Dual-Link Synchronous Acquisition and Transmission System for Cabled Seafloor Earthquake Observatory

Round 1

Reviewer 1 Report

This article is devoted to the development of a data acquisition and transmission system that is potentially applicable for cabled seafloor networks of seismic stations. This topic is very relevant for the development of such systems necessary for the operational monitoring of potential catastrophic events associated with marine seismic activity.

Despite the detailed description of some technical solutions, in the opinion of the reviewer, the presented text is not enough for publication in the form of a full-fledged research article.

For example, in the Discussion section, a detailed analysis of the results, advantages and disadvantages, comparison with other similar works, etc. is usually presented. In its present form in the manuscript, the Discussion section is quite small, and statements about the stability, high performance and efficiency of the presented technical solutions in comparison with analogues remain unfounded. There is no Conclusion section at all. Some figures, for example, No. 2, 4, 8 are uninformative. Instead, drawings demonstrating an analysis of the efficiency, performance and stability of the system would be appropriate.

There are also many spelling incorrectnesses in the text. For example, somewhere it says "NEPTUNE", and somewhere "NEPTURE".  Somewhere it says " Zynq7000 Soc ", and somewhere " Zynq7000 SoC ".  It must be harmonized.

It is recommended also to describe how the system works in case of external time synchronization long failure. Is thermostatted crystal oscillator used and what is its temperature stability? What happens if the SD card is full in the event of a long transmission failure? Cyclic overwrite?

I recommend a major revision of the article.

Author Response

Point 1: For example, in the Discussion section, a detailed analysis of the results, advantages and disadvantages, comparison with other similar works, etc. is usually presented. In its present form in the manuscript, the Discussion section is quite small, and statements about the stability, high performance and efficiency of the presented technical solutions in comparison with analogues remain unfounded. There is no Conclusion section at all.

 Response 1: Thanks for your comments. We have adjusted and expanded the structure and content of section 3 and section 4 in response to your comments.

As for the stability, high performance and efficiency of the system, it is reflected that we upgrade the system from the original single-link transmission to dual-link transmission, when one of the links fails, the other link can still operate independently and normally, at the same time, if the failure occurs as a transmission failure, then the node will continue to work and store its own node data in the SD card, which means that the data will be stored in the SD card within a certain period of time between the researchers' observation of the failure and the resolution of the failure, instead of complete loss of data, which can improve the stability of the system. We also have explained it in the section 3.2.1 -- “After running duplex SQATS for a long time, no data bit loss or packet loss is observed, proving the stability of duplex SQATS.”

Point 2: Some figures, for example, No. 2, 4, 8 are uninformative. Instead, drawings demonstrating an analysis of the efficiency, performance and stability of the system would be appropriate.

Response 2: Thanks for your comments, I have removed figure No.2, as for figure No.4, the reason I put it in the article is to prove that we have a user-friendly link management system to manage the link transmission data. And figure No.8 is an excerpt of the data stored on the SD card after each node has been working normally for some time. After modification, the data stored on the SD card conforms to the previously set frame format and the data is valid as can be seen from the figure. Also due to the different storage mechanisms, there is a slight difference between the end nodes and intermediate node storing data, which is illustrated in the image and therefore needs to be preserved.

Point 3: There are also many spelling incorrectnesses in the text. For example, somewhere it says "NEPTUNE", and somewhere "NEPTURE".  Somewhere it says " Zynq7000 Soc ", and somewhere " Zynq7000 SoC ".  It must be harmonized.

Response 3: Thank you. We have revised them.

Point 4: It is recommended also to describe how the system works in case of external time synchronization long failure. Is thermostatted crystal oscillator used and what is its temperature stability?

Response 4: In the event of external time synchronization failure, the P88 1588 PTP will enable its own TCXO hold time with time accuracy of up to 1.5μs over 8-30 minutes.

Point 5: What happens if the SD card is full in the event of a long transmission failure? Cyclic overwrite?

Response 5: When the SD card is full, the data will overwrite the earliest data, that is to say, taking the node 1 SD card as an example, a full SD card always stores the data collected in the time period from the current moment to 159 days ago. If you need to ensure that the data is not lost at all, the relevant researchers only need to troubleshoot the problem within 159 days after the failure.

Reviewer 2 Report

The paper proposed a hardware system developed to improve SQATS system in order to provide long-term and real-time monitoring of seafloor seismic activities along East China Sea. Developing such technology is very important for societal and economical activities. Overall the paper is well written except the discussion which I found very short. I have two comments,

- *     Is it possible to show some seismic waveforms recorded by the seismometers?

-  *  I propose to add the following sentence or similar to it in order to enrich the discussion section and show how the technology is implicated in the understanding and monitoring of seismic hazards, “ Applying some techniques on the observed data, such as full waveform inversion (e.g. Takougang et al., 2020) to derive some physical parameters namely velocity and  seismic attenuation (e.g. Bouchaala et al., 2021; Del Pezzoet al., 2019 ). Such parameters are used for qualitative and sometimes quantitative estimate of subsurface properties  such as faulting orientation and location, fluid content and stress distribution (Trugman et al., 2020)”

-        -   Bouchaala, F., Ali, M.Y. and Matsushima, J., 2021. Compressional and shear wave attenuations from walkway VSP and sonic data in an offshore Abu Dhabi oilfield. Comptes Rendus. Géoscience, 353(1), pp.337-354.

-          - Del Pezzo, E., Giampiccolo, E., Tuvè, T., Di Grazia, G., Gresta, S. and Ibàñez, J.M., 2019. Study of the regional pattern of intrinsic and scattering seismic attenuation in Eastern Sicily (Italy) from local earthquakes. Geophysical Journal International, 218(2), pp.1456-1468.

-         - Takougang, E.M.T., Ali, M.Y., Bouzidi, Y., Bouchaala, F., Sultan, A.A. and Mohamed, A.I., 2020. Characterization of a carbonate reservoir using elastic full‐waveform inversion of vertical seismic profile data. Geophysical Prospecting, 68(6), pp.1944-1957.

-       -   Trugman, D.T., Ross, Z.E. and Johnson, P.A., 2020. Imaging stress and faulting complexity through earthquake waveform similarity. Geophysical Research Letters, 47(1), p.e2019GL085888.

Small editorial corrections are added in the attached file.

 

Regards

Comments for author File: Comments.pdf

Minor editing is required

Author Response

Point 1: Overall the paper is well written except the discussion which I found very short.

Response 1: Thank you for your comments. We have revised the relevant section according to your suggestion.

Point 2: Is it possible to show some seismic waveforms recorded by the seismometers?

Response 2: We are sorry that we are unable to provide seismic data waveforms in this article for the time being because the project is a joint effort with other organizations and we need the shell design department to complete a watertight shell before we can conduct underwater seismic data acquisition experiments. In addition, the further development of the experiment is subject to the availability of related funding. When all the above objective conditions are met, we will start the underwater seismic data monitoring experiment.

Point 3: I propose to add the following sentence or similar to it in order to enrich the discussion section and show how the technology is implicated in the understanding and monitoring of seismic hazards, “ Applying some techniques on the observed data, such as full waveform inversion (e.g. Takougang et al., 2020) to derive some physical parameters namely velocity and  seismic attenuation (e.g. Bouchaala et al., 2021; Del Pezzoet al., 2019 ). Such parameters are used for qualitative and sometimes quantitative estimate of subsurface properties  such as faulting orientation and location, fluid content and stress distribution (Trugman et al., 2020)”

 Response 3: Thanks for your suggestion. As mentioned in response 2, we will conduct underwater seismic data monitoring in our next experiments, and the reference paper you provided is a very significant guide for our next experiments.

 Point 4:  Small editorial corrections are added in the attached file.

Response 4:  Thanks for your suggestion. We have revised them.

Round 2

Reviewer 1 Report

Now the article is perceived better. The novelty of the technical solution and its strengths have become more transparent.

However, some sloppiness in the text is still present.

For example, in the captions to figures 3,4,5,7 there are no spaces, dots at the end of the sentence, capital letters at the beginning of the sentence.

Line 355 also has a missing space.

In conclusion in line 343 tautology «improvements improve».

Careful text editing is recommended.

Author Response

Point 1: For example, in the captions to figures 3,4,5,7 there are no spaces, dots at the end of the sentence, capital letters at the beginning of the sentence.

Response 1: Thanks for your comments. We have revised them.

 

Point 2: Line 355 also has a missing space.

Response 2: Thank you. We have revised it.

 

Point 3: In conclusion in line 343 tautology «improvements improve»

Response 3: Thank you. We have changed the expression of the sentence.

“These enhancements lead to an increase in the system's fault tolerance on link data transmission, and greatly promote the reliability and robustness of the original system.”

 

Point 4: Careful text editing is recommended.

Response 4: Thank you. We have also revised some other text errors.