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Relative amplitudes of P and S waves as a mantle reconnaissance tool

McGinley, John R., Jr. and Anderson, Don L. (1969) Relative amplitudes of P and S waves as a mantle reconnaissance tool. Bulletin of the Seismological Society of America, 59 (3). pp. 1189-1200. ISSN 0037-1106.

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The unified magnitude, the ratio of the amiplitudes of S to P waves, and travel-time residuals were compiled from published data for the five Seismological Observatories, TFO, UBO, BMO, WMO and CBO. Using one of the stations as a reference, a relative measure of the above quantities was calculated for each of the other stations for each of a number of earthquakes. The stations in the Basin and Range Province are consistent with a markedly higher attentuation of P waves and a high attenuation of S relative to P when compared to the other stations. This latter observation indicates a high Poisson's ratio in the mantle under the Basin and Range. The delay times to these stations are also consistent with the high Poisson's ratio and with a low-velocity upper mantle. The ratio of the amplitudes of long-period S waves to short-period P waves varies by a factor of 4 among these stations. BMO, in eastern Oregon, has a high S/P amplitude ratio compared to other stations and a travel-time residual that is comparable to the observatories in the mid-continent. This may be another example of a seismic “window” into the upper mantle that is generated by underthrusting of the oceanic lithosphere.

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Additional Information:© 1969 Seismological Society of America. Manuscript received September 26, 1968. This research was supported by the Air Force Office of Scientific Research, United States Air Force, under AFOSR contract AF-49(638)-1337. We are grateful to David Hill for critically reading the manuscript.
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Air Force Office of Scientific Research (AFOSR)AF-49(638)-1337
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Caltech Division of Geological Sciences1574
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Official Citation: John R. McGinley, Jr. and Don L. Anderson Relative amplitudes of P and S waves as a mantle reconnaissance tool Bulletin of the Seismological Society of America June 1969 59:1189-1200
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45334
Deposited By: Ruth Sustaita
Deposited On:30 Apr 2014 15:28
Last Modified:03 Oct 2019 06:29

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