Monopole sources do not allow the measurement of shear slowness in slow formations, that is, formations having shear slownesses greater than the fluid slowness. Dipole sources allow the measurement of shear slowness in slow formations by means of the flexural'mode [4]; however, the flexural mode is dispersive and contradicts the assumptions of STC. Fortunately, an analog of STC suitable for processing dispersive waves can be defined. The dispersive analog of STC backpropagates waveforms according to model dispersion curves parameterized by the formation shear slowness S and computes semblance. Figure 1: Flexural mode dispersion curve f) (solid Backpropagation is performed in the frequency domain. The value of S that maximizes semblance is line) and excitation (dashed line) in a fast, S taken as the estimate of formation shear slowness.