The observation of inner core shear waves

Although the Earth's inner core has long been thought to be solid, there ha ve not, as yet, been unequivocal observations of inner core shear waves. He re we present observations of the phases pPKJKP and SKJKP for the Flores Se a event of 1996 June 17. The observations support the value of approximatel y 3.6 km s(-1) for the inner core shear wave velocity and open up new possi bilities for exploring the anisotropic structure and the attenuation proper ties of the inner core. The analysis and validation of the observation is b ased on a new method that can be used in the search for and identification of inner core shear waves. In this method normal mode synthetics for a soli d inner core are compared with those for a fluid inner core. It is only by such comparisons that it is possible to be certain that inner core shear wa ves, rather than interferences of other phases, are responsible for observe d energy maxima in stacked seismic records.