We demonstrate the use of a new, t − x domain, pattern-based signal/noise separation technique to separate ground roll from primary reflection events. Ground roll is notoriously difficult to model with generality, but the technique requires a kinematically correct model of the noise. We obtain an imperfect model of the ground roll directly from the data itself, by application of a suitable lowpass filter. On a 2-D receiver line gather taken from a 3-D shot gather, in which the ground roll is spatially aliased and has nonlinear moveout, the separation results improve markedly over direct subtraction of the noise model from the data.