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Construction of Synthetics for 2D structures; core phases

Helmberger, Don V. and Zhao, Lian-She and Garnero, Edward J. (1996) Construction of Synthetics for 2D structures; core phases. In: Seismic modelling of earth structure. Editrice compositori , Bologna, Italy, pp. 183-221. ISBN 978-8877940803.

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Recent studies have emphasized the prominence of anomalous high and low velocity regions in the lower mantle. For example, slower than average seismic shear wave velocities beneath the central Pacific accompanied by surrounding higher than average velocities is common to most tomographic studies (e.g., see Tanimoto, 1990; Masters et al., 1992; Su and Dziewonski, 1994). Images from these reports indicate long wavelength (> 3000 km) structures with velocity anomalies of up to ± 2.5%. A particularly prominent slow region occurs just north of the Fiji-Tonga region in all of these models and has been noted by many authors with respect to differential times of body waves, such as ScS-S by Sipkin and Jordan (1980), S-SKS by Garnero and Helmberger (1993) and others. The latter study demonstrates that S-SKS time predictions made from present 3D models do not agree with all of the observations. Since this anomaly may well be associated with up-welling currents in the mantle, the seismic details become particularly important especially at the shorter wavelengths associated with body waves (5-100 km). Thus, better methods of generating realistic synthetics for these types of complex models would be useful and are addressed in this study.

Item Type:Book Section
Additional Information:© 1996 Editrice compositori. We would like to thank Xiaoming Ding for his help in generating a number of these figures. This research was supported by the National Science Foundation, grant EAR93-16441, and by the Air Force Office of Scientific Research under grant F49620-92-10221. Contribution 5340, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, 91125.
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Air Force Office of Scientific Research (AFOSR)F49620-92-10221
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Caltech Division of Geological and Planetary Sciences5340
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ID Code:35758
Deposited By: Tony Diaz
Deposited On:07 Feb 2013 19:56
Last Modified:03 Oct 2019 04:31

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