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Surveys in Geophysics

, Volume 30, Issue 4–5, pp 355–376 | Cite as

Array Triplication Data Constraining Seismic Structure and Composition in the Mantle

  • Yi Wang
  • Lianxing Wen
  • Donald Weidner
Original Paper

Abstract

Seismic data recorded in the upper mantle triplication distance range between 10° and 30° are generated by wave propagation through complex upper mantle structure. They can be used to place constraints on seismic velocity structures in the upper mantle, key seismic features near the major discontinuities, and anisotropic structure varying with depth. In this paper, we review wave propagation of the upper mantle triplicated phases, how different key seismic features can be studied using upper mantle triplicated data, and the importance of those seismic features to the understanding of mantle temperature and composition. We present two examples of using array triplicated phases to constrain upper mantle velocity structures and detailed features of a certain discontinuity, with one for a shallow event and the other for deep events. For the shallow event, we present examples of how the array triplication data can be used to constrain several key properties of the upper mantle: existence of a lithospheric lid, existence of a low velocity zone beneath the lithospheric lid, and P/S velocity ratio as a function of depth. For deep events, we show examples of how array triplication data can be used to constrain the detailed structures of a certain discontinuity: velocity gradients above and below the discontinuity, velocity jumps across the discontinuity and depth extents of different velocity gradients. We discuss challenges of the upper mantle triplication study, its connection to other approaches, and its potential for further studying some other important features of the mantle: the existence of double 660-km discontinuities, existence of low-velocity channels near major discontinuities and anisotropy varying with depth.

Keywords

Triplication data Upper mantle Velocity structures Upper mantle discontinuity Mantle composition 

Notes

Acknowledgments

We thank the principal investigators of the Kaapvaal Seismic Array, the BANJO and BLSP for their efforts in collecting the data and the New Chinese Digital Seismic Network (NCDSN) for providing the data, and Sue Webb and Matthew Fouch for the digitized geological boundaries in Africa. This work is supported by an NSF grant #0439978.

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Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Department of GeosciencesState University of New York at Stony BrookStony BrookUSA

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