Isaiah Adelere

Ladoke Akintola University of Technology.

Dear Isaiah:

1) First of all the methods, try the RAPS estimation (FFT2RSPC GX) to calculate radially averaged power spectrum of an FFT2 Transform image. Also, you should be very careful with the grids Coordinate System.

You need to try to check the coordinate system of your input data to the RAPS estimation: if your current channels are latitude and longitude in degrees, you should create a new coordinate channels with X and Y in meters. This is because Oasis use of flat-coordinates (X and Y in meters, not geographic coordinates in degrees). Therefore, the outputs will also be in flat-coordinates, meters or wave numbers, expressed in 1 / km as indicated in the spectrum (Wavenumber (1 / K unit)). But, if you use geographic coordinates in degrees, all the results will be in degrees and the wave number follows it: will be in 1 / K_degrees, which makes no sense.

The RAPS method will give you an idea of ​​two or three average source-planar-depth of interfaces in your work area. Contemplate also Sir, that the RAPS answer will give you three averages values over the spectral window. Look out the RAPS has a lot of its power from the grid tapering outside your grid, so it's influenced your final values.

2) After the RAPS you have a preliminary idea about the depths of the sources of the anomalies: shallows, middles and deeper ones. Therefore, when you use another way, e.g., SPI (Thurston and Smith, 1997) you will have a depth value cutoff level, and any solutions deeper than this cutoff level will be rejected.

Also, you can use Standard Euler Deconvolution ED menu option (E3DECON GX) to apply Euler depth deconvolution as a tool for potential field interpretation.

You must check some items, such as Structural Index SI, maximum depth tolerance (all depth solutions with smaller than this tolerance will be accepted from the RAPS estimation), and the square-window-size (from the RAPS grid-cell-size). Efficacy of Euler Deconvolution is the best when the examination window is sufficient in magnitude to cover the whole anomaly, but not so large that it includes multiple anomalies. As a result of the disparity in the sizes of the anomaly, may you need to run ED two or three times with window-sizes each time a little or more different.

3) I recommend to visit two RG questions and answers by excellents colleagues:

a) How can I compare Radially Average Power Spectrum and 3D Euler Deconvolution applied to airborne magnetic data in Geosoft Oasis Montaj?

by Marco Antonio Couto Jr.

b) Radial power spectrum in MAGMAP, Geosoft Oasis Montaj Help?

by Jitendra Vaish.

I am available in case of any other questions you may have.

Mario E. Sigismondi

اؤيد اجابه قام Mario Emilio Sigismondi

I agree with the detailed answer provided by Mario Emilio Sigismondi