1,720,971 research outputs found
Spectral and classical methods in the evaluation of Moho undulations from gravity data: the NE-Italian Alps and isostasy
No full textA review of the seismotectonics and some considerations on the seismic hazard of the Krško NPP area (SE Slovenia)
No full textThis paper gives short comments on the seismotectonic, seismological, and seismic hazard characteristics of the area of the nuclear power plant (NPP) of Krško (Slovenia). The plant was designed in the second half of the 1970s with no related probabilistic seismic hazard studies. The design was based on Regulatory Guides of 1973 with response spectra anchored to the peak ground acceleration of 0.30 g on the free field. The construction of a new NPP in the area is being taken into consideration by international investors. The Krško NPP is located inside a seismically active area, in which low-to-medium magnitude earthquakes have occurred in the last centuries. The greatest intensity felt near the NPP site was VIII for a local MW 5.7 - 6.2 earthquake in 1917, and the strongest event in the region was the M ≈ 6.3 Zagreb, 1880 event, whose epicentre was about 65 km from the NPP. The plant is close to some faults with unresolved neotectonic activity in the post-glacial epoch (18,000 years). Some stress test results from the 1990s would have suggested that 0.3 g were adopted at -20 m depth, corresponding to an effective value of 0.6 g at zero depth; this aspect is also commented. Finally, the difficult problem of estimating the maximum credible magnitude, Mmax, for very long return periods is addressed, based on the geological evidence provided by Geomatrix Consultants Inc. in 2004. From an apparent rupture length of 40 km of the Orlica fault, an Mmax of at least 7.2 could be hypothesized (1 st. dev. included). This hypothesis has anyway a low reliability, because the extent of the spatial continuity of the Orlica fault is still debated
Mapping long-period soil resonances in the Kathmandu basin using microtremors
Get PDFThis study reports the geostatistical analysis of a set of 40 single-station horizontal-to-vertical spectral ratio (HVSR) passive seismic survey data collected in the Kathmandu basin (Nepal). The Kathmandu basin is characterized by a heterogeneous sedimentary cover and by a complex geo-structural setting, inducing a high spatial variability of the bedrock depth. Due to the complex geological setting, the interpretation and analysis of soil resonance periods derived from the HVSR surveys is challenging, both from the perspective of bedrock depth estimation as well as of seismic-site effects characterization. To exploit the available information, the HVSR data are analyzed by means of a geostatistical approach. First, the spatial continuity structure of HVSR data is investigated and interpreted taking into consideration the geological setting and available stratigraphic and seismic information. Then, the exploitation of potential auxiliary variables, based on surface morphology and distance from outcropping bedrock, is evaluated. Finally, the mapping of HVSR resonance periods, together with the evaluation of interpolation uncertainty, is obtained by means of kriging with external drift interpolation. This work contributes to the characterization of local seismic response of the Kathmandu basin. The resulting map of soil resonance periods is compatible with the results of preceding studies and it is characterized by a high spatial variability, even in areas with a deep bedrock and long resonance periods
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Parametri di sorgente dei terremoti di Ljubljana (Slovenia) del 1895 e del 1897 dalla inversione di dati macrosismici
No full textVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Ambient vibration recordings used to map glaciers thickness - A first study from alpine glaciers
No full textMicrotremor measurements and the Nakamura's HVSR (Horizontal to vertical spectral ratio) technique, generally used for site-effect studies as well as to determine the thickness of soft sediment layers, can be effectively applied to map the thickness of glaciers. In this work the GPR (ground penetrating radar) and multichannel seismic methods, widely employed to image the earth interior, are applied to validate the HVSR technique on some alpine glaciers: the Pian di Neve glacier on the Adamello massif (Italy), the Forni glacier in the Ortles/Cevedale massif (Italy) and the Aletsch glacier (Switzerland). Comparing the results obtained from the different methods we show that the resonance frequency in the HVSR spectra can be well correlated with the ice thickness at the site, in a wide range from tens of meters to more than 800 m. The application of the passive seismic method on glaciers, requiring less economic and operational efforts, enables to avoid most of the logistical difficulties affecting the GPR and active seismic methods in these extreme environments
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