Evaluation of the Experimental Design and The Estimation of Parameters by Deep Crustal Electromagnetic Sounding Systems.

摘要

The objective of this report is to quantitatively examine the problem determining parameters of a resistive layer in the earth's crust by electrical sounding methods. The advantages and disadvantages of a quantitive assessment of the resolution of model parameters is briefly examined. Particular electrical sounding methods considered here are; (1) magnetotelluric and audio magnetotelluric methods (MT-AMT); (2) direct current (DC) Schlumberger (VES) method; and (3) DC dipole-dipole sounding methods with a finite source and receiver. These methods constitute, in principle, the majority of electrical methods which have been used to determine electrical parameters of the earth's crust. An important class of electrical sounding methods, the artificial or controlled source electromagnetic induction methods, is not considered. First described are general aspects of qualitative and quantitative methods to estimate the resolving power of a given set of crustal sounding measurements. Resolving power is the capability of the measurements to determine the bounds of a set of earth model parameters. For the crustal sounding problem, the model parameters are the resistivities and the layer thicknesses of a horizontally stratified earth. Finally the resolving power of a particular set of sounding measurements is described.