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Abstract.A multichannel analysis is introduced to constrain seismic anisotropy from the shear wave splitting of 5'K5' and SKKS.This technique utilizes simultaneously a set of records coming from different azimuths. The splitting intensity of 5'K5' waves, measured by the amplitude of the transverse component, depends on the angle between the back azimuth of the earthquake and the direction of the symmetry axis and on the delay time 5t between the two quasi-shear waves. It is shown that the splitting parameters can be determined from the azimuthal dependence of the splitting intensity, which is given by the first right eigenvector of the matrix containing the transverse components of all the records. Alternatively, the splitting intensity can be measured by projecting the transverse components on the radial components derivatives. Experiments on synthetic seismograms demonstrate that both approaches provide robust estimates of the splitting parameters. However, the projection approach gives measurements that are closer to the inputs and with smaller error bars, which suggests that it should be preferred when the signal-to-noise ratio is low.