Detection of a D" discontinuity in the south Atlantic using PKKP

Sebastian Rost, Justin Revenaugh

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


A strong arrival in the early coda of major-arc PKKPab is observed on recordings of earthquakes in the Banda Sea region from the short-period, small-aperture Yellowknife array. The arrival has a move-out close to PKKPab with an average delay of ∼12 s. We show that the phase is most likely an underside reflection from a D discontinuity above the PKKP reflection point at the core-mantle boundary beneath the southern Atlantic on the edge of the African superplume. Differential travel times between PKKPab and PKdKP (the underside reflection at the D discontinuity) is used to constrain potential D velocity models. The high amplitude of PKdKP requires proximity to the b-caustic adding further velocity control. We find that a P-velocity model with a sharp positive velocity jump e1280 km above the core-mantle boundary, and a negative velocity gradient closer to the core-mantle boundary, fits the data well.

Original languageEnglish (US)
Pages (from-to)4-1 - 4-4
JournalGeophysical Research Letters
Issue number16
StatePublished - Aug 15 2003


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