| Abstract: | The interpretation of magnetic anomalies on the basis of model bodies is preferably done by making use of “trial and error” methods. These manual methods are tedious and time consuming but they can be transferred to the computer by making the required adjustments by way of the method of least squares. The general principles of the method are described. Essential presumptions are the following: - 1 the assumption of definite model bodies
- 2 the existence of approximation values of the unknown quantities (position, dip, magnetization, etc.)
- 3 a sufficiently large number of measuring values, so that the process of adjustment can be carried out.
The advantages of the method are the following: - 1 substantial automatization and a quick procedure by using computers
- 2 determination of the errors of the unknown quantities.
The method was applied to the interpretation of two-dimensional ΔZ- and ΔT-anomalies. Three types of model bodies are taken as basis of the computer program, viz. the thin dyke, infinite resp. finite in its extension downward and the circular cylinder. Only the measuring values are given to the computer. The interpretation proceeds in the following steps: - 1 calculation of approximation values
- 2 determination of the model body of best fit
- 3 iteration in the case of the model body of best fit.
The computer produces the end values of the unknown quantities, their mean errors, and the pertaining theoretical anomalies. These end results are given to a plotting machine, which draws the measured curve, the theoretical curve and the model bodies. Interpretation examples are given. |
