1. A method of processing seismic data comprising the steps of: a) recording the amplitudes in first, second, and third directions of seismic energy received at a seismic receiver as a function of time, the first, second, and third directions not being co-planar; b) generating a time-dependent combined amplitude A(t) of the seismic data from the amplitudes in the first, second, and third directions using 4 A &af; ( t ) = &Sum; n = 1 3 &it; H A &af; ( d n &af; ( t ) ) ; and c) time-picking the seismic energy arrival time from the combined amplitude.