Comment on "The existence of an inner core super-rotation questioned by teleseismic doublets" by Georges Poupinet, Annie Souriau, and Olivier Coutant

Poupinet et al. [J. Geophys. Res. 89 (1984) 5719] presented a new methodology for testing whether the PKP travel times observed at College, Alaska station from South Sandwich Islands earthquakes indicate inner core rotation. They applied the method to seven events and concluded that there is no evidence for PKP(DF) times increasing systematically with event dates, and therefore no reason to postulate that the inner core rotates at a different rate than the mantle. In a reanalysis of the same seven events, I find that their results are systematically biased by the choice of radial Earth models and by incorrectly assuming that one of the phases had reversed polarity. I also question their choice of events, but upon correcting for these biases, conclude that these seven events are consistent with the previous model of inner core rotation.