The Times of sP and sPKP
Harold Jeffreys · Geophysical Journal International · 1942
By an oversight these two phases were omitted from the calculation of travel-times by Bullen and myself."The calculation presents no special complications.In the following tables I give first the interval between P and sP, then the depth allowance, which is the difference between the times of sP for the actual depth and for a surface focus; the latter is the same as that of P for a surface focus.It varies much less with distance for a given focal depth and is therefore easier to interpolate.Since the effect of depth on PKP has already been given in the form of depth allowances I give that on sPKP also in this form alone.The interval sLDKP-PKP will then be obtained by adding the allowances without regard to sign.The column for 15 km.refers to a focus at the base of the upper layer, for h/R=o-oo to one at the base of the intermediate layer as usual.