Crustal Electrical Structure of the Ganzi Fault on the Eastern Tibetan Plateau: Implications for the Role of Fluids in Earthquakes

Round 1

Reviewer 1 Report

Based on the inversion of three-dimensional magnetotelluric method, this paper obtains the conductivity characteristics of the crust at some Ganzi fault positions, analyzes the specific reasons for the low conductivity in the inversion results, and analyzes the possible causes of inducing earthquakes. The data are more detailed and reliable. It is suggested to publish after major modification. The following suggestions are made:

1.The main point of the paper in is that the inducement of the earthquake under the Ganzi fault may be due to the transfer of the lower crustal fluid to the brittle crust, and the overpressure fluid pressure in the brittle crust is increasing. It is suggested that this part of the abstract (Line24-27) directly expresses this meaning, rather than mentioning the stress accumulation caused by plate collision, which is not the focus of the paper.

2.Since the paper refers to the three-dimensional inversion method, Figure 6 shows the horizontal sections at different depths, and Figure 7 shows two vertical sections, it is suggested to add a three-dimensional figure to combine Figure 6, Figure 7 and Figure 9 to make it easier to understand and better express the views of the article.

3.It is suggested to adjust and refine some complex language expressions in the paper. Some sentences are too difficult and complex, and there may be some grammatical errors, such as Line 308-311.

4.The paper analyzed the causes of C2 and C3 in Line 256-288, but did not analyze the causes of C1. It is suggested to make supplementary explanations.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Using the fluid research method, this manuscript studies the crustal electrical structure of Ganzi fault in the east of Qinghai Tibet Plateau. It is considered that the reason of intraplate seismic activity is the migration of fluid to the crust with poor permeability, or the local stress concentration near the structural boundary. There are two key problems: (1) it seems that the work of this study deviates from the theme of the journal; (2) There is no scientific discussion part in this manuscript. Although one chapter is result and discussion, the content is definite the result. It is suggested that the authors should add a separate discussion section, analyze and compare the results of this study with those of predecessors from the aspects of data, methods and results, and analyze the progressiveness and limitations of this work. In addition, it is also necessary to prospect the future work.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The paper entitled “Crustal Electrical Structure of the Ganzi Fault on the Eastern Tibetan Plateau: Implications for the Role of Fluids in Earthquakes” is of an interesting topic. The topic of the paper falls within the scopes of the journal “Remote Sensing”.

The authors attempted to investigate if seismicity at the broader area of the Ganzi Fault on the Eastern Tibetan Plateau originates from fluid migration to the less permeable crust or from local stress concentrations near the tectonic boundary. For this purpose they imaged the electrical structure of the crust beneath the Ganzi fault using a three dimensional magnetotelluric inversion technique, which is host to an assemblage of resistive and conductive features extending into the lower crust.

The conclusions of the paper are based on the findings after the application of the methodology. I am not a native speaker but the manuscript in my opinion reds quite well.

I think that the manuscript suffers in its structure. The authors should extend the “Introduction” section providing a literature review on the methodology they applied. At the end of the “Introduction” they should clearly present the aims of their paper and the research questions. The introduction in its present form seems to be a part of the “study area” section.

Another issue is that they need to separate the methodology from the results. The methodology should describe all the steps they followed to reach the results. A flow diagram including these methodological steps should be appreciated by the readers of the final version of the paper.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The paper has been revised in detail according to the first comments, and it is suggested to publish.

1. Figure 7 and Figure 9 did not indicate their positions like other pictures in the paper. It is recommended to mark at appropriate positions and add the description of 3D image at line 258

Author Response

The paper has been revised in detail according to the first comments, and it is suggested to publish. 1. Figure 7 and Figure 9 did not indicate their positions like other pictures in the paper. It is recommended to mark at appropriate positions and add the description of 3D image at line 258

Reply: Thank you very much for your positive feedback and the critical comments. We have taken all these comments into account, and have major corrections in this revised manuscript. According to you suggestion, we have added the positions of Figure 7 and Figure 9 in the revised manuscript, Lines 230 and 266 in blue. We have added the description of 3D image at line 258-260 in blue. “Figure 9. The 3D model displayed with the 10 Ωm isosurface. The yellow isosurface represents the isosurface of 10 Ωm. This model reveals three conductors in the crust (C1–C3). MT sites  indicated as black triangles. High conductors C2 and C3 connect to the lower crust.”

Author Response File: Author Response.docx

Reviewer 2 Report

It seems that the work of this study deviates from the theme of the journal.

Author Response

It seems that the work of this study deviates from the theme of the journal.

Reply: We have imaged the electrical structure of the crust beneath the Ganzi fault using a three-dimensional magnetotelluric inversion technique in this manuscript. Broadly speaking, geophysics also belongs to a category of remote sensing, which uses special sensors to collect remotely sensed data in order to help researchers "sense" things about the Earth (surface or subsurface). So, the topic of the paper falls within the scopes of the journal “Remote Sensing”.

Author Response File: Author Response.docx