1,721,067 research outputs found
Slip distribution on a thrust fault at a plate boundary: the 2003 Chengkung earthquake, Taiwan
No full textRapid determination of moment magnitude from the near-field spectra: application to the april 6 2009, L'Aquila seismic sequence
No full textOn April 6th 2009, a magnitude Mw=6.1 earthquake struck the Abruzzi region in central Italy. Despite its moderate size, the earth- quake caused more than 300 fatalities and partially destroyed the city of L’Aquila and many villages in its surroundings. The main shock was preceded by an earthquake swarm that started at the end of 2008, and, by the end of November 2009, more than 16,000 aftershocks with M> 0.5 have been recorded by the INGV seismic network.
Current advances in data transmission and communication yield high quality broadband velocity and strong motion waveforms in near real-time. These data allow for the rapid characterization of earthquake sources in terms of fault geometry, focal depth and seismic moment. Delouis et al. (2009) have developed a methodology for rapid determination of moment magnitude from the near-fields spectra. In this study we test this methodology on the L’Aquila sequence earthquakes for which we have already com- puted the time domain moment tensor solutions (TDMT, Scognamiglio et al., 2010).UnpublishedMontpellier, FRANCE3.1. Fisica dei terremotiope
Rapid determination of moment magnitude from the near-field spectra: application to the april 6 2009, L'Aquila seismic sequence
No full textOn April 6th 2009, a magnitude Mw=6.1 earthquake struck the Abruzzi region in central Italy. Despite its moderate size, the earth- quake caused more than 300 fatalities and partially destroyed the city of L’Aquila and many villages in its surroundings. The main shock was preceded by an earthquake swarm that started at the end of 2008, and, by the end of November 2009, more than 16,000 aftershocks with M> 0.5 have been recorded by the INGV seismic network.
Current advances in data transmission and communication yield high quality broadband velocity and strong motion waveforms in near real-time. These data allow for the rapid characterization of earthquake sources in terms of fault geometry, focal depth and seismic moment. Delouis et al. (2009) have developed a methodology for rapid determination of moment magnitude from the near-fields spectra. In this study we test this methodology on the L’Aquila sequence earthquakes for which we have already com- puted the time domain moment tensor solutions (TDMT, Scognamiglio et al., 2010).UnpublishedMontpellier, FRANCE3.1. Fisica dei terremotiope
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
Relations between fault and earthquake properties
No full textJ’examine les relations entre propriétés des failles géologiques long-termes et propriétés des forts séismes que produisent ces failles. J’ai compilé les données sismologiques disponibles sur les grands séismes historiques mondiaux, et cartographié, sur images satellitaires, les failles long-termes rompues par ces séismes et les traces des ruptures. L’analyse combinée des données montre que : i) les failles long-termes ont certaines propriétés génériques (organisation des réseaux, segmentation latérale, forme de distribution du glissement cumulé, etc) ; ii) les forts séismes ont également des propriétés communes (similarité de distribution du glissement cosismique, du nombre de segments rompus, de la chute de contrainte sur chaque segment majeur rompu, de la distance relative entre hypocentre et zone de glissement maximum, etc) ; iii) la maturité structurale des failles est la propriété tectonique qui impacte le plus le comportement des forts séismes. Il est probable que cette maturité diminue la friction statique et la complexité géométrique du plan de faille. Elle agit sur la localisation de la zone d’initiation du séisme, sur la localisation et l’amplitude maximum du glissement cosismique, sur la direction de décroissance de ce glissement, sur la « capacité » de la rupture à se propager et donc sur sa vitesse de propagation. Elle dicte le nombre de segments majeurs qui peuvent être rompus, et par conséquent, elle contrôle la longueur totale et la chute de contrainte globale de la rupture. Pour comprendre la physique des forts séismes, il apparaît donc indispensable d’analyser conjointement les propriétés des failles rompues et les propriétés des séismes produits.I examine the relations between the properties of long-term geological faults and the properties of the large earthquakes these faults produce. I have gathered available seismological information on large historical earthquakes worldwide and mapped in detail, on satellite images, both the long-term fault and the rupture traces. The combined analysis of the data shows that: i) long-term faults have a number of generic properties (arrangement of overall fault networks, lateral segmentation of fault traces, form of cumulative slip distribution, etc); ii) large earthquakes also have generic properties (similarity of envelope shape of coseismic slip-length profiles, of decrease in rupture width along rupture length, of number of broken segments, of stress drop on broken segments, of relative distance between hypocenter and zone of maximum slip, etc); iii) the structural maturity of the faults is the tectonic property most impacting the behavior of large earthquakes. The maturity likely acts in reducing both the static friction and the geometric complexity of the fault plane. It partly governs the location of the earthquake initiation, the location and amplitude of the maximum coseismic slip, the direction of the coseismic slip decrease, the rupture propagation efficiency and speed, the number of major fault segments that are broken, and hence the rupture length and its overall stress drop. To understand the physics of earthquakes, it thus seems necessary to analyze jointly the tectonic properties of the broken faults and the seismological properties of the earthquakes
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