The Urban Seismic Observatory of Catania (Italy): A Real-Time Seismic Monitoring at Urban Scale

Round 1

Reviewer 1 Report

Dear Authors,

I have thoroughly read your paper titled „The Mw 4.3 Catania Plain earthquake of December 23, 2021 recorded at the Urban Seismic Observatory of Catania (Italy)” submitted for consideration for publication to Remote Sensing, MDPI.

This article deals with the urban seismic observatory network OSU-CT, which is used for seismic hazard monitoring. In particular, the authors focus on presenting the technical aspects of this type of observatory network and show how urban seismic monitoring and urban mapping of the intensity of ground shaking can mark an important milestone toward the evaluation of how environmental threats affect the built heritage on the example on Italy (vicinity of Mount Etna district).

In general, the article is well structured, and the research results obtained are supported by the analyses conducted and the description of the methodology as well. The article is written in good English, also the quality of graphics - in most cases - is satisfactory. However, I propose to include two minor comments, namely:

1) Add mesh grid to Figure 2, add information about coordinate system;

2) Redraw Figure 4 to show the exact location of stations on a horizontal plane (standard map, not Google Earth screen).

After introducing these minor remarks, the article could be published in Remote Sensing.

Kind regards,

Reviewer

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

1. The paper is mainly about the sensing system, but the title is the name of the earthquake. Suggest to revise the title of the paper to fit with its contents.
2. Writing style of this draft is more like a report than an technical paper. By realizing the important of the urbun monitoring seismic system, certain issue such as sensing problem, data transportation problem, that authors would like to discuss should be clarified. Construction and maintenance cost was the biggest issue for those scale of sensing network, how to using low cost new technology should be explained. Also the literature should be explained as well. Chapter 2 explained those very well, please consider to combine them and explain those earlier.
3. What is the main purpose of this OSU-CT? How can this be contribute for disaster mitigation is unknown. We can find this is an earthquake prone area. Seismic record can help to find how great the shake it is. Authors mentioned some keyword such as EEW and post-earthquake rapid disaster assessment. But those are not include in the work of this paper. It is quite a question that a net work geometrically concentrated in a small area can provide meaningful EEW in future. And there is no much information about post-earthquake rapid disaster assessment has been explained here.
4.   The acc and vel seems have low resolutions. There is very few comments lower than 1 Hz. What is the reason. ADXL 355 is carrying low cut filters. Did the system settled those filters? Please clarify the filters setting.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for your work!
It's quite good, but it can be a little better. The main drawback is a lack of figure 13. Also, have you made a velocity-frequency diagram, such as the one on this paper?
https://www.geosig.com/files//GS_AC-63_Leaflet_V09.pdf

Some small English mistakes:

line 12, missed comma: vulnerability, and earthquake

line 40:  has been estimated as at least three billion euros per year

line 47: are rapidly assessed

line 60, missed comma: Building-scale monitoring networks, on the other hand,

line 71: hazards

line 109: progress.. has opened

line 112: in the case

line 154, comma: Messina, and other

line 157: Sicily's historical and instrumental seismicity

line 164: 1848, and 1990

line 188: without adequate

line 191: the city was at the center of intense research activity both at the national and European level

line 215: the real-time data ensures

line 240: these IP addresses

line 287: The output 

line 406: This section, provides

line 438: 28 kilometers

line 465: Enna, and Messina,

line 477: the map of the intensity

line 518: between the two farthest stations 

line 598: the different responses

line 620: squre root sign missed and "this last presents"

line 658: Also, the study

line 661:  with increasing levels

line 671: factories, and so on

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Thank you for your work!

Author Response

Dear reviewer,

we would like to thank you for reading our work and for the suggestions you gave us to improve it. 

Best regards,

Giuseppina Tusa and Co-authors