1,721,050 research outputs found
Tecniche sismiche passive: indagini a stazione singola
No full textLe vibrazioni ambientali sono costituite da
onde che hanno attraversato porzioni significative
del sottosuolo, la struttura del segnale
registrato in superficie è potenzialmente in
grado di fornire informazioni sul mezzo attraversato
dalle onde. Completa e integra il
cap. 3.1.5 degli ICMS (2008)
Ambient noise measurements to support emergency seismic microzonation: the Abruzzo 2009 earthquake experience
No full textASSESSMENT OF SEISMIC SITE AMPLIFICATION AND OF SEISMIC BUILDING VULNERABILITY IN THE REPUBLIC OF MACEDONIA, CROATIA AND SLOVENIA
No full text
The attenuation of seismic intensity in Italy
No full textSeismic intensity is, by definition, an index for the classification of the severity of earthquake effects observed in a settlement. However the experience of many decades of its use within functional relations with other parametric quantities have shown that it represents a quite reliable estimator of ground motion amplitude and that it can be confidently related to instrumentally measured quantities by a logarithmic relation. Most intensity attenuation relations from the literature model empirically the difference between epicentral intensity I_0 (defined as the maximum observed intensity or something less that that) and the intensity at the site. This means assuming that I_0 is actually the average intensity observed at the epicenter and that it scales with site intensity with coefficient equal to 1. We analyzed the Italian macroseismic dataset that can be obtained by combining the two major Italian macroseismic databases following the choices made by the compilers of the parametric catalog of Italian earthquakes. It contains about 50,000 observations from ancient times to 1992. We considered an attenuation equation with log-linear dependence with hypocentral distance (depth fixed to 10 km) and an additional empirical term proportional to I_0 I_s=a + b D + c log{D} + d I_0 We found that: i) the intensity data observed at sites located at distance larger than the one at which the expected average intensity is below the limit of diffuse perceptibility (degree IV) are clearly incomplete and might bias the resulting attenuation relation, ii) intensity data with uncertain estimates (i.e. VI-VII) have frequencies lower of about 30-50% than regular ones and thus must be modeled separately, iii) the average intensity at the epicenter is on average from one to two degrees lower than I_0, iv) epicentral intensity contributes to the attenuation relation with a coefficient significantly different from 1.0 (about 0.7-08) thus indicating the it cannot be considered a reference ground-motion level but rather an estimator of the energy of the earthquake, v) the statistical distribution of intensity residuals closely resembles a normal one but with a significant skewness that can be appropriately modeled by a modified Azzalini distribution
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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