Depth to BasementAnalytic SignalAnalytic Signal is an automated function that enables you to determine Analytic Signal depth solutions from gravity and magnetic profiles. The Analytic Signal function is based on the U.S.G.S. program PDEPTH (Phillips, 1997), which is based on the Nabighian method published by Misac Nabighian. (1972, 1974).
The Analytic Signal technique first calculates the analytic signal of the input profile using a Hilbert Transform. Local peaks in the Analytic Signal profile are interpreted as corners of source bodies and the shape of the peak contains information about the depth to the corner. In the absence of high-frequency noise and aliasing in the data, horizontal locations from Analytic Signal are highly accurate. For noisy input profiles, the results can be improved significantly by filtering the input anomaly and gradient data. The Analytic Signal GX uses a FFT technique to calculate the horizontal derivative if the user does not specify an input gradient channel. Analytic Signal is a GX function included in the Depth to Basement software extension for Oasis montaj. |
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The
input profiles are interpolated to an even sample interval using the
standard Oasis spline method before processing by the Analytic Signal GX.
The sample interval is the total profile length divided by the number of
points in the profile. Therefore, profiles with large gaps should be split
into multiple lines. 