Investigation of Slow-Moving Artificial Slope Failure with Multi-Temporal InSAR by Combining Persistent and Distributed Scatterers: A Case Study in Northern Taiwan

Round 1

Reviewer 1 Report

Dear editors, dear athors

This paper is a very interesting contribution to the understanding of a world famous landslide. An innovative insar technique has been applied to this site, bringing original information about the pre-failure deformation.
It is well written and pleasant to read. However I have a quite a number of small corrections to propose:

General comment: many figures are not at the right place. They are much too early in the text, sometimes several pages before the mention in the text. And Figure 10 should arrive at the beginning to understand the site.

L56: A “spirit level” is a specific tool, not really adapted to landslide monitoring. Tacheometers, theodolites or total stations will be used. You can also say more generally “topographical surveys”.

Figure 2: It’s better to indicate the orientation of a picture with letters (like E   --   W) inside the picture than with N arrows.

L93: indicate the coordinates Lat/long of the landslide. Not everybody know the Taiwanese freeway referencing system.

L96: indicate clearly on which side is the landslide (the steep one or the gentle one ?).

L100-101: the system of orientation is confusing. Use the system of strike and dip angle like after in the paper.

L107: a cross section would help to understand, with the topography before/after, the excavations. Or you should use the figure 10 here – it will help the reader to understand.

L114-115: it’s easier for the geologist to use angles than ratios to describe slopes

L134: what does “temporal resolution” mean ? is it the minimum temporal baseline ? For me temporal resolution would implies that you have at least one interferogram every 46 days (which is not the case).

L137: AW3D30m is a DEM I suppose ? define

Figure 4: define PS, DS and SHP in the legend

Figure 6: can you please say what is the red area on the left side ? 30mm/yr is a lot

Figure 7 is too small. Make it  as 5x3, and the (b) graph below with the time axis horizontal.

L254: “There”

L314-315: remove the sentence “The correlation … gravity”. There a plenty of retrogressive landslides, i.e. starting from the bottom.

L342: change “bedding plane angle” to  “bedding plane dip angle”

L342-345: reformulate. Difficult to  understand

Figure 10: Reorder the legend according to the superposition of layers. Draw the before failure topography. Pass the figure in black.

L362: not sure what you mean by oscillate. Be more precise.

L377: “four stages”

Author Response

Dear Reviewer:

The authors would like to thank the reviewer for his/her valuable comments and suggestions on the submitted manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to us. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red in the paper.

Best regards, roufei

Author Response File: Author Response.pdf

Reviewer 2 Report

The content of the article deals with a problematic of scientific interest but also at the level of forecasts related to the environment and the deformations that can occur on the globe. Specifically, the authors considered 15 images collected between 2007 and 2010 to find evidence of deformation before the massive collapse that occurred in 2010 in northern Taiwan. The results presented show the presence of a pre-landslide deformation in the period before the collapse. And they have shown that the temporal behavior of the movement is correlated in particular with local precipitation. The structure and organization of the contents of the paper are logical. The presentation of the problem, the objectives and the methodology are generally good. And the results presented showed the interest of the problem addressed and which could be useful in other remote sensing applications. However, apart from the application made in a specific context, it is very difficult to appreciate the added value of the article. Consequently, it would be useful to provide some clarifications to the questions and comments given below.
- It would be useful to present the problem first of all in a general way, a state of the art on different applications of the same kind. Then to present more specifically the application considered. This starts with the title, the summary, the general introduction ...
- 15 images have been considered, are they sufficient? why not consider other images collected in different frequency bands in order to improve the resolution and have other information to confirm the results obtained and / or to have more precise information on the observed deformations.
- It is important to indicate the limits of the methodology developed and applied within the framework of the application considered. And this according to, the sensor considered for the acquisition of the images, the quality and the volume of the images, the chosen polarization, the pre-processing and processing algorithms considered, the environment of interest, the attenuations due to the propagation. and clutter, topographic residues, ...
- It would be important to specify the algorithmic complexity of the methods used, and the calculation time required in the context of the simulations carried out.
- It would be important to specify how to implement the methodology developed in a practical and / or operational context.
- It would be important to rework the conclusion taking into account the previous remarks, and also it would be important to present the perspectives offered for the work presented.

Author Response

Dear Reviewer:

The authors would like to thank the reviewer for his/her valuable comments and suggestions on the submitted manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to us. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in red in the paper.

Best regards, roufei

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report