Landslide Detection Based on Multi-Direction Phase Gradient Stacking, with Application to Zhouqu, China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors address an important topic: the importance of listing landslides and monitoring their deformation useful for preventing landslide disasters. In detail, some landslides are difficult to detect due to low consistency caused by land use characteristics, vegetation cover in mountainous areas, and the difficulty of phase unwrapping caused by large landslide deformation. In this paper, a method is proposed to avoid the problem of inability to detect a part of the landslide due to phase rejection error.
Despite the interest in the topic, I believe some changes to the paper are needed before it can be considered ready for publication. Authors will find my suggestions listed in the attached file.
Comments for author File: 
Comments.pdf
Author Response
Please refer to the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors
The marked draft has comments, which will help you to improve the quality of the paper.
Comments for author File: Comments.pdf
Monor English corrections are required
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThis paper addresses an important issue of landslide monitoring in regions with low coherence and large deformation, where unwrapping errors may occur. The authors proposed and tested an approach based on multi-direction phase gradient stacking and used Sentinel-1 satellite ascending and descending data to detect landslides in Zhouqu County, China. They then compared their findings with the classical SBAS method.
The English writing is good, but some editing and proofreading are required. I believe this study fits very well within the scope of the journal. While the paper provides a clear image of the research performed and has sound experimental work, my main concerns are the significance of its contributions, even given the large effort that went into this study, and the validation of the results. Here are my major and minor comments
Major comments:
· Make sure to clearly emphasize the problem statement and research gap in the literature review
· The literature review could be significantly improved by including more recent papers on the same subject. The average of references goes back to nine years ago.
· As a reviewer, I would appreciate more information on the new methodological aspects of your study.
· The manuscript does not clearly state its limitations, despite the strength of the proposed methods.
· The manuscript must be checked for punctuation, errors in grammar, spelling, and formatting (Font changes, …).
· Authors claimed that their proposed approach reduced the data processing time. This should be further described.
Minor comments:
· The abstract should provide a brief summary of the study’s quantitative findings in numerical format
· The texts in Figure 1 are blurred and unreadable, while Figure 4 is not legible, making it impossible to validate.
· Line 50: [1616, 17] must be corrected.
· Abbreviations must be defined in their first appearances (i.e. DEM, …).
Comments on the Quality of English Language
The English writing is good, but some minor editing and proofreading are required.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThis study focuses on landslide detection in China. I find the topic interesting, thus, some parts need improvement. I want the authors to address the points enumerated below to improve the manuscript.
1. Keywords: I suggest changing the keywords that appear twice (in keywords and the title). This change will improve the visibility of the paper in bibliographic repositories, once a greater variety of words it will be used.
2. Lines 27-29: Sentence should be rephrased. The differences between conditioning and triggering factors must be clear.
3. The authors used the term “landslides” in the introduction. In English, this term refers to all types of landslides (e.g. shallow landslide, debris flow, rock falls…). In your analysis did you identify all these types of processes? If not, I suggest changing it to the correct process name.
4. Line 50: Duplicate citation.
5. The resolution of all figures needs to be improved. It was not possible to evaluate most of them.
6. Section 2: Please add the software used for the analysis.
7. Section 3.1: Please include the rainfall amounts and give more information about previous landslide events in the study area. Add one figure of a landslide in the study area.
8. Section 3.2: Include the resolution of the images used.
9. What is the average size of the landslides in your study area? Is the DEM with a 30 m resolution suitable for the analysis?
10. Line 246: …Ascending and Descending: (a)…
11. Section 4: Give more information about landslide characteristics (e.g. mean size, morphology, geology…) and make a comparison.
12. I suggest including a new figure with the location of the landslides mentioned in the discussion section. For example, the authors mentioned the Suoertou landslide, but we as readers do not know the exact location of this landslide in the study area.
13. Line 364: Include the area in km².
14. Discussion needs to be improved. Please add studies that applied the same or similar methods in China or worldwide.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 5 Report
Comments and Suggestions for AuthorsDear authors,
I have carefully read your manuscript, "Landslide detection based on multi-direction phase gradient stacking, with application to Zhouqu, China." The topic is interesting really interesting, and the findings seem to be sound. Nevertheless, before its acceptance, some minor issues should be solved.
Write out the full term followed by the abbreviation in brackets the first time you mention it in a document (SAR, DEM).
Revise the blank spaces throughout the manuscript.
In the introducing, authors should include that Helping in the flash flood susceptibility mapping is another major use of the SAR imagery (https://doi.org/10.1016/j.wace.2023.100595, https://doi.org/10.1016/j.jhydrol.2020.125682).
Producing some more tables with the results should be advisable.
L50: Revise the reference 1616.
Figures have to be redone since they are nearly unreadable.
Tables 2 and 3 present some words written in an incorrect format.
Kind regards
Comments on the Quality of English Language
Correct the article usage. Some examples: Landslide is a common geological disaster (Line 10 and L27); ...that part of landslide... (L18); ,... resulting in spectral differences between landslide area... (L35)
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 4 Report
Comments and Suggestions for AuthorsThe authors followed most of the suggestions and improved the manuscript. Although I still believe the discussion is shallow.
The authors confirmed that they recognized and mapped all types of landslides. Please insert a new column and include the landslide type information in Table 2.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
