8,771 research outputs found
3-D Mapping of the Seismic Attenuation in the Upper Mantle
No full textL'objectif de cette thèse est de construire un modèle d'atténuation sismique du manteau supérieur dela Terre en utilisant un jeu de données original construit par Debayle et Ricard (2012). Ce jeu dedonnées est l'un des plus complet au monde (plus de 375 000 sismogrammes analysés pour extrairel'atténuation et la vitesse de phase du mode fondamental et des cinq premiers harmoniques des ondesde Rayleigh).Les mesures d'atténuation sont tout d'abord traitées pour extraire les effets de l'expansion géométriqueet de la focalisation, minimiser les effets d'erreurs sur la source, écarter les mesures incertaines etregrouper les mesures redondantes. Elles sont ensuite régionalisées pour obtenir des cartes desvariations latérales de l'atténuation des ondes de Rayleigh pour chaque mode et chaque période. Ladernière étape est l'inversion en profondeur des cartes. Elle permet d'obtenir QsADR17, un modèle 3Dde l'atténuation des ondes S dans le manteau supérieur.QsADR17 est corrélé avec la tectonique de surface jusqu'à 200 km de profondeur, avec une faibleatténuation sous les continents et une forte atténuation sous les océans. Des anomalies de forteatténuation sont observées jusqu'à 150~km de profondeur sous les rides océaniques, et persistent à plusgrande profondeur jusque dans la zone de transition sous la plupart des points chauds. La présence delarges anomalies atténuantes situées à 150 km de profondeur sous l'océan Pacifique suggère queplusieurs panaches thermiques viennent s'étaler dans l'asthénosphère. Nous avons également détecté laprésence d'hétérogénéités de composition à la base des cratons et dans un certain nombre de régionsactives.The aim of this study is to build a 3-D attenuation model of Earth's upper-mantle using a unique datasetbuilt by Debayle & Ricard (2012). This dataset is among the largest in the world: more than 375,000seismograms were analyzed to extract Rayleigh-wave attenuation and velocity measurements for thefondamental mode and the five first harmonics between 40 and 240 s periods.First, attenuation measurements are processed to extract the effects of geometrical attenuation and offocusing and defocusing, in order to minimize the influence of errors on the seismic source, to avoidpotentially incorrect data, and to cluster redondant measurements. Then, measurements are regionalizedto obtain Rayleigh-wave maps for each mode and each period. The last step is the inversion of thesemaps to obtain the depth dependent attenuation. Eventually, we obtain QsADR17, a 3-D model of Swaveattenuation in the upper mantle.QsADR17 is correlated with surface tectonics down to 200 km depth, with low attenuation under thecontinents and high attenuation under the oceans. High-attenuation anomalies are found under oceanicridges down to 150~km depth, and under most of the hotspots at larger depth down to the transitionzone. A large high-attenuation anomaly at 150~km depth under the Pacific ocean suggest that thermalplumes pound into the asthenosphere. We also detect compositional heterogeneities at the base of thecratons and in active areas
ROSENTHAL, Eric Inventory of documents
No full textCOVERAGE 1904; 1 File; 011 metre.Private papers of Eric Rosenthal, author, journalist and broadcaster
tritrophic-dispersal-model: Code used for creating figures for "Non-hierarchical dispersal promotes stability and resilience in a tri-trophic metacommunity"
No full text<p>This is the commented code used for creating figures for the paper. Any questions regarding the code should be directed to the corresponding author and repository owner (Eric Pedersen). </p>
Eric Velazquez Spanish Language Picture Book Award 2022 Acceptance Speech
No full textAuthor Eric Velazquez gives his Silver Medal acceptance speech for Pulpo Guisado (Holiday House)https://educate.bankstreet.edu/spanishlanguageaward/1001/thumbnail.jp
Eric C. Lincoln, Professor of Sociology and Religion, 1971
No full textThis is an interview with Eric C. Lincoln. Eric was a Professor of Sociology and religion, Union Theological Seminary and author of many books and articles on Negro history. In this recording the contributors discuss local memphis politics, sociology, and race relations compared to that of other cities in the South and the rest of the country
Interview with Eric Bentley, author, drama critic, and playwright
No full textDistinguished drama critic and Bertolt Brecht scholar, Eric Bentley is interviewed by WTMJ-TV host Jim Peck and John B. Fuegi, associate professor of Comparative Literature. Bentley recalls his association with Brecht, the critical and creative aspects of literature, and his interest in writing plays for the theater.GrayscaleSoun
Dr. Eric Yellin – Faculty Author Interview
No full textDr. Eric Yellin, Associate Professor of History and American Studies discusses his new book, Racism in the Nation’s Service: Government Workers and the Color Line in Woodrow Wilson’s America, published recently by the University of North Carolina Press. In this book, Dr. Yellin argues that President Wilson’s administration successfully segregated the federal government in the age of progressive politics. He investigates how the enactment of the segregation policy imposed a color line on American opportunity and implicated Washington in the economic limitation of African Americans for decades to com
A global shear velocity model of the upper mantle from fundamental and higher Rayleigh mode measurements
No full textInternational audienceWe present DR2012, a global SV-wave tomographic model of the upper mantle. We use an extension of the automated waveform inversion approach of Debayle (1999) which improves our mapping of the transition zone with extraction of fundamental and higher-mode information. The new approach is fully automated and has been successfully used to match approximately 375,000 Rayleigh waveforms. For each seismogram, we obtain a path average shear velocity and quality factor model, and a set of fundamental and higher-mode dispersion and attenuation curves. We incorporate the resulting set of path average shear velocity models into a tomographic inversion. In the uppermost 200 km of the mantle, SV wave heterogeneities correlate with surface tectonics. The high velocity signature of cratons is slightly shallower (approximate to 200 km) than in other seismic models. Thicker continental roots are not required by our data, but can be produced by imposing a priori a smoother model in the vertical direction. Regions deeper than 200 km show no velocity contrasts larger than +/- 1\% at large scale, except for high velocity slabs within the transition zone. Comparisons with other seismic models show that current surface wave datasets allow to build consistent models up to degrees 40 in the upper 200 km of the mantle. The agreement is poorer in the transition zone and confined to low harmonic degrees (<= 10)
Essentials of Dental Radiography and Radiology / Eric Whaites and Nicholas Drage.
No full textPrevious edition: Essentials of dental radiography and radiology / Eric Whaites. Fourth edition. Edinburgh ; New York : Churchill Livingstone, 2007.Includes bibliographical references (pages 461-464) and index.x, 478, [2] pages
10th C. Eric Lincoln Lecture Series, 1992
No full textPart of the 10th anniversary of the C. Eric Lincoln lecture series Dr. Love Henry Whelchel moderates a panel of scholars. The panel includes Dr. C. Eric Lincoln, Dr. Jacquelyn Grant, and Dr. John Hope Franklin. The panel discusses the life of George Washington Williams (author of History of the Negro Race in America). The discussion includes issues related to Womanist theology, Islamic religion, sociology, religion and history.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the National Endowment for Humanities - Humanities Collections and Reference Resources Implementation Project Grant in supporting the processing and digitization of a number of its major archival collections as part of the project: Spreading the Word: Expanding Access to African American Religious Archival Collections at the Atlanta University Center Robert W. Woodruff Library
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