Reassessment of a reported S-delay under Trindade

A correction to a paper by Okal and Anderson (1975) about multiple ScS travel-time anomalies is presented. Data for ScS2 surface bounces in the South Atlantic Ocean have been reanalyzed. From these data an ScS2-S residual of 23.6 seconds was found by Okal and Anderson (1975). This corresponded to an ScS2 surface bounce point under Trindade island and was inferred to be due to very slow upper mantle associated with the Trindade hot spot. The analysis presented here invalidates this conclusion. The nature of the upper mantle under Trindade is an open issue.