Strong seismic scatterers near the core-mantle boundary north of the Pacific Anomaly

Xiaolong Ma, Xinlei Sun, Douglas A. Wiens, Lianxing Wen, Andrew Nyblade, Sridhar Anandakrishnan, Rick Aster, Audrey Huerta, Terry Wilson

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Tomographic images have shown that there are clear high-velocity heterogeneities to the north of the Pacific Anomaly near the core-mantle boundary (CMB), but the detailed structure and origin of these heterogeneities are poorly known. In this study, we analyze PKP precursors from earthquakes in the Aleutian Islands and Kamchatka Peninsula recorded by seismic arrays in Antarctica, and find that these heterogeneities extend ~400 km above the CMB and are distributed between 30° and 45°N in latitude. The scatterers show the largest P-wave velocity perturbation of 1.0-1.2% in the center (160-180°E) and ~0.5% to the west and east (140-160°E, 180-200°E). ScS-differential travel-time residuals reveal similar features. We suggest that these seismic scatterers are the remnants of ancient subducted slab material. The lateral variations may be caused either by different slabs, or by variations in slab composition resulting from their segregation process.

Original languageEnglish (US)
Pages (from-to)21-30
Number of pages10
JournalPhysics of the Earth and Planetary Interiors
StatePublished - Apr 1 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science


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