A method includes conditioning a set of multicomponent seismic data and
sensor orientation data, the multicomponent seismic data including
pressure data and particle motion data, acquired in a towed array, marine
seismic survey; digital group forming the conditioned pressure data, a
vertical particle motion component of the conditioned particle motion
data, and the conditioned sensor orientation data; and summing the
digitally group formed pressure data and the digitally group formed
vertical particle motion component.