A map of topography on the 410-km discontinuity from PP precursors

Authors

  • Megan P. Flanagan,

    1. Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla
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  • Peter M. Shearer

    1. Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla
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Abstract

We derive a new map of global topography on the 410-km discontinuity from observations of precursors to PP obtained by stacking almost 25,000 long-period seismograms. The inferred ‘410’ topography exhibits average peak-to-peak amplitude of about 30 km, has a strong degree-one component, and is highly correlated with previous results obtained from SS precursors [Flanagan and Shearer, 1998]. Spatial variations in ‘410’ topography appear unrelated to ocean-continent differences, suggesting that continental roots are not a significant factor in observed global temperature variations at 410 km depth.

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