Resolution limit of traveltime tomography

We derive an explicit formula relating a recovered 3-D seismic slowness image to the actual seismic slowness under the assumption that a tomographically complete collection of finite-frequency traveltime shifts is inverted using linearized ray theory. The tomographically recovered image is blunted, or diminished in amplitude, and blurred, or spread laterally, as a result of wave front healing and other finite-frequency diffraction effects. The 1-D spreading varies as the cube root of the amplitude reduction, so that total volume-integrated slowness is conserved.