Improving Finite Element Optimization of InSAR-Derived Deformation Source Using Integrated Multiscale Approach

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Document attached

Comments for author File: Comments.pdf

Author Response

Thank you very much for your valuable comments. We have provided point-by-point responses to the review comments, please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The objective of this paper is to improve finite element optimization of InSAR-derived deformation source using integrated multiscale approach. In particular, the role of multiscale methods and boundary analysis techniques is investigated, combined with optimization/inversion procedures, for deriving a more reliable model of the physical and geometric parameters of volcanic deformation sources. The above are implemented for the Campi Flegrei caldera (CFc) case study.  

This paper is both engaging and well-organized, with all essential sections - including the Introduction, Materials and Methods, Results, Discussion, and Conclusions - appropriately addressed. The “Materials and Methods” and “Results” sections are further enhanced by clear sub-sections that offer additional detail. Additionally, all Figures, Tables, and Diagrams align well with the analysis presented in the manuscript. However, certain revisions are recommended to enhance the overall quality of the paper. In particular:

General comments

• Please, expand structural complexity. For example, incorporation of fault geometries and layered rheologies to reduce residuals in key areas could be applied.
• Regarding dynamic modeling, describe the time-dependent pressure changes to align with CFc’s episodic uplift history, please.
• To validate the results and strengthen interpretation, a comparison with independent GPS datasets should be performed. Please, apply.

Specific comments

• Lines 37-43: Although the contribution of geodetic modelling in the displacement study (related to faults planes and volcanic plumbing) is highlighted, there is no mention related to the geodetic strain estimation. This should be added in this paragraph. Typical papers, in which the corresponding information can be obtained and optionally be cited, are the following: https://doi.org/10.1016/j.jseaes.2024.106376, 2. https://doi.org/10.3390/rs14092112.
• Lines 58-65: This paper focuses on single-source modeling. The multi-source or time-dependent scenarios mentioned at this part, are beyond the current framework. Please, remove or modify this part.
• Lines 210-214: While elastic parameter variations are included, effects of multiphase fluids or viscoelastic rheology are not addressed. Please, modify.
• Line 469: The “Conclusions” section should be modified, as it resembles an abstract rather than conclusions. This section should include the major findings of the paper (numbering the concluding remarks could be implemented). Please, apply.

Author Response

Thank you very much for your valuable comments. We have provided point-by-point responses to the review comments, please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript "Manuscript ID remotesensing-3778069" entitled "Improving Finite Element Optimization of InSAR-derived deformation source using integrated multiscale approach" has been submitted to Remote Sensing. The authors use an integrated multiscale approach for constraining the geometric parameters of volcanic deformation sources and then perform a Monte Carlo optimization of FE parametric modeling. This approach allows for contemplating more physically complex scenarios, retrieving more robust solutions, and significantly decreasing computing time. First, they apply the Multiridge, ScalFun methods and Total Horizontal Derivative (THD) technique to determine the position and horizontal sizes of the deformation source. We then perform two independent cycles of parametric FE optimization by keeping (I) all the parameters unconstrained and (II) constraining the geometric parameters of the over-pressured source. The results show that (II) yields statistically more reliable solutions than (I), resulting in an extraordinary tenfold reduction in computing time. There are major deficiencies, and it is recommended for the major review:

1. This is an excellent abstract. It successfully outlines the problem, the proposed solution, the methodology, the application, the key findings, and the significance of the research.

• In abstract, Inclusion of specific quantitative findings would provide a clearer picture of the results. End with a strong remark that reinforces the importance of study and its contributions to the field.
• The first sentence is broad and could be more precise. Consider making it more specific to the research contribution. Academic tone is typically more measured.

2. The introduction is thorough and convincingly explains the importance of integrated multiscale approach for the assessment of InSAR-derived deformation. However, there are still a few areas that could be enhanced to ensure completeness and clarity: Clearly identifying the research gap and explicitly stating the objectives of your study in the introduction are crucial for setting up the reader’s expectations and highlighting your study’s contribution.
3. Figure 1 should be the study area which provides clearer context about study area. It’s very confusing for readers to understand.
4. The discussion provided is detailed and comprehensive, but it can be improved by enhancing the discussion section with comparisons to prior work, a candid evaluation of limitations, and clear future research directions can significantly strengthen the scientific rigor and impact of your study.
5. The conclusions provided summarize the main findings and their implications well but can be enhanced by including a few additional elements to provide a more comprehensive closure to the study.

• Conclusion section is very long, make it more precise and easier for readers.
• Emphasize the most significant results and their implications more clearly.
• The last sentence is solid but could be more impactful with a clear forward-looking or policy-relevant takeaway.

6. Further, on numerous occasions I had trouble with the language and I also found the repetition of sentences. A careful reading of the paper is mandatory to remove typos and to soften the language hardships. So, it is my opinion that the paper should undergo major revision for a better explanation and for a complete revision of the language.

Check all references to ensure the literature review is up to date.

Author Response

Thank you very much for your valuable comments. We have provided point-by-point responses to the review comments, please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The authors proposes a method that uses an integrated multiscale approach to improve the optimization problem of finite element inversion for volcanic deformation sources. The research content demonstrates a certain degree of innovation; however, there are still some issues that need to be revised:

(1)Is this method only applicable to the inversion problem of volcanic source parameters, or is it equally applicable to other optimization problems of InSAR-derived deformation sources, such as the inversion problem of seismic fault parameters?

（2）When using the finite element method to address the optimization problem of InSAR-derived deformation sources, the first concern for most researchers is the operational efficiency of this method. However, the author does not provide a detailed comparative analysis in the paper. First, compared with the analytical method, what is the performance of the method proposed by the author in terms of computational efficiency and computational accuracy? Meanwhile, the author needs to specify: to what extent of difference between the two methods can we adopt the method proposed by the author, and to what extent of difference can we simply use the analytical method instead?

（3）The authors lacks a comparison with existing finite element methods. Currently, a number of studies have been published on addressing the optimization problem of InSAR-derived deformation sources using finite element methods. It is necessary for the author to provide quantitative analysis on the following aspects: what differences exist between these existing methods and the one proposed by the author, and whether the author’s proposed method can solve the problems that these existing methods fail to address.

(4) The authors calculated the posterior probability density functions of the parameters in the paper. This is a time-consuming computation process; however, the author did not provide relevant information about this aspect in the paper. It is suggested that the author add content related to this part.

(5) It is suggested that the authors add simulation examples to verify the proposed method when conducting the validation of the method.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Thank you very much for your valuable comments. We have provided point-by-point responses to the review comments, please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The suggested changes to the text were partially adopted and the text was improved in its structure and citations. From this second evaluation, I consider that the article has the quality to be published.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have answered all the questions I raised.