuli Venezia Giulia region (NE Italy), has been calculated in terms of PGA and PGV with a 2475-year return period, and compared with estimates calculated with the standard 475-year return period used for ordinary buildings. The results, referring to three soil types (rock, stiff soil, and soft soil), have been combined through GIS technology in a single map (soil seismic hazard map) on the basis of the local lithological characterization. The major earthquakes considered in the study have been associated with the linear sources found in the database of Italian seismic sources, considering the characteristic earthquake model. The regional seismogenic zonation has been added to the linear sources in order to consider minor seismicity as described by the Gutenberg-Richter model. Quaternary faults in the broader Trieste area, long enough to justify, at least, a characteristic magnitude of 6, have been added in the source model to take into account unlikely but possible unknown sources. The Transalpine Oil Pipeline, which connects Trieste (Italy) to Ingolstadt (Germany), is the crude-oil distribution system considered in the present study. It consists of a storage tank, compressor stations, and buried pipeline. For the characterization of the expected damage to the infrastructure in case of an earthquake, we have used underground pipeline seismic vulnerability curves that relate a performance indicator, such as the reparation rate (number of ruptures per kilometre), with a representative ground motion parameter (e.g., PGA or PGV). In this study, we have considered as performance indicator the consequences of a rupture in the pipeline caused by a seismic event
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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