Travel times in point-to-arc geometry obtained using different methods. Top: the panels show measured travel times using a Gabor fit (left) and a GB04 fit (middle), as well as travel times from the Born kernels (right). Both measured and forward travel times were averaged over a set of distances and latitudes. Bottom: forward travel times obtained using different sets of kernels, using the unmatched power spectrum and not averaging over distance and latitude (left, Born kernels), using the matched power spectrum and not averaging over distance and latitude (middle, Born kernels), and travel times obtained from ray kernels (right) averaged in the same way as the travel times displayed in the top row.