Surface Rupture Kinematics and Coseismic Slip Distribution during the 2019 Mw7.1 Ridgecrest, California Earthquake Sequence Revealed by SAR and Optical Images

Round 1

Reviewer 1 Report

I accept the article, after the authors have corrected the new citation n.44. The authors have reversed the names with surnames of the authors. The right citation is as follows:

Mastro, P.; Serio, C.; Masiello, G.and Pepe, A. The Multiple
Aperture SAR Interferometry (MAI) Technique for the Detection of
Large Ground Displacement Dynamics: An Overview. Remote Sens. 2020,
12(7), 1189.

Please, correct this and then the paper is acceptable.

Author Response

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Reviewer 2 Report

Authors answered satisfactorily to all questions.

 

Author Response

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Reviewer 3 Report

The authors in this paper propose an interesting approach to identify surface rupture trace and some significant surface rupture by using the curl and divergence of the field component. In addition they spice up the manuscript with the analysis on the slip along the fixed faults and the related coulomb stress on the Garlock fault. However, I think that some criticism already exists. Following, I list my comments.

• Could we see the comparison between the GPS data displacements with your retrieved deformation components? With your analysis, you can estimate the horizontal displacement for each pixels on the map.
• There is an error in the mathematical formalism of divergence equation.
• I think that, because of the main goal of the paper is to identify surface rupture trace and some significant surface rupture by a precise and easy method (used the curl and divergence maps), is fundamental to show a synthetic case (model) in which you demonstrate their (curl and divergence) congeniality to this event.
• In order to show the validity of your analysis about the slip distribution along the faults (Paragraph 4) it is necessary to add a map with the comparison between your retrieved displacement dataset and the modelled one.

Best regards.

Author Response

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Round 2

Reviewer 3 Report

The authors improve their manuscript following almost all my comments. Unfortunately, i am not able to explain them the error in formula at line 206 (question 4). For this reason i attach a page of (Zhou, Y. et al, 2018) manuscript, to show them how modify it.

best regards

Comments for author File: Comments.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The article of Chenglong Li et al. is very interesting and, in my opinion, the most innovative aspect is the using of the curl and divergence to retrieve the horizontal component of such a kind complex fault systems; this analysis can be extended to similar faults over the Earth.

Therefore, I recommend publishing after the following points are better clarified:

Line 115: compute, not ‘computer’

Lines 122-123: the authors write: ‘The distribution and structure of the footwall and hanging wall rupture motions are asymmetric, with more displacements on the west of the rupture trace’, but this is not clear from the figure 2a;

Line 124: epicenter and not hypocenter;

Line 124: ‘peaks at ~4.6m’, but I don’t see this value from the figure 2;

Figure 2: report also the epicenter of the Mw7.1 event

Figure 5: (a), (b) and (c) are missing in the panels

Finally, I would like to point out to the authors that an article (https://www.mdpi.com/2072-4292/12/7/1189) which uses the MAI technique to reconstruct the North-South component of the Ridgcrest earthquake, is recently come out. I suggest to the authors to comment any similarities or discrepancies among their results and those achieved by the other researchers; this comment may be inserted at the end of the paper, in the Discussion section.

Author Response

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Reviewer 2 Report

Block diagram using SAR processing is missing. Atmospheric correction are done properly?. Gamma software is outdated. Provide the latest references to the Gamma software.

Is there any comparison made using ground measurements?

Is there any further correction needed for Sentinel 2 data. Probably it depends on weather, clouds, moisture, atmosphere condition in that time. In Computer vision algorithms there exist many algorithms for flow estimation. How are those algorithms efficient compared to the used method? A processing chain could be depicted using a block diagram.

Is there any vegetation at specific area. What was average coherence for interferogram generation?

Paper needs technical English review, sometimes some sentences are difficult to understand.

Many of conclusions are made using the proposed processing chain and a lot of conclusion are cited. Processing was done using several different software, designed for a specific tasks. A clear processing chain should be clarify and novelties of the proposed paper should be clearly highlighted.

Author Response

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Reviewer 3 Report

The authors study the 2019 Ridgecrest, California earthquake sequence. In order to characterize the surface rupture kinematics and fault slip distribution, they use optical images and InSAR observations.

The work is well organized and comprehensively, but there are some aspects to improve. My comments:

 1) The NS data from optical image seems to be more stable than the EW one. Did you use a multilook process to reduce the line effect?

2) Did you consider the GPS measurement to compare your observations (NS, EW)?

3) Why didn't you estimate the UP and EW components from the InSAR data? you could compare it with that comes from optical images or solve a linear equation system.

4) There is an error in the equation  of divergence.

In addition, i suggest to add a synthetic case (model) in which you show their (curl and divergence) congeniality to this event.

5) The description of the considered six faults is misleading. Please add a new table with the six faults, highlighting the main ones from the ancillary ones.

In figure 7 the fault III is not indicated.

6) The description of the considered six faults is misleading. Please add a new table (2) with the six faults, highlighting the main ones from the ancillary ones. In table 1 you could show only the segments.

7) Did you perform a non-linear inversion of the six faults by fixing their retrieve parameters (Length, strike, dip and position)? So that you obtain restricted estimations of the others.

Not for the quality of the work, but for some important clarifications, i suggest major revision.

best regards

minor: 

line 257 "and. we We"

line 419 "introducing"---> calculating

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Suggested comments are not included, presented and discussed in the revised manuscript, therefore, major revision is still needed.

Reviewer 3 Report

I am disappointed from the authors superficiality in making the answers.

For further clarifications, please see the attached file with my report.

best regards

 

Comments for author File: Comments.pdf