V_s30 Prediction Models Based on Measured Shear-Wave Velocities in Tangshan, China

Round 1

Reviewer 1 Report

1. Please confirm the significance of this paper in the actual field. The content of the paper does not match the title and abstract.

2. The paper does not give a clear explanation of the three proposed models, and it is suggested to add more introduction to the models.

3. The research methods and conclusions of the paper are not enough to predict V_s30. The content of the paper is not sufficient and the conclusions are not convincing,

4. A more in-depth explanation is needed on the conclusions.

5. The author designed three models to get good results, which is desirable in the research method, and hopes to add more details.

To sum up, the competitiveness of this paper is far from enough, and I don't think it can be published at present.

Author Response

Reviewer #1:

1. Please confirm the significance of this paper in the actual field. The content of the paper does not match the title and abstract.

Reply1: (1)Thanks for your comments. In the abstract introduction, we confirm the significance of this paper in the actual field.

(2) Your opinion is very valuable. We have modified the content and abstract of the paper according to your comments, so as to match the title of the paper more accurately.

 

2. The paper does not give a clear explanation of the three proposed models, and it is suggested to add more introduction to the models.

Reply2: Thanks for your comments. In the second and sixth part of this paper, we will give a more detailed description of the proposed model.

3. The research methods and conclusions of the paper are not enough to predict V_s30. The content of the paper is not sufficient and the conclusions are not convincing.

Reply3: Thanks for your comments. It may be that the description of this paper makes you misunderstand. We have revised the content of the paper in order to better express the true intention of the paper. In fact, the prediction model in this paper has been applied to the engineering practice in Tangshan area, and the prediction results are very good.

 

4. A more in-depth explanation is needed on the conclusions.

Reply4: Thanks for your comments. We have revised the conclusions of this article, especially the scope and applicability of this article.

 

5. The author designed three models to get good results, which is desirable in the research method, and hopes to add more details.

Reply5: Thanks for your comments. First of all, we add further explanations of three models in the second and sixth parts of the paper; Then, in the abstract and conclusion part, the applicability of the model established in this paper is supplemented, so that it can be better applied.

 

Reviewer 2 Report

The text deals with determining the constant coefficients for estimating the shear wave velocity equivalent to the upper 30 meters of the ground, in incomplete borehole conditions. In this research, two approaches have been used including the topographic slope and the relations based on the shear wave velocity at lower depths. These approaches were supported by 343 boreholes data with a depth of more than 30 meters in the Tangshan region of China.

 

The topic is interesting and practical, although no new model was presented and the study only aims to present the suitable constant coefficients corresponding to the existing models in the technical literature. The English language is not fluent, it needs editing. Finally, the text, tables, and materials presented need major corrections before being accepted for publication.

The comments are as follows:

Abstract:

1. The text is not fluent and continuous. It is necessary to present the research results not by numbering but continuously.

2. Considering today's development of accurate subsurface detection methods based on the propagation of weak and strong ground motion waves in sites without the need to drill boreholes, please explain the novelty aspect of the work in the abstract, introduction, and conclusion.

3. Please, introduce the abbreviations in the first appearance in the text (e.g., BCV).

4. First, present the titles of all the methods that have been investigated, then introduce the best methodology. Here, in addition to the topographic slope method and Vsz, the names of several other methods are given which are a subset of the Vsz method; but this separation cannot be established in the abstract. Please rewrite the abstract.

 Keywords:

5. It is suggested to use words instead of abbreviations.

 6. Line 117: The reference should be Shafiee et al.

7. Line 149: The soil of the studied area, is mainly soft soil with low shear wave velocity. The main problem in drilling boreholes down to a depth of 30 meters for most areas occurs in conditions where the ground is hard and dense with high shear wave velocity and the possibility of drilling is not easily available, and the cost of drilling increases. In such cases, engineers go to empirical correlations. This database does not include high shear wave velocity. Please, mention in the title of the manuscript that these relationships are presented for low shear wave velocity or complete the database for high shear wave velocity range.

8. Line 166 and Figure 3: The figure on the right is for 90 meters. Introduce the figures by naming them (a) and (b) separately.

9. Line 171: The fourth division is called D3 in the text, however, it was called C1 in Figure 3.

10. Line 252: In Table 1, the introduced constants are a and b; While equation (2) introduces two constants a0 and a1, equation (3) introduces three constants b0, b1, and b2, and for method [19] no equation or constant is introduced. The constants used for Figure 8 should be presented in the table. In tables 1 and 2, name the coefficients based on the equations. In addition, it is necessary to introduce the equation used in this study.

11. Line 254: Do you mean Figure 8?

12. Line 271: It was better that some data were not used in determining the regression constants, and the performance of the equations was determined blindly with the group of data that was not used. How much the match between the models and observations is realistic?

13. Table 2: It is better to present Table 2 before Figure 9.

14. Line 305: Introduce the abbreviation associated with the parameters presented in Figure 12 in the text.

15. References: Please add the DOI of articles to the references.

 

16. Reference [27] is "A. Shafiee, H. Zafarani, M. Jahanandish"

Author Response

Reviewer #2:

The text deals with determining the constant coefficients for estimating the shear wave velocity equivalent to the upper 30 meters of the ground, in incomplete borehole conditions. In this research, two approaches have been used including the topographic slope and the relations based on the shear wave velocity at lower depths. These approaches were supported by 343 boreholes data with a depth of more than 30 meters in the Tangshan region of China.

 The topic is interesting and practical, although no new model was presented and the study only aims to present the suitable constant coefficients corresponding to the existing models in the technical literature. The English language is not fluent, it needs editing. Finally, the text, tables, and materials presented need major corrections before being accepted for publication.

The comments are as follows:

Abstract:

1. The text is not fluent and continuous. It is necessary to present the research results not by numbering but continuously.

Reply1: Thanks for your comments. According to your suggestion, we have deleted the number in the summary.

2. Considering today's development of accurate subsurface detection methods based on the propagation of weak and strong ground motion waves in sites without the need to drill boreholes, please explain the novelty aspect of the work in the abstract, introduction, and conclusion.

Reply2:Thanks for your comments. According your suggestion, we have explained the novelty aspect of the work in the introduction and conclusion. In addition, although some studies have suggested that seismic motion can predict shear wave velocity without drilling, due to the scarcity of seismic records, the prediction is not very good.

 

3. Please, introduce the abbreviations in the first appearance in the text (e.g., BCV).

Reply3: Thanks for your comments. We have added the explanation of BCV in the abstract.

4. First, present the titles of all the methods that have been investigated, then introduce the best methodology. Here, in addition to the topographic slope method and Vsz, the names of several other methods are given which are a subset of the Vsz method; but this separation cannot be established in the abstract. Please rewrite the abstract.

Reply4: Thanks for your comments. We have rewritten the abstract.

 Keywords:

5. It is suggested to use words instead of abbreviations.

Reply5: Thanks for your comments. We change the keywords.

 

6. Line 117: The reference should be Shafiee et al.

Reply5: Thanks for your comments. We fix the error.

7. Line 149: The soil of the studied area, is mainly soft soil with low shear wave velocity. The main problem in drilling boreholes down to a depth of 30 meters for most areas occurs in conditions where the ground is hard and dense with high shear wave velocity and the possibility of drilling is not easily available, and the cost of drilling increases. In such cases, engineers go to empirical correlations. This database does not include high shear wave velocity. Please, mention in the title of the manuscript that these relationships are presented for low shear wave velocity or complete the database for high shear wave velocity range.

Reply7: Thanks for your comments. In the abstract and conclusion of the paper, we supplement the limitations of the prediction model in this paper as: these prediction models are applicable to areas with relatively low shear wave velocity, because the data used in this paper is from Tangshan, where the shear wave velocity is generally not high. So we don’t modify the tile of this paper.

 

8. Line 166 and Figure 3: The figure on the right is for 90 meters. Introduce the figures by naming them (a) and (b) separately.

Reply8: Thanks for your comments. We modify Line 166 and Figure 3.

 

9. Line 171: The fourth division is called D3 in the text, however, it was called C1 in Figure 3.

Reply9: Thanks for your comments. The fourth division is called D3. We modify the Figure 3.

 

10. Line 252: In Table 1, the introduced constants are a and b; While equation (2) introduces two constants a0 and a1, equation (3) introduces three constants b0, b1, and b2, and for method [19] no equation or constant is introduced. The constants used for Figure 8 should be presented in the table. In tables 1 and 2, name the coefficients based on the equations. In addition, it is necessary to introduce the equation used in this study.

Reply10: Thanks for your comments. The coefficients should be a0 and a1 In tables 1. The coefficients should be c0 and c1 In tables 2. In addition,we also used the equation 2 and 3 in this study.

 

11. Line 254: Do you mean Figure 8?

Reply11: Thanks for your comments. We change Figure 8 to Figure 5 on line 254.

 

12. Line 271: It was better that some data were not used in determining the regression constants, and the performance of the equations was determined blindly with the group of data that was not used. How much the match between the models and observations is realistic?

Reply12: Thanks for your comments. As you said, it is necessary to verify the validity of the model.The LLH verification method adopted in this paper allows the databased selection of a best model and a ranking and weighting of the remaining models in a pre-defined set. The remaining models in a pre-defined set. Shafiee et al. showed that this method can effectively select the optimal model of Vs30 prediction.

 

13. Table 2: It is better to present Table 2 before Figure 9.

Reply6: Thanks for your comments. We change the order.

 

14. Line 305: Introduce the abbreviation associated with the parameters presented in Figure 12 in the text.

Reply6: Thanks for your comments. We introduce the abbreviation associated with the parameters presented in Figure 12 in the text.

 

15. References: Please add the DOI of articles to the references.

Reply6: Thanks for your comments. According to the requirements of the, it is not necessary to add the DOI of articles.

16. Reference [27] is "A. Shafiee, H. Zafarani, M. Jahanandish"

Reply6: Thanks for your comments. We modify this mistake.

Author Response File: Author Response.doc

Reviewer 3 Report

The paper proposes an approach to predict Vs30 based on measured shear-wave velocities in Tangshan, China. In the reviewer’s opinion, the paper deals with an interesting and import topic. Results of this paper are very interesting. The paper can be published if the following comments are well addressed:

1. Vs30 prediction is very meaningful, especially for seismic performance assessment or design of structures in a regional scale as discussed in (Xu et al: doi.org/10.1002/eqe.3699). It is suggested to solid the background of this study.

2. Black dots in the fig 1 are too small to read. This figure is suggested to plot more clearly. What does the “u” in this figure mean?

3. Figure 5, what do the lines mean? We cannot clearly understand the black lines in this figure.

4. Why the axis of fig 6 are not equally arranged? For instance, the distance between 100 and 200 are larger than that of 200 and 300.

5. What does the “datd” mean in fig 8 and fig 9 mean?

6. Application limitations of the proposed approach are suggested to be given.

Author Response

Reviewer #3:

The paper proposes an approach to predict Vs30 based on measured shear-wave velocities in Tangshan, China. In the reviewer’s opinion, the paper deals with an interesting and import topic. Results of this paper are very interesting. The paper can be published if the following comments are well addressed:

1. Vs30 prediction is very meaningful, especially for seismic performance assessment or design of structures in a regional scale as discussed in (Xu et al: doi.org/10.1002/eqe.3699). It is suggested to solid the background of this study.

Reply1: Thanks for your comments. We added this paper in the introduction.

2. Black dots in the fig 1 are too small to read. This figure is suggested to plot more clearly. What does the “u” in this figure mean?

Reply2: Thanks for your comments. We modify the figure 1 to plot more clearly. In addition, we don’t find a u in figure 1.

 

3. Figure 5, what do the lines mean? We cannot clearly understand the black lines in this figure.

Reply3: Thanks for your comments. The lines form polygons which represent the scope of Vs30 in the tectonically unstable zone determined by Wald and Allen corresponding to the topographic slope

 

4. Why the axis of fig 6 are not equally arranged? For instance, the distance between 100 and 200 are larger than that of 200 and 300.

Reply4: Thanks for your comments. The axis in Figure 6 is logarithmically increasing.

 

5. What does the “datd” mean in fig 8 and fig 9 mean?

Reply4: Thanks for your comments. There are some mistakes. We change the “datd” to “data”.

 

6. Application limitations of the proposed approach are suggested to be given.

Reply4: Thanks for your comments. We apply the limitations of the proposed approach in abstract and conclusion.

 

Author Response File: Author Response.doc

Reviewer 4 Report

Comments for author File: Comments.pdf

Author Response

Reviewer #4

 

I think that this paper is good and the methodology for Vs30 prediction models based on measured shearwave velocities in Tangshan, China is very promising. However, some remarks can taken into account to improve the article:

1. The English is correct in general. Paper written well.

Reply1: Thanks for your comments.

2. Few typos must corrected:

(1)Line 64: add point instead comma.

(2)Line 102: C0 and C1 must written in lowercase letter like in Eq.4.

(3)In Figure 7 and Figure 11, correct abscise axe Vs30 by Vs30obsv.

Reply2: Thanks for your comments.

(1) We have added point instead comma.

(2) We have written them in lowercase letter.

(3) We have corrected these mistakes.

 

3.BCV model was not explain very well in the paper. Add more details is very appreciate.

Reply3: Thanks for your comments. We have explained the BCV model more well as: For the constant-velocity extrapolation model, The main assumption of the BCV model is that Vs is constant from z to 30 m as given by:

                      (1)

 

4. For linear prediction model, presented equations of Vs30 for every depth of soil is unsuitable.Because, linear prediction model show clearly that regression parameters (a, b) depend of thevariation of the depth. To improve this predicted model, add a new figure that show the variationof (a, b) versus the depth of the soil. After, you can obtained a new linear prediction model (onequation valuable for all depths) by introduced the new relations of the regressionoefficients a and b) versus depth in the linear model.

Reply4: Thanks for your comments.(1) Your suggestion is a great improvement on our linear model. In fact, we have tried many methods to improve the linear model, but since there are only 19 regression coefficients of different depths, the data are too discrete to obtain the relationship between regression coefficients a, b and depth. (2)The purpose of this paper is to establish different prediction models applicable to various depths, and to obtain the optimal model of a specific depth. Although your suggestions can greatly optimize the linear model, it is not convenient to compare and analyze the previous models and other models in this study at multiple depths, so the optimal model of a certain depth cannot be obtained. In general, the depth of Vs data is different for different boreholes, so it is necessary to give a linear regression model for a particular depth.

 

5. Details on the calculation code (Matlab, Excel) do not exist in the paper. The addition of aparagraph presenting the calculation code is essential.

Reply5: Thanks for your comments. In general, most models need to be built through programming. Because the model proposed in this paper is relatively simple, only simple excel functions are used in coefficient regression and VS30 calculation. This also reflects from the side that the model established in this paper is concise and effective, and can be better applied in engineering.

 

Author Response File: Author Response.doc

Round 2

Reviewer 2 Report

Line 16: To introduce abbreviations, the full title must come first in the first appearance before the abbreviation, and the abbreviation must be placed in parentheses.

Author Response

Reviewer #2:

Line 16: To introduce abbreviations, the full title must come first in the first appearance before the abbreviation, and the abbreviation must be placed in parentheses.

Reply: Thanks for your comments. We place the abbreviation in the parentheses.

Reviewer 4 Report

 After that the authors were took in consideration all my remarkes, I accept the publication of this paper in this form.

Author Response

Reviewer #4:

 After that the authors were took in consideration all my remarkes, I accept the publication of this paper in this form.

Reply: Thank you.