PREFERENTIAL CONTINUATION FOR POTENTIAL-FIELD ANOMALY ENHANCEMENT

A new class of filter transfer function derived from Wiener filter and Green's equivalent layer principles is presented for upward and downward-continuation enhancement of potential-field data. The newly developed transfer function is called the preferential continuation operator. In contrast to the conventional continuation operator, the preferential continuation operator possesses a continuation response that acts preferentially upon a specific band of the observed potential field's Fourier amplitude spectrum. The transfer function response approaches the response of an all-pass filter away from this band. This response characteristic is useful for at least two common potential-field signal enhancement applications. First, it is possible with preferential upward continuation to attenuate shallow-source, short-wavelength, potential-field signals while minimally attenuating deep-source, long wavelength signals (as often happens after application of conventional upward continuation). Second, it is possible with preferential downward continuation to enhance deep-source, long wavelength signals without overamplifying shallow-source, short-wavelength signals (as often happens after application of conventional downward continuation). Preferential continuation, used qualitatively for anomaly enhancement, ably overcomes these two Limitations of conventional continuation enhancement.