Toksöz, M. Nafi and Ben-Menahem, Ari (1963) Velocities of mantle Love and Rayleigh waves over multiple paths. Bulletin of the Seismological Society of America, 53 (4). pp. 741-764. ISSN 0037-1106. https://resolver.caltech.edu/CaltechAUTHORS:20140801-153223415
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Abstract
Phase velocities of Love waves from five major earthquakes are measured over six great circle paths in the period range of 50 to 400 seconds. For two of the great circle paths the phase velocities of Rayleigh waves are also obtained. The digitized seismograph traces are Fourier analyzed, and the phase spectra are used in determining the phase velocities. Where the great circle paths are close, the phase velocities over these paths are found to be in very good agreement with each other indicating that the measured velocities are accurate and reliable. Phase velocities of Love waves over paths that lie far from each other are different, and this difference is consistent and much greater than the experimental error. From this it is concluded that there are lateral variations in the structure of the earth's mantle. One interpretation of this variation is that the mantle under the continents is different from that under the oceans, since the path with the highest phase velocities is almost completely oceanic. This interpretation, however, is not unique and variations under the oceans and continents are also possible. Group velocities are computed from the phase velocities and are also directly measured from the seismograms. The group-velocity curve of Love waves has a plateau between periods of 100 and 300 seconds with a shallow minimum at about 290 seconds. The sources of error in both Fourier analysis and direct time domain methods of phase velocity measurement are discussed.
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Additional Information: | Copyright © 1963, by the Seismological Society of America. Manuscript received on February 6, 1963. The work was supported by Grant No. AF-AFOSR-25-63 of the Air Force Office of Scientific Research as part of the Advanced Research Projects Agency Project VELA-UNIFORM. The time series analysis and group velocity computer programs that were used in the analysis of the data were written by Mr. Shelton S. Alexander. Acknowledgment is also due to Dr. James Brune for clarifying certain aspects of his method. Mr. Laszlo Lenches is credited for technical aid in the preparation of this manuscript. | ||||||
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Issue or Number: | 4 | ||||||
Record Number: | CaltechAUTHORS:20140801-153223415 | ||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20140801-153223415 | ||||||
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ID Code: | 47845 | ||||||
Collection: | CaltechAUTHORS | ||||||
Deposited By: | George Porter | ||||||
Deposited On: | 01 Aug 2014 22:41 | ||||||
Last Modified: | 03 Oct 2019 06:57 |
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