An MT-InSAR-Based Procedure for Detecting and Interpreting Vertical Ground Deformation Anomalies During Phases of Unrest at Campi Flegrei Caldera, Italy
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis study presents A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in active volcanic caldera.
It is a most interesting technical paper with a rich literary underpinning and is well written. The Abstract is a fair synopsis of the paper though without disrespect to the authors the novelty of the work should be reinforced in the Introduction and conclusions.
So far as this reviewer is concerned the approach to the study is robust and includes a wise caveat in the Abstract of the potential of what the method could offer (lines 26 to 29) instead of asserting definitive proof.
In this reviewer’s view the paper could be strengthened by considering the following.
Lines 3 and 4, should the title read A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in an active volcanic caldera?
Consider line 18. The authors seem to use two different ways of saying the same thing and do so frequently throughout the paper if maximum uplift point is equivalent to deformation center then say so or choose one or the other?
Consider line 24. The authors use the terms GPS and GNSS in the paper as if they are interchangeable. Could the authors review their paper and ensure that they are being consistent.
Line 79. Should RITE GNNS read RITE GNSS?
Consider line 90. Consider substituting GNSS (Global Navigation Satellite System) for Global Navigation Satellite System (GNSS) and similarly throughout the paper.
Line 108. Do the authors mean westward or perhaps west of Naples?
Line 149. Do the authors mean BC?
Line 204. Consider replacing 2000’s with 2000s and omit years. On the other hand, if this is a direct citation then insert the abbreviation for spelling is correct (sic).
Line 233. ArcGIS Pro or ArcGIS PRO (line 244)? If I understand the Esri website correctly it is ArcGIS Pro. Please be consistent.
Lines 237 to 238. A standard deviation of 69.77 seems high and could the authors comment on the reliability of their data therefore as it could be potentially fatal to the paper?
Lines 271 to 275. In a literature rich paper, could the authors provide one or two references here otherwise the statements become unsupported assertions.
Line 288. Do the authors mean Figures 3 and 5?
Line 309. This is a little unclear, at least to this reviewer. Could the authors please reword or expand on is estimated in 3mm?
Line 311. Could the authors please expand a little on the best-fitting sixth degree polynomial? Broadly speaking, a sixth order polynomial can be made to fit almost anything.
Line 347. Do the authors mean radial pattern?
Line 371. Should geometrically read geometric?
Figure 9. The polynomial curve is indistinct. Could the authors use a different colour like yellow or something to increase the contrast?
Lines 375 to 376. Is there any reason that r and N are in quotation marks?
On a general point, the authors’ sentences are rather long, sometimes circa 60 words. It would be helpful, it seems to this reviewer, if the authors could be more succinct.
Notwithstanding my aforementioned comments this is a good paper that would benefit in particular from attention to lines 237-238 in particular.
I trust the authors find these comments helpful and constructive.
Comments on the Quality of English LanguageThe English was a little longwinded with some sentences @ 60 words. I would respectfully encourage authors to be succinct and get to the point. It might commend their papers to a wider readership.
Author Response
Comments and Suggestions for Authors
This study presents A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in active volcanic caldera.
It is a most interesting technical paper with a rich literary underpinning and is well written. The Abstract is a fair synopsis of the paper though without disrespect to the authors the novelty of the work should be reinforced in the Introduction and conclusions.
So far as this reviewer is concerned the approach to the study is robust and includes a wise caveat in the Abstract of the potential of what the method could offer (lines 26 to 29) instead of asserting definitive proof.
In this reviewer’s view the paper could be strengthened by considering the following.
REPLY – Thanks to the reviewer for his useful comments and suggestions
Lines 3 and 4, should the title read A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in an active volcanic caldera?
REPLY – The title has been actually changed, as suggested, in order to better reflect the paper content which is mostly focused on Campi Flegrei caldera.
Consider line 18. The authors seem to use two different ways of saying the same thing and do so frequently throughout the paper if maximum uplift point is equivalent to deformation center then say so or choose one or the other?
REPLY – We have corrected throughout the text in “deformation center”. The maximum uplift point should be equivalent to deformation center, but the maximum uplift is actually unknown because the deformation center falls slightly offshore, whereas uplift is only measured onland (except on few points on some buoys).
Consider line 24. The authors use the terms GPS and GNSS in the paper as if they are interchangeable. Could the authors review their paper and ensure that they are being consistent.
REPLY – We are aware that the two terms (GPS and GNNS) are not interchangeable. We used the term GNSS in Introduction section for reference to the results of other published papers [i.e. 17,100]. We have used a GPS dataset published in [81,82] for cross-checking the InSAR results so we use the term GPS when referring to this dataset.
Line 79. Should RITE GNNS read RITE GNSS?
REPLY – yes, we corrected it.
Consider line 90. Consider substituting GNSS (Global Navigation Satellite System) for Global Navigation Satellite System (GNSS) and similarly throughout the paper.
REPLY – see reply to line 24
Line 108. Do the authors mean westward or perhaps west of Naples?
REPLY – yes, we corrected it.
Line 149. Do the authors mean BC?
REPLY – yes, we corrected it.
Line 204. Consider replacing 2000’s with 2000s and omit years. On the other hand, if this is a direct citation then insert the abbreviation for spelling is correct (sic).
REPLY – ok, we did it.
Line 233. ArcGIS Pro or ArcGIS PRO (line 244)? If I understand the Esri website correctly it is ArcGIS Pro. Please be consistent.
REPLY – Ok, we did it.
Lines 237 to 238. A standard deviation of 69.77 seems high and could the authors comment on the reliability of their data therefore as it could be potentially fatal to the paper?
REPLY – Here there is a misunderstanding, which is our fault. The standard deviation quoted here is not related to the mean square error between data and model: it is the standard deviation of the dataset, just because uplift values range in 2016-2021 from about 55 cm (at the Pozzuoli port) and almost zero at large distance from it. A high standard deviation simply indicates a wide range of data values, while a low standard deviation would indicate a narrow distribution of values clustered around the mean of the data set. There is in fact no problem with the reliability of data and model; the associated measurement uncertainties can be estimated by the RMSE (Root Mean Square Error) values having a mean value of 1.18 mm, as reported some lines below.
Lines 271 to 275. In a literature rich paper, could the authors provide one or two references here otherwise the statements become unsupported assertions.
REPLY – These statements are our original definitions for explaining the criteria of the adopted procedure. No reference is necessary.
Line 288. Do the authors mean Figures 3 and 5?
REPLY – Yes, we do.
Line 309. This is a little unclear, at least to this reviewer. Could the authors please reword or expand on is estimated in 3 mm?
REPLY – The sentence has been rewritten in a clearer way.
Line 311. Could the authors please expand a little on the best-fitting sixth degree polynomial? Broadly speaking, a sixth order polynomial can be made to fit almost anything.
REPLY – We have used a criterion based on the RMSE, as explained in the revised version of the paper, for selecting the best polynomial degree. However, considering we have a data set of more than 24.000 values, the 8 parameters of the 6th order polynomial are comparatively very few (and not certainly able to fit anything).
Line 347. Do the authors mean radial pattern?
REPLY – yes, we do.
Line 371. Should geometrically read geometric?
REPLY – yes, it is.
Figure 9. The polynomial curve is indistinct. Could the authors use a different colour like yellow or something to increase the contrast?
REPLY – ok, we did so.
Lines 375 to 376. Is there any reason that r and N are in quotation marks?
REPLY – No, we removed the quotation marks.
On a general point, the authors’ sentences are rather long, sometimes circa 60 words. It would be helpful, it seems to this reviewer, if the authors could be more succinct.
REPLY – The text has been revised to be more concise.
Notwithstanding my aforementioned comments this is a good paper that would benefit in particular from attention to lines 237-238 in particular.
REPLY – thanks for the very useful comments; as we explained, there was a misunderstanding on the standard deviation value: it only reflects the large range of values in the data set.
I trust the authors find these comments helpful and constructive.
REPLY – yes, thank you again.
Comments on the Quality of English Language
The English was a little longwinded with some sentences @ 60 words. I would respectfully encourage authors to be succinct and get to the point. It might commend their papers to a wider readership.
REPLY – The text has been completely revised to be more concise.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article presents two major issues. The first is that it is based on a geological model that does not match the field evidence (the boundary of the YNT is farther north). The second is that a 100 mm difference between the model and actual data seems too high, considering the contrast being analyzed. The model needs to be refined further to reduce these discrepancies.
Comments for author File: 
Comments.pdf
some mistakes were detected
Author Response
Comments and Suggestions for Authors
The article presents two major issues.
The first is that it is based on a geological model that does not match the field evidence (the boundary of the YNT is farther north).
REPLY – Yes, there was a mistake in the NYT North border, we have corrected in the revised version. Recent papers have shown the caldera has been formed uniquely by the NYT eruption (Rolandi et al., 2020a; 2020b; de Natale et al., 2022;2024), by re-defining its borders; we wrongly used the NYT borders from the old hypotheses.
The second is that a 100 mm difference between the model and actual data seems too high, considering the contrast being analyzed.
REPLY – The rather large RMS between the data and the radial model just reflects the existence of a second order, non-radial pattern. So, it is exactly linked to the main result of this paper. 10 cm, over a maximum uplift of about 1.4 meters, is not so large to hide the basically radial character of the deformation pattern, but still significant to put in evidence a second order, non-radial pattern, linked as we show to the main structural features of the area.
The model needs to be refined further to reduce these discrepancies.
REPLY – See previous reply.
Comments on the Quality of English Language
some mistakes were detected
REPLY – The mistakes were corrected.
Annotations on pdf
Line 34 - reference please
REPLY – Yes, we added it.
Lines 45-46 - please rewrite this sentence. It is poor clear
REPLY – Ok, the sentence has been rewritten.
Lines 76-77 - please rewrite
REPLY – Ok, the sentence has been rewritten
Line 78 – an
REPLY – Ok, corrected.
Line 80 - has
REPLY – corrected
Line 87 – only very
REPLY – corrected
Line 108 - and it is
REPLY – corrected
Lines 112-114 - Reference 33 must be deleted because it is not still accepted. May be interesting comparing this model with the previous model largely recognized (es Rosi et al.).
REPLY – reference 33 is now in press. We mention in the introduction also the old models (i.e. Rosi et al., 1996).
Lines 117-120 - This image does not consider all the strong evidence of the CF caldera in the northern sector. Please revise all the related papers as Rosi, Isaia etc
REPLY – Ok, we have corrected the figure, which was actually wrong for our mistake.
Lines 134-136 - see the previous comment
REPLY – The sentence has been rewritten.
Line 272 – reference
REPLY – No reference is needed. We have obtained the measured values by Sentinel-1 interferometric data processing.
Lines 383-384 - a 10 centimeter difference between simulated and real measurement is high!
Lines 389-390 - it is so high this difference in deformation values
REPLY – The rather large RMS between the data and the radial model just reflects the existence of a second order, non-radial pattern. So, it is exactly linked to the main result of this paper. 10 cm, over a maximum uplift of about 1.4 meters, is not so large to hide the basically radial character of the deformation pattern, but still significant to put in evidence a second order, non-radial pattern, linked as we show to the main structural features of the area.
Line 416 – values
REPLY – corrected
Lines 439-440 - I think the author must be more impartial when present the data
REPLY – Ok, we modified the sentences.
Lines 683-684 - I think that a submitted paper can not be accepted in the reference because is not still accepted
REPLY – the paper is now in press.
Reviewer 3 Report
Comments and Suggestions for AuthorsI have several doubts about the relevance of the study.
After reviewing the manuscript “A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in active volcanic caldera” the authors present a simple model to evaluate the deformation caused by magma movement (possibly) in the Campi Flegrei caldera. The authors use both satellite and gps data to model and validate their results.
Although the title explains the objective of the manuscript, this title tends to be misleading as it does not clearly indicate that the model has been developed exclusively at Campi Flegrei and has not been used at other volcanoes or in other time series yet. I consider that a reference to Campi Flegrei should be clearly added in the title to solve this misleading problem.
The introduction and study area sections should be revised. In the way that the ideas are presented and arranged, it is not clear to me what the research problem is, or what the authors' motivations are for developing this numerical model to evaluate deformation. Without this critical step, it is not clear whether the conclusions are in line with the objective and whether they contribute to solving the research problem.
The numerical model requires better supporting arguments. E.g., I consider that raising the degree of the polynomial equation to 6 is not well supported. According to the manuscript, this change is based on the reduction of the R2, although the fit is already quite adequate with degree 3 or 4.
Moreover, the authors compare the results between GPS and InSAR data. However, they do not clarify which is the method/equation for the uncertainty calculation. Without this calculation, it is not clear whether the level of fit between both data sources is relevant or not, i.e., whether it is within the uncertainty value or not.
The discussion and conclusions sections of the manuscript need to be rethought. The manuscript is heavily focused on the authors' observations and perspectives, with a low level of comparison of their findings with those of other authors. Campi Fegrei is a highly studied system, including its deformation. So, what is the utility of proposing a simple model to understand the deformation? what advantage does this model have over more complex/complete models proposed by other authors? how do the results of this model compare with the observations of other authors? it would be valuable to do a short exercise with the data of another volcano with GPS data already published.A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in active volcanic caldera. In this sense the discussion section and its conclusions should be carried out, which should be in accordance with the research problem identified in the introduction section.
English should also be reviewed. I find some grammatical errors in the text. This topic can be revised once the problems described above have been solved.
Comments for author File: Comments.pdf
Author Response
Comments and Suggestions for Authors
I have several doubts about the relevance of the study.
REPLY – the revised manuscript more clearly describes the methodologies and aims of our research and the results obtained; we hope this will be helpful in overcoming the doubts that arose from reading the first version of the manuscript
After reviewing the manuscript “A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in active volcanic caldera” the authors present a simple model to evaluate the deformation caused by magma movement (possibly) in the Campi Flegrei caldera. The authors use both satellite and gps data to model and validate their results.
Although the title explains the objective of the manuscript, this title tends to be misleading as it does not clearly indicate that the model has been developed exclusively at Campi Flegrei and has not been used at other volcanoes or in other time series yet. I consider that a reference to Campi Flegrei should be clearly added in the title to solve this misleading problem.
REPLY – The title has been changed accordingly. Now the paper is mostly focused on Campi Flegrei unrest (although the method is useful for any other caldera showing mostly radial or elliptical deformation), and the goals and results of the paper are clearly stated.
The introduction and study area sections should be revised. In the way that the ideas are presented and arranged, it is not clear to me what the research problem is, or what the authors' motivations are for developing this numerical model to evaluate deformation. Without this critical step, it is not clear whether the conclusions are in line with the objective and whether they contribute to solving the research problem.
REPLY – The introduction section has been revised to better explain the research goals and the motivation for developing the numerical model to evaluate deformation. The study area section has been improved.
The numerical model requires better supporting arguments. E.g., I consider that raising the degree of the polynomial equation to 6 is not well supported. According to the manuscript, this change is based on the reduction of the R2, although the fit is already quite adequate with degree 3 or 4.
REPLY - We have used a criterion based on the RMSE values, as explained in the paper, to select the best polynomial degree.
Moreover, the authors compare the results between GPS and InSAR data. However, they do not clarify which is the method/equation for the uncertainty calculation. Without this calculation, it is not clear whether the level of fit between both data sources is relevant or not, i.e., whether it is within the uncertainty value or not.
REPLY – The measurement uncertainty values of GPS and InSAR data, stated by the respective authors, have been already reported in methods and discussion sections. We have described the R2 and RMSE values for each equation of the processed polynomial curves, representative of the model uncertainty. All reported uncertainty values are small and do not affect the results of the performed study.
The discussion and conclusions sections of the manuscript need to be rethought. The manuscript is heavily focused on the authors' observations and perspectives, with a low level of comparison of their findings with those of other authors. Campi Flegrei is a highly studied system, including its deformation. So, what is the utility of proposing a simple model to understand the deformation? what advantage does this model have over more complex/complete models proposed by other authors? how do the results of this model compare with the observations of other authors? it would be valuable to do a short exercise with the data of another volcano with GPS data already published.
A procedure for monitoring vertical ground deformation anomalies using MT-InSAR data during unrest phases in active volcanic caldera. In this sense the discussion section and its conclusions should be carried out, which should be in accordance with the research problem identified in the introduction section.
REPLY – The reason why it is useful to define and preferable to use simpler models over more complex models is generally obvious: in scientific research a simple, replicable model is preferable to a complex model that provides comparable results (Occam’s razor). But our paper wants to explore the systematic, second order feature of the vertical deformation fields, beyond the first order radial shape, which hide further details. In such a way, we have been able to retrieve precious information about the main seismotectonic structures of the caldera, clearly associated to the most important seismicity. The discussion and conclusions sections have however been improved accordingly.
Comments on the Quality of English Language
English should also be reviewed. I find some grammatical errors in the text. This topic can be revised once the problems described above have been solved.
REPLY – The grammatical errors were corrected.
Annotations on pdf
Line 2 - new (?)
Line 2 - monitoring
Line 2 - I don't think it's a monitoring method per se, it's just a model for analyzing deformation with multiple centroids of uplift. This model does not provide the complete tools for monitoring a volcano, following what is described in the manuscript.
Line 3-4 – active volcanic
Line 4 - Campi Flegrei
Line 4 - As the model was developed/applied in Campi Flegrei, and the discussion of the applicability of the model in other caldera systems (explosive or drainage) has not been analyzed/presented, it is imperative to mention Campi Flegrei in the title.
REPLY – The title has been changed accordingly.
Line 12 - detecting the detection of
Line 13 - s
Line 14 - helping aiding
Line 16 – To For
Line 17 - aim purpose
Line 17 - have
Line 17 - the
Line 18 – they that they
Line 18 - only only on
Line 19 - the
Line 19 - the
Line 21 – represents is
Line 22 – , i.e.,
Line 23 – to analyze the
Line 23 – the
Line 23 – ,
Line 24 – Coeval GPS
Line 25 – results
Line 25 – show
Line 25 – pronounced
REPLY – all corrected
Line 25 – orientation (?)
REPLY – alignment is better in our opinion
Line 26 - offer
Line 27 – investigations
Line 27 – provide a
Line 27 – improving
REPLY – all corrected
Line 32 – The introduction section needs to be restructured. The ideas need to be chained together. I understand that deformation in volcanic calderas is common, and Campi Flegrei is a good example. But, as it is a common volcanic phenomenon, there are numerous examples in the literature on techniques to detect, evaluate, model and interpret deformation in volcanic calderas (explosive calderas like camp fleg and drainage calderas like galapagos). So, why is it necessary to propose a new model? What is the differentiating element in the model of this manuscript? Is the model applicable in other contexts?
Line 76 - OK, I understand the whole background about cortical deformation processes generated by shallow magma intrusions in volcanic calderas. But I do not understand what is the aim of the manuscript, what is the research question to be solved, and what are the authors' perspectives on it.
REPLY – We have better described the aim of the paper and the research problem to be solved.
Line 77 - Which came first, the development of the model using training data from an external database and then applied to Cam Flegrei, or the development of the model using the Cam Flegrei data, or was a previous methodology improved by applying the Cam Flegrei data? This should be better outlined in the manuscript, including its title.
REPLY – We focused the paper about the Campi Flegrei case study. However, the procedure can be applied to any other area in which a mainly radial or elliptical deformation pattern may hide important second order details linked to tectonic structures. We have changed title abstract and introduction section to better outline this approach.
Line 87 - This is interesting, I recommend focusing also on this topic in the discussion section.
REPLY – We have focused on it in conclusion section.
Line 105 - I think that this paragraph should go before, in order to better introduce the problem to be studied.
REPLY – We have better clarified the problem to be studied.
Line 106 - Ok. I understand that the eruptive history of the caldera, with several eruptions even up to the 16th century, is very dynamic and extensive, with multiple episodes of inflation and deformation. I understand that the deformation at Cap Fleg is highly dynamic and extensive, with multiple episodes of inflation and deformation. But what is the real contribution of this section to the study problem? How does this section introduce a fundamental concept in the manuscript? To solve this, it is necessary to rephrase the introductory section. Why was Cam Fleg chosen? Because of its long eruptive history? Because it has had recent major eruptions? or because the data are more robust because of the degree of deformation? because it has large deformation rates? These questions would provide a better understanding of the chain of ideas that are being presented.
REPLY – Campi Flegrei are one of the highest volcanic risk regions in the world, with a long eruptive history and is currently experiencing a seismically active unrest phase. This is the reason for which this area has been chosen for this study. Now we have been more clear to point out the focus of the work and the main problems we want to solve.
Line 152 - phreato-magmatic eruption
REPLY – corrected
Line 152 - Seismicity should be mentioned first because it is the most commonly recorded before soil dimorphism.
Line 163 - You should mention first the recorded seismicity. An unrest episode in a volcano is commonly marked by well recorded seismic swarms that are possibly followed by ground deformation.
REPLY – We prefer to do not change the order; ground deformation at Campi Flegrei, however, normally starts well before than seismicity.
Line 160 - Very short idea to make a paragraph for just one sentence. Join it with the previous paragraph.
REPLY – corrected
Line 175-176 - Check that all geographical names appear in the corresponding figure. Fig 1 in this case. Apply it for the whole manuscript.
REPLY – We checked the geographical names that appear in the figures and text.
Line 177 - idem. Where is the RITE station located?
Line 178 - No! References to later tables or texts should be avoided. Better mark it in Fig 1
REPLY – RITE station location has been added in Fig. 1
Line 206 - As said, the methodology shows the existence of multiple methods to evaluate ground deformation. But it does not justify why it was decided to create a new model.
REPLY – We don’t understand well this question. It is well known since 70’s years that the pattern of ground uplift (and subsidence) at Campi Flegrei is markedly radial: this is an observation, not a model. In this paper, we want in fact to discover if the deformation pattern also contains, hidden by such an apparent first order shape, second order details linked to the main seismotectonic structures in the area. And, finally, our results confirm that uplift data contains crucial information on such structures.
Line 245 - How is this deformation center determined?
REPLY – The deformation center has been determined by several authors in literature [61,82,99,100] as we have written in line 243.
Line 255 - I am not sure about this. What is the justification for increasing the polynomial degree to 6? the fit is sufficiently adequate at 3rd degree, maybe 4th. R2 gains only 0.002 passing from 4th to 6th degree. I can find no substantive justification for it.
REPLY – We have used a criterion based on the RMSE values, as explained now better in the revised version of the paper, to select the best polynomial degree.
Line 256 - You can place the caption inside the figure to save space. enlarge font size
Line 257 - It is not clear what z and r mean without first reading the text. That makes the figure confusing. Put directly “Distance to deformation center (r)” and "vertical uplift value in the EGMS Ortho Vertical dataset (z)"
Line 257 - And where is the data in the figure? For the reader, curves 3-6 are very similar, so it makes no sense to increase their degree. Unless, it is observed that the data set (which is not placed in the figure) actually fits the 6th degree curve better. If the data set is very sparse, as in Figure 9, there is no justification for increasing the degree of the equation.
REPLY – ok done. Figure changed
Line 283 - idem. A very short sentence
REPLY – corrected
Line 315 - idem. What is the justification for increasing the degree of the equation to 6?
REPLY – see previous reply to line 255
Line 317 - idem. How is this deformation center determined?
REPLY – see previous reply to line 245
Line 320 - A text about the uncertainty range in the modeling is missing here. For the data set used to create these curves, what is the confidence interval? what equation represents this uncertainty? is the uncertainty significantly reduced between a grade 4 and a grade 6, for example?
REPLY – We have rewritten and improved this section.
Line 370 - This is important. There are better known modeling approaches that do use volcano-tectonic models from the simple to the complex.
REPLY – ok
Line 382 - Are these values within the confidence interval of the modeling equations used?
REPLY – these was already discussed in lines 550-553
Line 424 - the lineaments, and even more the faults, are not totally straight lines as marked on the map. What is the source and the criteria used to draw the lineaments? Additionally, to which of all the black lines do A, B and C refer. Explain clearly what these letters are pointing to.
REPLY – The straight line on the map are the volcano-tectonic faults and lineaments by Natale et al. [52], as reported in the caption of Fig. 1 when they are showed for the first time in this paper. A, B and C do not refer to specific single black line, but they are the borders among the area with different vertical residual values, showed with different colors as indicated in the map legend. We have added these inferred lineaments in Fig. 10.
Line 446 - what do the axes mean? where are the captions? What are the units of measurement of the axes?
REPLY – the figure has been corrected
Line 448 - idem. AXES. The texts are impossible to read. They are at low resolution and with a font size that is unreadable.
REPLY – the figure has been corrected
Line 451 - I do not find a substantive discussion that interprets the results obtained. What is the advantage of this proposed model? with what variables does the model stop working? how does this model compare with other simple or complex models available in the literature? how does the model compare with others already done at Camp Fleg? What are the prospects for the continuity of the project?
REPLY – Discussion has been improved, now we believe the goals and the results of our study are well clear and very significant.
Line 480 - this is something that was already known and thus confirmed
REPLY – ok
Line 494 - So what is the real contribution of the proposed model? What is the advantage of using its equations instead of using one of the known source models available in the literature?
REPLY – this is a key point: we don’t know exactly the details of the model generating the deformation (there are many and substantially contrasting models, from purely magmatic to purely hydrothermal, with several shapes, etc.), so that we simply want to find an analytical model best fitting the first order, radial pattern of uplift. This is actually the most reasonable way to proceed, just because we are not interested to interpret the radial pattern, but just to eliminate it from the signal in order to explore the residual uplift. And we show in the paper it was a very successful procedure, enabling us to put in evidence important structural details.
Line 563 - The discussion section needs to be redesigned. It is important to note to compare the model with others in the literature. Explain clearly the advantages of this equation. In the same vein, compare the application of this model with an additional case study. and the risk? The introduction discusses the risk associated with uplift and subsidence in the area. So, I don't see a significant contribution in this area either.
REPLY – As discussed before, the aim of the paper was not to interpret the first order, radial deformation (and hence compare a purely geometric equation with other volcanological models), but, on the contrary, to eliminate the radial pattern to interpret residual deformation.
Line 567 - since they only made the model in Camp Fleg, then, they cannot leave the name too general, because it generates misleading expectations in the reader.
REPLY – Ok, we changed the title and explained better.
Line 598 - The conclusions are highly focused on the authors' perceptions. There is no comparison between what the authors found and what was observed in other studies for the same volcano. Worse, there is no comparison with studies and observations at other volcanoes around the world. This raises doubts about the applicability of the model and therefore the relevance of the study.
REPLY – Conclusion has been clarified, but the reply on this point is the same already explained at previous points.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe text is ready to be accepted in this form
Author Response
Many thanks to the reviewer for her/his very useful comments
