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AGU: Geophysical Research Letters

 

Keywords

  • plume
  • LLSVP
  • multi-pathing

Index Terms

  • Seismology: Mantle
  • Seismology: Body waves
  • Tectonophysics: Earth's interior: composition and state
  • Geodesy and Gravity: Earth's interior: dynamics

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L09302, 5 PP., 2010
doi:10.1029/2009GL042339

A narrow, mid-mantle plume below southern Africa

Daoyuan Sun

Seismological Laboratory, California Institute of Technology, Pasadena, California, USA

Don Helmberger

Seismological Laboratory, California Institute of Technology, Pasadena, California, USA

Michael Gurnis

Seismological Laboratory, California Institute of Technology, Pasadena, California, USA

New waveform tomographic evidence displays a narrow plume-like feature emitting from the top of the large African low-velocity structure in the lower mantle. A detailed SKS wavefield is assembled for a segment along the structure's southern edge by combining multiple events recorded by a seismic array in the Kaapvaal region of southern Africa. With a new processing technique that emphases multi-pathing, we locate a relatively jagged, sloping wall 1000 km high with low velocities near it's basal edge. Forward modeling indicates that the plume's diameter is less than 150 km and consistent with an iso-chemical, low-viscosity plume conduit.

Received 29 December 2009; accepted 29 March 2010; published 4 May 2010.

Citation: Sun, D., D. Helmberger, and M. Gurnis (2010), A narrow, mid-mantle plume below southern Africa, Geophys. Res. Lett., 37, L09302, doi:10.1029/2009GL042339.

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