ESTIMATION OF MARINE SOURCE SIGNATURES FROM DIRECT ARRIVALS TO HYDROPHONE GROUPS*

Deterministic deconvolution of seismic data recorded with a non‐minimum phase source, such as a sparker, requires an estimate of the source signature. Present methods of deterministic signature estimation and deconvolution require additional field equipment (near‐ or far‐field hydrophones), or else make a deterministic estimate of the effective source signature (the free‐field source signature convolved with source and receiver ghosts). By analyzing the direct arrival signal to normal hydrophone groups it is shown that extraction of the free‐field source signature from this signal is possible for a spherically symmetric source, and it is demonstrated that the use of this signature for a preliminary deterministic deconvolution gives better results on sparker data than minimum‐phase whitening deconvolution applied on its own. The applicability of the method to non‐spherically symmetric sources, such as arrays, is also discussed.

This paper is published with the permission of the Director, Bureau of Mineral Resources, Geology and Geophysics, Canberra, Australia.