The effect of a rough core-mantle boundary on PKKP

Abstract

Scattering by a slightly-rough core—mantle boundary (CMB) with small-scale radial variations of up to a few hundred metres, has been an attractive (though non-unique) interpretation of at least part of the precursors to PKLKP. Here it is shown that a slightly-rough CMB has an observable effect on PKKP as well, if the signal-to-noise ratio is sufficiently high. Both large- and small-scaletopography must be dynamically produced, if current estimates of the viscosity of the lower mantle (_~10²² Poise) are correct.