NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Anisotropy and shear-velocity heterogeneities in the upper mantleLong-period surface waves are used to map lateral heterogeneities of velocity and anisotropy in the upper mantle. The dispersion curves are expanded in spherical harmonics up to degree 6 and inverted to find the depth structure. The data are corrected for the effect of surface layers and both Love and Rayleigh waves are used. Shear wave velocity and shear polarization anisotropy can be resolved down to a depth of about 450 km. The shear wave velocity distribution to 200 km depth correlates with surface tectonics, except in a few anomalous regions. Below that depth the correlation vanishes. Cold subducted material shows up weakly at 350 km as fast S-wave anomalies. In the transition region a large scale pattern appears with fast mantle in the South-Atlantic. S-anisotropy at 200 km can resolve uprising or downwelling currents under some ridges and subduction zones. The Pacific shows a NW-SE fabric.
Document ID
19840042455
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Nataf, H.-C.
(California Inst. of Tech. Pasadena, CA, United States)
Nakanishi, I.
(California Inst. of Tech. Pasadena, CA, United States)
Anderson, D. L.
(California Institute of Technology Pasadena, CA, United States)
Date Acquired
August 12, 2013
Publication Date
February 1, 1984
Publication Information
Publication: Geophysical Research Letters
Volume: 11
ISSN: 0094-8276
Subject Category
Geophysics
Accession Number
84A25242
Funding Number(s)
CONTRACT_GRANT: NSG-7610
CONTRACT_GRANT: NSF EAR-81-15236
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available