Magnetotelluric Regularized Inversion Based on the Multiplier Method

Round 1

Reviewer 1 Report

Dear Editor,

I believe this work can be published in present form.

regards,

Reviewer

Author Response

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Reviewer 2 Report

The conventional MT inversion involves a large number of the calculations in penalty term and has difficulties selecting exact regularization factors. Authors propose a multiplier-based MT inversion scheme, which is implemented by introducing the incremental Lagrangian function. Two models are used to verify the performance of the multiplier method in the regularized MT inversion. However,it is necessary to supplement the inversion results of the actual field observational data.

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Reviewer 3 Report

The manuscript is devoted to the inversion of MT data, which is very important for mineral exploration. However, the approaches proposed in the manuscript do not appear to be new.

 

The Lagrange multiplier method has previously been applied to 2D inversion of magnetotelluric data, for example in De Groot-Hedlin, C., & Constable, S. (2004). Inversion of magnetotelluric data for 2D structure with sharp resistivity contrasts. GEOPHYSICS, 69(1), 78–86. doi:10.1190/1.1649377

 

What is the novelty and difference from this paper?

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Reviewer 4 Report

In magnetotelluric studies, the solution of the inverse problem plays a key role. The development of new methods for efficient minimization of the functional, providing an increase in the reliability of the solution and reducing computational time, is an urgent task. Therefore, the paper will be useful to specialists, but requires some refinement.

 

1. The authors use the regularization term (stabilizer) R(m), but do not explain what form they use in their calculations. This term can be specified in different forms, respectively, providing smoothing, focusing, or proximity to the a priori model.

2. The authors do not indicate which magnetotelluric data they are inverting. Are these the apparent resistivities and the phases of the longitudinal and transverse impedances? Tippers are not used?

3. It is indicated that the authors use the finite element method to solve the direct problem. Is this their own algorithm, is it published? Fig. 2 shows the topography, was it taken into account?

4. Figures 1, 2 and 6 do not show the axes and color scale titles. In Figure 1, it is not signed what the lines of different colors mean, and it is not very convenient to look for explanations in the text.

5. The text of the paper is not sufficiently verified, there are repetitions, for example, the whole phrase is repeated in lines 234 and 235.

6. English is not my native language, but the problems of using it are striking. For example, the authors use the term resistance, while it describes the integral characteristic of an object (for example, a wire) and is measured in Ohms. And the property of the medium is measured in Ohms per meter and is called resistivity.

 

The general impression is that the authors paid insufficient attention to the preparation of the text. In addition to the abovementioned remarks, there are several more places in the paper that are excessively verbose, or, conversely, where you have to think and guess. It will be good if the authors work a little more on the text to make it clearer and more understandable. After that, the paper can be published.

Author Response

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