Observations of precursors to P'P' from a recent exceptionally large d
eep earthquake in the Fiji Islands (moment magnitude = 7.6) ai an arra
y of broadband stations in California revealed mid-mantle reflectors n
ear depths of 785 kilometers and 1200 kilometers under the southern Af
rican rift, Such observations, previously reported primarily in subduc
tion zones, suggest that these reflectors may have a global character.
Our analysis, which also indicated a sharp, uplifted 670-kilometer di
scontinuity, demonstrates the power of sparse regional broadband array
s for the study of weak, frequency-dependent features in deep-Earth st
ructure.