Surface Deformation Monitoring and Risk Mapping in the Surroundings of the Solotvyno Salt Mine (Ukraine) between 1992 and 2021

Round 1

Reviewer 1 Report

Title: Surface deformation monitoring and risk mapping in the surroundings of the Solotvyno Salt Mine between 1992 and 2021.

• The paper presents a study on displacement velocity field in rock-salt mining town Solotvyno based on InSAR time series analysis of ERS, Envisat and Sentinel-1 datasers, covering the time period between 1992 and 2021.
• The technical content of the paper is quite weak and it doesn't give a sufficient contribution.
• A lot of work has been published in this topic.
• The paper is not suitable for the publication on Sustainability.

Author Response

Dear Reviewer 1.

Thank You for your evaluation! I think that our paper is a good demonstration of an integrated, three different satellite data based, long term monitoring that provides significant information on the spatial and temporal trends of surface distortion and subsidence due to undermining to support sustainable strategic planning. We believe, that the long term coverage and integrated use of different historical satellite data, the  classification system and the way of presenting and interpreting  the results (Figures 16-23) are novel elements of this kind of studies. We tried to improve the paper and made several corrections and additions to be more clear and coherent. I hope You will value these additions.

Best regards

Endre Dobos

Reviewer 2 Report

In general, this paper presents good research. However, it is not well planned and structured. So, many corrections need to clarify. I want the authors to address the following points to improve the manuscript.

Please include the country information in the title and summary. Please include the country information in the title and abstract.

In the abstract part, the project titled "An international project (HUSKROUA/1702/6.1/0072 Revital I.)" is directly mentioned. This situation is not very suitable for the article, and you can give this information at the end of the article's introduction section. In the abstract, only include general statements such as what you find the article's purpose. So, The abstract of the article is inadequate. Therefore, an abstract should be written to better reflect the work from start to finish.

A design from general to specific should be made on the map of the study area given in Figure 1. Another map must be added to show its location in the country

Line 70-101: The general information about InSAR given in this section is at the top and examples of InSAR at the bottom will provide a better flow.

Line 102: the aim of the study should be at the end of the introduction.

A general to specific flow is expected from the entire introduction. and there should be links between paragraphs. please check the introduction part in general.

please summarize the project information between lines 127-140. This detailed information is not the subject of this article.

A title called "study area" can be added and information about the study site and the study site map can be added there.

I recommend using ALOS PALSAR DEM with a resolution of 12.5 m instead of the slope you gave in Figure 3. this data is totally free data and will provide a better visual.  You use it later in your analysis. Due to its resolution, it will better eliminate topographical effects.

Different terms are used, such as surface deformation, subsidence and displacements. If a single term is used on this subject, it will be more understandable for the article.

It should be added what kind of way was followed and which software was used when combining the data in ascending and descending direction.

Coordinate details should be added to the maps in the article.

I could not understand the sudden shift to "4th Stability Report of Sighetu Marmatiei". This was not mentioned in the introduction part of the study, in the abstract and aim parts.

If there will be a "Sighetu Marmatiei" section, you have to revise the article from the beginning.

figure 21 does not have a map feature.

There is no discussion section in the article. The results of the study should be compared with the findings of the relevant studies published in last three years to support the contributions and novelties of the study.

I always saw the velocity values in the LOS direction in the article. Vertical values not obtained using ASC and DSC data?

Author Response

Dear Reviwer 2.

 

Please find my responses below your comments

 

Comments and Suggestions for Authors

In general, this paper presents good research. However, it is not well planned and structured. So, many corrections need to clarify. I want the authors to address the following points to improve the manuscript.

THANK YOU FOR YOUR POSITIVE EVALUATION! WE TRIED TO FOLLOW YOUR SUGGESTIONS TO IMPROVE THE MANUSCRIPT.

Please include the country information in the title and summary. Please include the country information in the title and abstract.

IT HAS BEEN DONE!

In the abstract part, the project titled "An international project (HUSKROUA/1702/6.1/0072 Revital I.)" is directly mentioned. This situation is not very suitable for the article, and you can give this information at the end of the article's introduction section. In the abstract, only include general statements such as what you find the article's purpose. So, The abstract of the article is inadequate. Therefore, an abstract should be written to better reflect the work from start to finish.

THE ABSTRACT WAS REWRITTEN AND ALL PROJECT RELATED INFORMATION WAS REMOVED.

A design from general to specific should be made on the map of the study area given in Figure 1. Another map must be added to show its location in the country

IT HAS BEEN DONE

Line 70-101: The general information about InSAR given in this section is at the top and examples of InSAR at the bottom will provide a better flow.

DONE

Line 102: the aim of the study should be at the end of the introduction.

TRANSLOCATED, RESTRUCTURED

A general to specific flow is expected from the entire introduction. and there should be links between paragraphs. please check the introduction part in general.

WE DID SO! WE TRIED TO INTRODUCE A LOGICAL LINE OF PROBLEM TO SOLUTION.

please summarize the project information between lines 127-140. This detailed information is not the subject of this article.

DONE

A title called "study area" can be added and information about the study site and the study site map can be added there.

DONE

I recommend using ALOS PALSAR DEM with a resolution of 12.5 m instead of the slope you gave in Figure 3. this data is totally free data and will provide a better visual.  You use it later in your analysis. Due to its resolution, it will better eliminate topographical effects.

CHECKED THE WEBSITE, BUT NO DEM PRODUCT IS AVAILABLE FOR THE STUDY AREA. WE USED THE 25 METER EU-DEM INSTEAD. HOWEVER, I FOUND THE SITE VERY USEFUL FOR LATER PROJECT DATA SUPPORT

Different terms are used, such as surface deformation, subsidence and displacements. If a single term is used on this subject, it will be more understandable for the article.

WE BELIEVE THAT THESE TERM HAS SOME SLIGHT DIFFERENCE IN THEIR MEANING, WHICH WE WANTED TO KEEP TO BETTER CHARACTERIZE THE PROCESSES.

It should be added what kind of way was followed and which software was used when combining the data in ascending and descending direction.

Thank you for your suggestions. We have added the following lines to the end of the "2.2.1 Interferometric preprocessing" chapter (Starts from line 206): We also added the citation of the referred techniques.

 

“Both ascending and descending LOS data are the composites of 3D (east-west, north-south and vertical) displacements (Fialko and Simons 2001), which can be expressed as the following (in case of right looking SAR antenna such as S1):

 

,where α is the azimuth of the satellite, θ is the incidence angle at the selected surface point,  D_U is the displacement in vertical direction, D_E is the displacement in east-west direction; and D_N is the displacement toward the north. However, calculating the later one (D_N) component is cumbersome since at least three radar geometries would be necessary and it is not provided by the orbital system of S1. On the contrary, the azimuth angles of S1 are very close to the south-north direction, hence, the system is less sensitive to the displacements toward the north and the south, and the D_N  component can be neglected (Ng et al. 2011). A system of two equations can be used to describe the relationship of ascending (D_{LOS ASC}) and descending (D_{LOS DESC}) LOS measures of a given pixel, where of course, the east-west and vertical displacement components are the same.

 

 

The D_E and D_U displacement componentss have been calculated using the "Meta Combination" module  of Envi SARscape 5.6 in case of SBAS results. While, the "Shape Combination" module of the same software was evaluated on PS data for the decomposition (Fialko and Simons 2001, Ng et al. 2011).

As a second aspect of the decomposition of the LOS measurement, it should be noted that the spatial coverage of the ERS and Envisat measurements provided poor overlap of the ascending and descending geometries. Therefore, the decomposition of east-west and vertical components could led to massive data loss considering these sensors.”

 

#References:

Fialko Y., Simons M., 2001. The complete (3-D) surface displacement in the epicentral area of the 1999 Mw 7.1 Hector Mine earthquake, California, from space geodetic observations. Geophysical Research Letters, vol. 28, no 16, pp 3063-3066.

 

Ng, Alex Hay-Man, et al. "Deformation mapping in three dimensions for underground mining using InSAR–Southern highland coalfield in New South Wales, Australia." International Journal of Remote Sensing 32.22 (2011): 7227-7256.

 

Coordinate details should be added to the maps in the article.

DONE

I could not understand the sudden shift to "4th Stability Report of Sighetu Marmatiei". This was not mentioned in the introduction part of the study, in the abstract and aim parts.

REMOVED! IT WAS PART OF THE ORIGINAL STUDY, BUT THE PROGRESS AND RESULTS WERE NOT READY TO BE INTEGRATED INTO THE PAPER.

If there will be a "Sighetu Marmatiei" section, you have to revise the article from the beginning.

REMOVED! IT WAS PART OF THE ORIGINAL STUDY, BUT THE PROGRESS AND RESULTS WERE NOT READY TO BE INTEGRATED INTO THE PAPER.

figure 21 does not have a map feature.

REMOVED! IT WAS PART OF THE ORIGINAL STUDY, BUT THE PROGRESS AND RESULTS WERE NOT READY TO BE INTEGRATED INTO THE PAPER.

There is no discussion section in the article. The results of the study should be compared with the findings of the relevant studies published in last three years to support the contributions and novelties of the study.

HAS BEEN ADDED

I always saw the velocity values in the LOS direction in the article. Vertical values not obtained using ASC and DSC data?

Thank for your question. The east-west and vertical components of displacements have been decomposed in a way mentioned above. However, due to the poor overlap of ascending and descending geometry result of ERS and Envisat sensors, only LOS data have been kept for further analysis to prevent data loss induced by the combination of geometries. Therefore, the inter-sensor combination of displacements focuses on LOS data to provide temporal continuity. It should be noted that the displacements have a very strong vertical component and a minor, usually negligible east-west component, hence LOS data clearly reflect real displacement tendencies.

Therefore the previous chapter (2.3.1) continues this way:

 

“To prevent data loss induced by the combination of geometries, only LOS data have been kept for further analysis considering all the three sensors. Hence, the inter-sensor combination of displacements focuses on LOS data to provide temporal continuity. It should be noted that the displacements have a very strong vertical component and a minor, usually negligible east-west component, hence LOS data clearly reflect real displacement tendencies.”

 

S1 decomposed data have been kept for visualization purposed to demonstrate the strong vertical component of displacements. The following text have been added to chapter “3.1 Interferometric results (annual velocity of the site according to sensors)” starting from line 330:

 

“While analyzing the S1-based vertical displacements of the site, we see the same trends described just above (Figure 10). It become obvious soon that the main displacement component are observable along the vertical axis using both interferometric stacking techniques.”

 

Figure 10: S1-based vertical displacements of PS scatterers at the study site.

 

 

 

IN GENERAL, THANKS FOR THE CONSTRUCTIVE SUGGESTIONS AND POSITIVE, HELPFUL APPROACH

 

BEST REGARDS

ENDRE DOBOS

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

·        - Study seems to have improved considerably compared to the old version.

·         -I reiterate that a lot of work has been published on this topic but I cannot deny that long term monitoring applications are very laborious and demanding work.

·        - I hope that the stability and stability grid methodology can be a pioneer for other studies.

·       -  Additionally, please show the LOS displacement axis between -50, +50 values in the graphs in Figures 17-18 and 19. I understand that you want to make all graphics the same value, but it doesn't seem appropriate in terms of format.

Reviewer 2 Report

There is a high level of improvement in the revised manuscript. I would like to thank you for answering most of my requests. Hence, I recommend the manuscript for publication.