Rayleigh Wave Phase Velocities in the Atlantic Ocean
The phase velocities of Rayleigh waves are found for many paths in the north Atlantic. The single station technique is used with earthquakes in the Mid-Atlantic Ridge. The major contributor to the error in phase velocity is the uncertainty in epicentral location and origin time. Focal depth and mech...
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Oxford University Press
1974
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fthighwire:oai:open-archive.highwire.org:gji:36/1/105 2023-05-15T17:34:05+02:00 Rayleigh Wave Phase Velocities in the Atlantic Ocean Weidner, Donald J. 1974-01-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/36/1/105 https://doi.org/10.1111/j.1365-246X.1974.tb03628.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/36/1/105 http://dx.doi.org/10.1111/j.1365-246X.1974.tb03628.x Copyright (C) 1974, Oxford University Press Articles TEXT 1974 fthighwire https://doi.org/10.1111/j.1365-246X.1974.tb03628.x 2013-05-28T06:08:55Z The phase velocities of Rayleigh waves are found for many paths in the north Atlantic. The single station technique is used with earthquakes in the Mid-Atlantic Ridge. The major contributor to the error in phase velocity is the uncertainty in epicentral location and origin time. Focal depth and mechanism are sufficiently well controlled for these events that they do not significantly add to the phase velocity error. The resulting uncertainty is ± 0.02 km s−1 for the period range 20-100 s. The ocean is regionalized into ridge and basin. Both ray theory and Rytov's method are used to extract the dispersion characteristics of each region from the observations. Large lateral variations of the basin dispersion suggest a further subdivision. These variations can be explained entirely by variations in sediment thickness. The deduced upper mantle model of the ocean basin is characterized by a shear velocity reversal at 40 km depth with a lid shear velocity of 4.7 km s−1. The lowest shear velocities are centered at a depth of 125 km. The lid shear velocity can be reduced to 4.6 km s−1 only if both the thickness of the lid increases and the density increases. Phase velocities for the Mid-Atlantic Ridge imply that the upper mantle shear velocity under the ridge is significantly lower than that under the ocean basin at depths greater than 20 km. Text North Atlantic HighWire Press (Stanford University) Mid-Atlantic Ridge Geophysical Journal International 36 1 105 139 |
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HighWire Press (Stanford University) |
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English |
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Articles |
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Articles Weidner, Donald J. Rayleigh Wave Phase Velocities in the Atlantic Ocean |
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Articles |
description |
The phase velocities of Rayleigh waves are found for many paths in the north Atlantic. The single station technique is used with earthquakes in the Mid-Atlantic Ridge. The major contributor to the error in phase velocity is the uncertainty in epicentral location and origin time. Focal depth and mechanism are sufficiently well controlled for these events that they do not significantly add to the phase velocity error. The resulting uncertainty is ± 0.02 km s−1 for the period range 20-100 s. The ocean is regionalized into ridge and basin. Both ray theory and Rytov's method are used to extract the dispersion characteristics of each region from the observations. Large lateral variations of the basin dispersion suggest a further subdivision. These variations can be explained entirely by variations in sediment thickness. The deduced upper mantle model of the ocean basin is characterized by a shear velocity reversal at 40 km depth with a lid shear velocity of 4.7 km s−1. The lowest shear velocities are centered at a depth of 125 km. The lid shear velocity can be reduced to 4.6 km s−1 only if both the thickness of the lid increases and the density increases. Phase velocities for the Mid-Atlantic Ridge imply that the upper mantle shear velocity under the ridge is significantly lower than that under the ocean basin at depths greater than 20 km. |
format |
Text |
author |
Weidner, Donald J. |
author_facet |
Weidner, Donald J. |
author_sort |
Weidner, Donald J. |
title |
Rayleigh Wave Phase Velocities in the Atlantic Ocean |
title_short |
Rayleigh Wave Phase Velocities in the Atlantic Ocean |
title_full |
Rayleigh Wave Phase Velocities in the Atlantic Ocean |
title_fullStr |
Rayleigh Wave Phase Velocities in the Atlantic Ocean |
title_full_unstemmed |
Rayleigh Wave Phase Velocities in the Atlantic Ocean |
title_sort |
rayleigh wave phase velocities in the atlantic ocean |
publisher |
Oxford University Press |
publishDate |
1974 |
url |
http://gji.oxfordjournals.org/cgi/content/short/36/1/105 https://doi.org/10.1111/j.1365-246X.1974.tb03628.x |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/36/1/105 http://dx.doi.org/10.1111/j.1365-246X.1974.tb03628.x |
op_rights |
Copyright (C) 1974, Oxford University Press |
op_doi |
https://doi.org/10.1111/j.1365-246X.1974.tb03628.x |
container_title |
Geophysical Journal International |
container_volume |
36 |
container_issue |
1 |
container_start_page |
105 |
op_container_end_page |
139 |
_version_ |
1766132801379237888 |