26,198 research outputs found
Author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Distribution of noise sources for seismic interferometry
No full textWe demonstrate that the distribution of seismic noise sources affects the accuracy of Green's function estimates and therefore isotropic and anisotropic tomographic inversions for both velocity and attenuation. We compare three methods for estimating seismic noise source distributions and quantify the potential error in phase velocity, azimuthal anisotropy and attenuation estimates due to inhomogenous source distributions. The methods include: (1) least-squares inversion of beamformer output, (2) a least-squares inversion of year long stacked noise correlation functions assuming both a 2-D plane wave source density model and (3) a 3-D plane wave source density model.We use vertical component data from the 190 stations of the Southern California Seismic Network and some US Array stations for 2008. The good agreement between the three models suggests the 2-D plane wave model, with the fewest number of unknown parameters, is generally sufficient to describe the noise density function for tomographic inversions. At higher frequencies, 3-D and beamforming models are required to resolve peaks in energy associated with body waves.We illustrate and assess isotropic and azimuthally anisotropic phase velocity and attenuation uncertainties for the noise source distribution in southern California by inverting isotropic lossless synthetic Fourier transformed noise correlation function predictions from modelled 2-D source distribution. We find that the variation in phase velocity with azimuth from inhomogeneous source distribution yields up to 1 per cent apparent peak-to-peak anisotropy. We predict apparent attenuation coefficients from our lossless synthetics on the same order of magnitude as those previously reported for the region from ambient noise. Since noise source distributions are likely inhomogeneous varying regionally and with time, we recommend that noise correlation studies reporting attenuation and anisotropy incorporate source density information
Multichannel array diagnosis using noise cross-correlation
No full text© 2008 Acoustical Society of AmericaA practical application of noise cross-correlation for the diagnosis of a multichannel ocean hydrophone array is derived. Acoustic data were recorded on a horizontal line array on the New Jersey Shelf while Tropical Storm Ernesto passed through. Results obtained from active source measurements reveal that signals from several hydrophones, which were recorded on certain channels before the storm, are recorded on different channels after the storm. Noise cross-correlation of data recorded during the storm show when, and in what manner, these changes took place.Laura A. Brooks, Peter Gerstoft and David P. Knoble
Global P, PP, and PKP wave microseisms observed from distant storms
No full textMicroseisms are the continuous background vibrations of the Earth observed between earthquakes. Most microseism studies have focused on low frequency energy (0.05–0.5 Hz) propagating as surface waves, but in the microseism spectrum there is also energy that propagates as body waves (P-waves). Using array analysis on southern California stations we show that these body waves are generated in the ocean from distant storms and propagate deep within the Earth's mantle and core as P, PP and PKP phases. Comparisons with ocean wave hindcast data identify several distinct source regions in both the northern and southern hemispheres. Analyses of these body waves demonstrate that microseisms often have a strong P-wave component originating from distant locations. <br/
Moral Good, the Beatific Vision, and God’s Kingdom Writings by Germain Grisez and Peter Ryan, S.J.. Edited by Peter J. Weigel
No full textFor close to half a century, the work of Germain Grisez has been highly influential, and his writings continue to receive considerable attention from philosophers and theologians of diverse viewpoints. His co-author for this work is the professor and noted moral theologian Fr. Peter Ryan, S.J., currently the executive director of the Secretariat of Doctrine and Canonical Affairs of the United States Conference of Catholic Bishops (USCCB). These two eminent scholars explore fundamental questions about Christian eschatology, moral theory, the purpose of human life, and the promise of human fulfilment. The authors examine Christian teaching on the final destiny of persons, investigating the meaning of God's kingdom, the hope of the beatific vision, and the centrality of moral goodness and divine grace in one's final end. This work is an ideal source for students, scholars, ministers and lay persons interested in basic questions of Christian theology, the philosophy of religion, ethical theory, and Catholic doctrin
Murder on the mountain: author talk with Peter J. Wosh
No full textAuthor talk by Peter J. Wosh on May 5th, 2022, on his book, "Murder on the Mountain: crime, passion, and punishment in gilded age New Jersey.
Lunchtime Talk with Author and Attorney Peter Godwin
No full textAuthor and attorney Peter Godwin gave a lunchtime talk about the topics discussed in his book, The Fear, which focuses on the human rights situation in Zimbabwe under the rule of Robert Mugabe
Shallow-water seismoacoustic noise generated by tropical storms Ernesto and Florence
No full textLand-based seismic observations of double frequency (DF) microseisms generated during tropical storms Ernesto and Florence are dominated by signals in the 0.15-0.5 Hz band. In contrast, data from sea floor hydrophones in shallow water (70 m depth, 130 km off the New Jersey coast) show dominant signals in the ocean gravity-wave frequency band, 0.02-0.18 Hz, and low amplitudes from 0.18 to 0.3 Hz, suggesting significant opposing wave components necessary for DF microseism generation were negligible at the site. Florence produced large waves over deep water while Ernesto only generated waves in coastal regions, yet both storms produced similar spectra. This suggests near-coastal shallow water as the dominant region for observed microseism generation.James Traer, Peter Gerstoft, Peter D. Bromirski, William S. Hodgkiss, and Laura A. Brook
An essay about the Francis Paudras Collection on Bud Powell by Peter Pullman
No full textThis is an essay about the Francis Paudras Collection on Bud Powell written by Peter Pullman, a jazz scholar and author of Wail: The Life of Bud Powell (Brooklyn: Bop Changes, 2012).One image file (pdf)This project was supported by a Recordings at Risk grant from the Council on Library and Information Resources (CLIR). The grant program is made possible by funding from The Andrew W. Mellon Foundation
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