Dahlen, F. A.F. A.DahlenHung, Shu-HueiShu-HueiHungNolet, GuustGuustNolet2019-07-022019-07-022000-01-010956540Xhttps://scholars.lib.ntu.edu.tw/handle/123456789/412269We use body wave ray theory in conjunction with the Born approximation to compute 3-D Fréchet kernels for finite-frequency seismic traveltimes, measured by cross-correlation of a broad-band waveform with a spherical earth synthetic seismogram. Destructive interference among adjacent frequencies in the broad-band pulse renders a cross-correlation traveltime measurement sensitive only to the wave speed in a hollow banana-shaped region surrounding the unperturbed geometrical ray. The Fréchet kernel expressing this sensitivity is expressed as a double sum over all forwardpropagating body waves from the source and backward-propagating body waves from the receiver to every single scatterer in the vicinity of this central ray. The kernel for a differential traveltime, measured by cross-correlation of two phases at the same receiver, is simply the difference of the respective single-phase kernels. In the paraxial approximation, an absolute or differential traveltime kernel can be computed extremely economically by implementing a single kinematic and dynamic ray trace along each source-to-receiver ray. © 2000 RAS.Body waves | Fréchet derivatives | Global seismology | Ray theory | Tomography, traveltimejournal article10.1046/j.1365-246X.2000.00070.x2-s2.0-0034010082https://api.elsevier.com/content/abstract/scopus_id/0034010082