Three-dimensional sensitivity kernels for surface wave observables

We calculate three dimensional (3‐D) sensitivity kernels for fundamental‐mode surface wave observables based on the single‐scattering (Born) approximation. The sensitivity kernels for measured phases, amplitudes and arrival angles are formulated in the framework of surface wave mode summation. We derive kernels for cross‐spectral multitaper measurements; as a special case, the results are applicable to single‐taper measurements. Cross‐branch mode‐coupling effects are fully accounted for in the kernels; however, these effects can probably be ignored at the present level of spatial resolution in global phase‐delay tomography. The narrowly concentrated spectra of the windows and tapers commonly used in global surface wave studies enable the kernels to be computed extremely efficiently.