Updated Understanding of the Thompson River Valley Landslides Kinematics Using Satellite InSAR
Round 1
Reviewer 1 Report
The manuscript entitled 'Updated Understanding of the Thompson River Valley 2 Landslides Kinematics Using Satellite InSAR' is in a very interesting topic. The manuscript is not well constained and suffers from 'structural problems' and problems in the methology and especially the authors do not provide details about some parts of the methodology.
My major comments are listed below:
First, in the introduction section, the part of the literature's overview must be enriched. Also, a lot of citations in the main body of the manuscript are not showed in the References. Also, a lot of problems with the citation occured in many lines.
Line 28: the reference has the marker a, this does not correspond to the list of references.
Line 36: The reference Macciota et al., 2016 is not appeared in the list of references in the end of the manuscript.
Line 42-43: All these references are not appeared in the list of references in the end of the manuscript.
Line 48:The reference Macciota et al., 2016 is not appeared in the list of references in the end of the manuscript.
Line 50-51: Same problem with the references.
Line 52-53: Please rephrase, use more formal way to expressed this.
Line 54-58: Please rephrase the whole paragraph, it is confusing.
Line 82: the reference has the marker b, this does not correspond to the list of references
Line 85-92: Provide reference papers for this paragraph.
Line 110-112: Same problems with the references (not in the list).
Line 118-119: Same problems with the references (not in the list).
In figure 1 please put a scale on it.
In the section Material and methods, the methodology is not described properly. Please provide more details about the main processing from TER and the method that they used to produced the velocities maps of each landslide.
Line 169-182: I am lost in the description, please be more specified. Also, in line 177 provide the citation in the list of references.
In the equations 5 and 6, you calculated the look unit vector. You use the same look unit vector for the whole region? The incident angle along the sentinel images is changing, so if you use the same unit vector in the whole region, that is wrong.
My main concern is that you don't describe how you choose to separate the velocities in each landslide. Please provide how you did that and with what terms. In line 207-208, I don't like the idea, when the authors do not describe how the decision-making process were done. Please provide extensive details.
Line 228-229: Also, problems with the references, please check it.
The section 'results' is quite enormous. I suggest to move some of these in the supplementary material and provide here a summary of these with the main findings. Also, all the sections show the geology underneath. these are the real depths of the geological formations? From where did you get these data (from boreholes?) or they are schematic cross sections?
For better presentation of the results, make more clear where these cross section are located in the main map of each landslide.
In section of discussion, also I don;t understand how you choose the areas in which are calculated the R vectors.
Line 450: Again the reference is not provided in the list of references.
Line 499-502: Why this landslide has lower depth?
Author Response
“The manuscript entitled 'Updated Understanding of the Thompson River Valley 2 Landslides Kinematics Using Satellite InSAR' is in a very interesting topic. The manuscript is not well constrained and suffers from 'structural problems' and problems in the mythology and especially the authors do not provide details about some parts of the methodology.”
Thank you so much for reviewing the manuscript. Please see details how we addressed your comments below:
Comment 1) First, in the introduction section, the part of the literature's overview must be enriched. Also, a lot of citations in the main body of the manuscript are not showed in the References. Also, a lot of problems with the citation occured in many lines.
Response:
Thanks for your comment and we added some more details in the introduction to enrich this section (see the other reviewer response). We also have reviewed the references and it has been improved in the body of the manuscript.
Comment 2) Line 28: the reference has the marker a, this does not correspond to the list of references. Response:
It has been removed.
Comment 3) Line 36: The reference Macciota et al., 2016 is not appeared in the list of references in the end of the manuscript.
Response:
It is already done.
Comment 4) Line 42-43: All these references are not appeared in the list of references in the end of the manuscript. Response:
Thanks for your meticulously review on the manuscript and we reviewed all references and added all references.
Comment 5) Line 48:The reference Macciota et al., 2016 is not appeared in the list of references in the end of the manuscript.
Response:
It has been done.
Comment 6) Line 50-51: Same problem with the references.
Response:
It is already solved.
Comment 7) Line 52-53: Please rephrase, use more formal way to expressed this.
Response:
Thanks for your consideration and we have rephrased this sentence to introduce the outcome of the research. The manuscript now reads:
“In this paper an update on the landslides’ kinematics is presented based on the interpreted stratigraphy in the research area and InSAR monitoring data between May 2015 and May 2017[8,9,24,25,47,48].”
Comment 8) Line 54-58: Please rephrase the whole paragraph, it is confusing.
Response:
We have rephrased this paragraph. The manuscript now reads:
“To provide a practicable approach to approximate landslide displacement vectors, a combination of the geometry of Two InSAR orientations, and the assumed horizontal movement parallel to the average slope azimuth of each sector of each landslide are employed. This approach was validated for the area matter of this paper in Soltanieh et al. 2022 on the Ripley landslide, which has a long history of monitoring [11].”
Comment 9) Line 82: the reference has the marker b, this does not correspond to the list of references Response:
We have already removed it.
Comment 10) Line 85-92: Provide reference papers for this paragraph.
Response:
Thank you so much for you comment. All this paragraph is extracted from the same reference. We agree it is better to point the reference for each sentence separately and it has been added for each sentence. Now the manuscript reads:
“Using satellite InSAR data together with other monitoring information like precipitation or ground water fluctuation data can allow for a robust understanding of landslide mechanisms and possible triggers, and this method can be employed effectively to measure displacement of slow or extremely slow-moving slopes as well as capturing the initiation of acceleration [9].
Although satellite revisiting times (now approximately 3 days to 1 week) limit the temporal resolution of InSAR monitoring, good resolution of InSAR monitoring systems (sub-cm/year) makes it a very useful tool for monitoring landslides [9].”
Comment 11) Line 110-112: Same problems with the references (not in the list).
Response:
It is done.
Comment 12) Line 118-119: Same problems with the references (not in the list).
Response:
It has been done now.
Comment 13) In figure 1 please put a scale on it.
Response:
Thank you for your accuracy. It has been done.
Comment 14) In the section Material and methods, the methodology is not described properly. Please provide more details about the main processing from TRE and the method that they used to produce the velocities maps of each landslide.
Response:
Thanks for your comment on this section. The TRE group provided the LOS displacement data in the time span of the research by processing sentinel 1 data and the authors calculated the velocity of each sector of each landslide. The method for calculation of R vectors is explained in the methodology section of the manuscript. To explain the processing method by TRE we have added some more detail and you can see the response to reviewer 2.
Comment 15) Line 169-182: I am lost in the description, please be more specified. Also, in line 177 provide the citation in the list of references.
Response:
Thank you for your comment on these lines. It has been tried in these lines to explain the main calculation ideas and assumptions to find the real ground’s displacement vectors for each landslide. We now have modified this paragraph and also updated the citation in line 177 and the manuscript now reads:
“The true ground displacement is called “Real vector” and is represented by bold R to show it is a vector. The north-south displacement components are not considered reliable because the given orbits are sub-parallel to the north-south direction. Assuming R parallel to the downslope direction (both azimuth and inclination) is a common assumption for landslide InSAR interpretation [10]. In this paper, it is assumed that the horizontal component of R is parallel to the slope azimuth (average slope azimuth in the area of analysis). Therefore, the unit vector of the horizontal component of R can be calculated using the topography of the area. A digital elevation model (DEM) of the Thompson River valley was used in ArcMap [51] to calculate the average azimuth of the vector normal to the slope. Considering the vertical component of R as an unknown, the assumption of the horizontal component direction, and projecting R to the LOS unit vectors based on the satellite geometries for both satellite orbits; allows to calculate an approximation for all components of R. The following process is presented in Soltanieh and Macciotta [27].”
Comment 16) In the equations 5 and 6, you calculated the look unit vector. You use the same look unit vector for the whole region? The incident angle along the sentinel images is changing, so if you use the same unit vector in the whole region, that is wrong.
Response:
Thanks for your accurate comment in this section. Although we accept that the unit vector is different for each point of the landslide, the differences is negligible based on the satellite distance from the earth crust. So, we think this assumption does not have major effect on the results.
Comment 17) My main concern is that you don't describe how you choose to separate the velocities in each landslide. Please provide how you did that and with what terms. In line 207-208, I don't like the idea, when the authors do not describe how the decision-making process were done. Please provide extensive details.
Response:
Thanks for sharing your concern on this section and we have added some more details to explain the main idea behind the selecting sectors on landslides. The manuscript now reads:
“It was mentioned that the spatial and temporal inconsistency between ascending and descending InSAR data required spatial and temporal averaging. Spatial averaging considered segmentation of the landslides that balanced data density (e.g., availability of both ascending and descending orbits’ data) and covering different portions of the landslide to allow kinematic interpretation. This decision-making process was done qualitatively and based on the experience of the authors from their other research [27]. Figure 3 shows the data density for all investigated landslides. It is shown that almost all these areas contain more than one scatterer of each orbit, and the average of these scatterers are used as representative of LOS displacements for the area. “
Comment 18) Line 228-229: Also, problems with the references, please check it.
Response:
It has been done.
Comment 19) The section 'results' is quite enormous. I suggest to move some of these in the supplementary material and provide here a summary of these with the main findings. Also, all the sections show the geology underneath. these are the real depths of the geological formations? From where did you get these data (from boreholes?), or they are schematic cross sections?
Response:
Thank you so much for your great comment. We agree that the results section is huge, but the area of research contains 6 landslides along the Thompson River Valley, and it could be the reason for the volume of presented results. We have already tried to summarize the results and the figures increased the volume of this section of the manuscript. We still believe it is better for readers to have all these results in the main body of our manuscript to avoid confusion. The Geology also is inspired by one of our references and it is presented in Eshraghian et al 2007.
Comment 20) For better presentation of the results, make clearer where these cross section are located in the main map of each landslide.
Response:
Thanks for this comment. We have tried to show the location of each cross section on top of all figures. Although it is a little too small, we decided to leave it there to avoid to add lots of figures for only showing the location of each cross section.
Comment 21) In section of discussion, also I don;t understand how you choose the areas in which are calculated the R vectors.
Response:
Thanks for your comment and we have tried to provide more details about essential conditions to find R vectors for each sector which guided us to select the sectors on each landslide. The manuscript now reads in discussion section:
“Although the density of gathered data are different for each landslide in the research area, Figure 3 shows the data density guided selection of landslide sectors to balance information adequacy and availability for kinematic analysis. To calculate the R Vectors, we require data from both orbits within each sector, where sectors are defined such that data density is enough for all defined sectors of each landslide. The exception in this research was sector 2 of the Goddard landslide, with a lack of descending orbit data.”
Comment 22) Line 450: Again, the reference is not provided in the list of references.
Response:
It has been done now.
Comment 23) Line 499-502: Why this landslide has lower depth?
Response:
We have tried to interpret the possible sliding surface of each landslide using the calculated R vectors for each selected sector and the landslide geometry and subsurface layers. We believe the location of this landslide which is relatively farther than other landslides from the Thompson River, can affect the depth of the shearing surface. Also, the slope of the ground is less steep, and it can also affect the shearing surface for this landslide.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper offers a good overview of landslide activity as derived from InSAR data. It can be accepted after minor revisions. My comments can be found in the attached pdf.
Comments for author File: Comments.pdf
Author Response
Thompson River Valley Manuscript Reviewer 2 Responses:
“The paper offers a good overview of landslide activity as derived from InSAR data. It can be accepted after minor revisions. My comments can be found in the attached pdf.”
Thank you so much for reviewing the manuscript and for your encouraging words.
Please see details how we addressed your comments below:
Comment 1) subsurface
Response:
Thanks for your comment and it has been done. The manuscript now reads:
“The subsurface interpretation of these landslides is combined with satellite InSAR data from May 2015 to May 2017 to enhance the current understanding of the landslide kinematics.”
Comment 2) from May 2015 to May 2017.
Response:
Thanks for your comment on the detail but we believe keeping the data time span in abstract will help readers to know more in detail about the research time span and we prefer to leave the time line here.
Comment 3) that
Response:
Thank you so much for your comment. We decided to hold the letter of “the” here because the sentence present our idea properly in this section.
Comment 4) this is not MDPIreference format. Check the author guidelines
Response:
Thanks for your comments on the references’ format and we have reviewed all references and changed them based on the Journal’s format. You can also see the responses to the other reviewer.
Comments 5) (These correspond to InSAR processed datasets that 52 were made available).
Response:
Thank you for your suggestion. We have removed the phrase because it does not affect the main idea of the research.
Comment 6) some papers reviewing insar usage for landslides to enrich the reference list:
_ Solari, L., Del Soldato, M., Raspini, F., Barra, A., Bianchini, S., Confuorto, P., ... & Crosetto, M. (2020). Review of satellite interferometry for landslide detection in Italy. Remote Sensing, 12(8), 1351.
_ Zhao, C., & Lu, Z. (2018). Remote sensing of landslides—A review. Remote Sensing, 10(2), 279.
_ Lu, Z., & Kim, J. (2021). A framework for studying hydrology-driven landslide hazards in northwestern US using satellite InSAR, precipitation and soil moisture observations: early results and future directions. GeoHazards, 2(2), 17-40.
Response:
Thanks for your comment on this section and we have added some more references here to enrich the references list as well as to show the worldwide application of the InSAR method. Now the manuscript reads:
“Interferometric synthetic aperture radar (InSAR) has been used in many worldwide applications to detect surface displacements of crustal deformation, glacier motion, infrastructure displacement and landslides in recent decades (Herrera et al., 2012, Colesanti et al., 2006, Vadivel et al., 2020, Abe et al., 2020, Motagh et al., 2017, Hooper et al., 2011, Chen et al., 2022, Liu et al., 2022, Mastro et al., 2022, Abdel-Hamid et al., 2021, Dumka et al., 2020, Castellazzi et al., 2020, Solari et al., 2020, Zhao et al., 2018, Lu et al., 2021).”
Comment 7) more information about the InSAR processing is required. It is not enough to say that the data were processed with SqueeSAR.
Response:
Thanks for your great comment here and we have added some more detail about data processing by TRE and now the manuscript reads:
“InSAR data is impacted by topographic distortions, atmospheric effects, and other sources of noise. The Differential InSAR (DInSAR) can be employ to identify and quantify ground movement by removing topographical effects using a DEM of the area of interest. The accuracy of this method is reletively low (cm scale). The atmospheric noises can be removed by the Permanent Scatterer SAR Interferometry (PSInSAR) method, which is an advanced form of DInSAR. The accuracy of this method is higher than DInSAR (milimetre accuracy) and a history of both linear and non-linear ground motion can be detcted. The PSInSAR was developed to detect the motion of PS data. The algorithms developed by TRE include the use of SqueeSAR, which incorporates PSInSAR to also process the signals reflected from DS areas. This algorithm effectively reduces noise in data and keep the accuracy in the milimetre scale (TRE Group report for the Thompson River Valley., 2018).”
Comment 8) the points are barely visible and it is impossible to distinguish the 2 orbits. Please improve this figure.
Response:
Thank you for your comment on figure 3 and we have improved it.
Comment 9) displacement
Response:
It has been Done.
Comment 10) place the points on top of the image, without transparency. Comment valid for all the similar figures.
Response:
Thank for you comment on this Figure but our focus in this figure is on introducing the horizontal component of calculated R vectors for each sector of landslides and changing the transparency may have negative effect and make it confusing and hard to read for reader. Therefore, we decided to keep these Figures unchanged.
Comment 11) This can be removed, it is unreadable. Comment valid for all the figures.
Response:
Thank you for your accuracy in reviewing the manuscript and the aim of the schematic of landslide on these section views is showing the location of selected sections on each landslide and keeping it seems necessary. So, we decided to include these schematic on these figures.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors addressed all of my comments!
Now the paper is ready for publication!
