Estimation of effective source signatures from marine VSP data

The authors present a simple method for estimating an effective source wavelet from the first arrival in marine vertical seismic profiling (VSP) data. The method, which utilizes the free-space Green`s function of the Helmholz equation, is simple and very computer efficient. They show examples from synthetic and real offset and walkaway VSP data. In the synthetic examples, they show that data modeled with the estimated wavelet give small residuals when subtracted from the reference data. In the real data examples, they show that when modeling with the wavelet estimated from the real data, in a smooth macromodel, they obtain a good fit between the first arrivals in the real and modeled data.