Comment on ‘On sensitivity kernels for ‘wave-equation’ transmission tomography’ by de Hoop and van der Hilst



The finite-frequency sensitivity kernels developed by Dahlen et al. are an appropriate tool for inverting traveltimes of non-triplicated P, S, PP and SS waves, measured by cross-correlation with a synthetic pulse. The critique of this theoretical methodology in a recent paper by de Hoop & van der Hilst is based upon the incorrect notion that one can account for errors in the synthetic pulse and/or origin time of an earthquake by a modification of the Fréchet kernels expressing the first-order dependence upon the perturbation in the wavespeed.