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Integrated deterministic and probabilistic strong ground motion prediction: application to 1980 Irpinia earthquake, M=6.9, Southern Italy
No full textBuilding damage scenarios based on exploitation of Housner intensity derived from finite faults ground motion simulations
No full textIn this paper earthquake damage scenarios for residential buildings (about 4200 units) in Potenza (Southern Italy) have been estimated adopting a novel probabilistic approach that involves complex source models, site effects, building vulnerability assessment and damage estimation through Damage Probability Matrices. Several causative faults of single seismic events, with magnitude up to 7, are known to be close to the town. A seismic hazard approach based on finite faults ground motion simulation techniques has been used to identify the sources producing the maximum expected ground motion at Potenza and to generate a set of ground motion time histories to be adopted for building damage scenarios. Additionally, site effects, evaluated in a previouswork through amplification factors of Housner intensity, have been combined with the bedrock values provided by hazard assessment. Furthermore, a new relationship between Housner and EMS-98 macroseismic intensity has been developed. This relationship has been used to convert the probability mass functions of Housner intensity obtained from synthetic seismograms amplified by the site effects coefficients into probability mass function of EMS-98 intensity. Finally, the Damage Probability Matrices have been applied to estimate the damage levels of the residential buildings located in the urban area of Potenza. The proposed methodology returns the full probabilistic distribution of expected damage, thus avoiding average damage index or uncertainties expressed in term of dispersion indexes
High-Frequency Directivity in Strong Ground Motion Modeling Methods
No full textWe are investigating two distinct strong ground motion simulation techniques as regards
their high-frequency directivity: i) the composite model with a fractal subevent size dis-
tribution, based on the method of summation of empirical Green’s functions, and ii) the
integral model with the k-squared slip model with k-dependent rise time, based on the
representation theorem. We test the simulations in a 1D layered crustal model against em-
pirical PGA attenuation relations, particularly with regard to their uncertainty, described
by the standard deviation ( ). We assume that any synthetic model for a particular earth-
quake should not provide a PGA scatter larger than the observed scatter for a large set
of earthquakes. The 1999 Athens earthquake (Mw=5.9) is studied as a test example. In
the composite method, the synthetic data display a scatter of less than ±2 around the
empirical mean. The k-squared method displays a larger scatter, demonstrating strong
high-frequency directivity. It is shown that the latter can be reduced by introducing a
formal spectral modification.
1 Introduction
Low-frequency directivity effects are well known. For example, there is a number of seismic
recordings of recent earthquakes (e.g., 1992 Landers, 1994 Northridge, 1995 Kobe, 1999
Chi-Chi), which show long-period velocity pulses caused by rupture propagation towards
a station. This effect can be successfully explained by the apparent source time function
varying with azimuth (Haskell, 1964).
2Unpublishedope
High-Frequency Directivity in Strong Ground Motion Modeling Methods
No full textWe are investigating two distinct strong ground motion simulation techniques as regards
their high-frequency directivity: i) the composite model with a fractal subevent size dis-
tribution, based on the method of summation of empirical Green’s functions, and ii) the
integral model with the k-squared slip model with k-dependent rise time, based on the
representation theorem. We test the simulations in a 1D layered crustal model against em-
pirical PGA attenuation relations, particularly with regard to their uncertainty, described
by the standard deviation ( ). We assume that any synthetic model for a particular earth-
quake should not provide a PGA scatter larger than the observed scatter for a large set
of earthquakes. The 1999 Athens earthquake (Mw=5.9) is studied as a test example. In
the composite method, the synthetic data display a scatter of less than ±2 around the
empirical mean. The k-squared method displays a larger scatter, demonstrating strong
high-frequency directivity. It is shown that the latter can be reduced by introducing a
formal spectral modification.
1 Introduction
Low-frequency directivity effects are well known. For example, there is a number of seismic
recordings of recent earthquakes (e.g., 1992 Landers, 1994 Northridge, 1995 Kobe, 1999
Chi-Chi), which show long-period velocity pulses caused by rupture propagation towards
a station. This effect can be successfully explained by the apparent source time function
varying with azimuth (Haskell, 1964).
2Unpublishedope
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
Variations on the Author
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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