This is a quite interesting paper which focuses on the comparison of geodetic and seismic moment rates across Europe. The approach is successful in spite of the large area examined and its high seismotectonic heterogeneity. 

A major issue which needs revision is the organization of the paper. In lines 61-64 the authors claim that “In a first step, we present the datasets and methods used to compute the seismic and geodetic moments integrated in space and time and to explore the uncertainties. Next, we compare the estimated seismic and geodetic moments in the different seismogenic source zones of ESHM20 that covers the Euro-Mediteranean region. We then discuss the parameters that influence the most the compatibility in both high and low-to moderate seismic activity.” However, the overall structure of the paper is inconsistent with the claim. Namely, there is a main section “1. Introduction” and all the material of the paper is presented within this section with sub-sections numbers ranging from 1.1 to 1.5. Section 1 is followed by section “2. Conclusions”. 

I recommend the drastic reorganization of the paper’s structure in a way that makes clear the “real” Introduction, which should be followed by an appropriate number of sections, possibly four, devoted to “Methods and Data”, “Results”, “Discussion”, and “Conclusions”. 

Other comments. 

 47-49. “In the Hellenic arc, Jenny et al. (2004), found that the maximum magnitudes required for the earthquake recurrence models to be moment-balanced were unrealistic and concluded that a large part of the strain is released in aseismic processes”. However, this fundamental result has been supported by previous authors, including Papadopoulos (1989) and Becker & Meier (2010). 

227-228. “If earthquake catalogs of much longer time windows were available (e.g. 100,000 years), would the spatial distribution of the seismic moment rates be more alike the spatial distribution of the geodetic moment rates?” This critical question is not replied. Do the authors have a reply to that?

305. The last glacial maximum should be ~20,000 years. 

In Figure 2, the black polygons representing area sources in most cases are not recognizable. Is it possible to improve its? Similarly, Figure 7 and subsequent figures need improvement.

References

Becker, D. Meier, Th., 2010. Seismic Slip Deficit in the Southwestern Forearc of the Hellenic Subduction Zone. Bulletin of the Seismological Society of America, 100 (1): 325–342. doi: https://doi.org/10.1785/0120090156

Papadopoulos, G.A., 1989. Seismic and volcanic activities and aseismic movements as plate motion components in the Aegean area, Tectonophysics, Volume 167, Issue 1, Pages 31-39, https://doi.org/10.1016/0040-1951(89)90292-8.

My feedback on the manuscript is included in the attached PDF file.

The study is well-organized and clear. To complete it I suggest inserting some quotes in the introductory part:

Nakamura, M., Kinjo, A. Activated seismicity by strain rate change in the Yaeyama region, south Ryukyu. Earth Planets Space 70, 154 (2018). 

Pappachen, J. et al (2021). Crustal velocity and interseismic strain-rate in the Garhwal–Kumaun Himalaya. Scientific reports, 11(1), 1-13.

Zeng, Y. et al (2018). Earthquake potential in California-Nevada implied by correlation of strain rate and seismicity. Geophysical Research Letters, 45.

In the paragraph 1.4 Focus in Italy, please produce a comparative and critical analysis with the following previous studies, focussing on the difference of the applied methods and the conclusion:

Riguzzi, et al (2012). Geodetic strain rate and earthquake size: new clues for seismic hazard studies. Physics of the Earth and Planetary Interiors, 206.

Farolfi, G., et al (2020). Spatial forecasting of seismicity provided from earth observation by space satellite technology. Scientific reports, 10(1), 1-7.

Piombino, A. et al  (2021). Assessing current seismic hazards in Irpinia forty years after the 1980 earthquake: Merging historical seismicity and satellite data about recent ground movements. Geosciences, 11(4), 168.

Once these minor changes have been made, the article can be published.

The paper deals with the contribution of geodetic monitoring to the probabilistic hazard assessment, by enhancement of the source model. The subject is fascinating and worth to be published. There are, however, certain points in the manuscript that need additional work and corrections. Specific comments are reported, which I hope will contribute to improving its revised version.

MAJOR COMMENTS

1. Line 173: Is it only the thickness or exactly the boundaries (upper and lower depth) of the seismogenic layer? This statement demands more elaboration.
2. Line 175: There are plenty of publications related to your study area where you may take this information. Highly accurate relocated data provide a consistent definition of the seismogenic layer. It seems that you have not taken into account these outcomes from Greece.
3. Line 199: This complies with my comment to take as much precisely as possible the seismogenic layer. These data exist in numerous publications and my suggestion is to take them into account in your calculations.
4. Please, provide the outcomes from the fast deforming areas, alike Greece and western Turkey.
5. Line 213: How are you evaluating the largest possible earthquake in each source? This is a very delicate issue and must be considered with caution. Even in areas with a wealth of historical data, like in Aegean, the definition of Mmax demands much elaboration.
6. Line 216: Fie how many faults have you got documented traces? They are very rare for earthquakes of m~6.0 or smaller. You must support this input for each fault segment.
7. Line 216: How do you know the extension in depth? This is based on highly accurate relocated seismicity, but this component is missing in your work.
8. Lines 228 – 229: Why don’t you use synthetic catalogs to reply to this question?
9. Line 267: What is the interpretation for this?
10. Line 282: It is not the b–value but the a–value of the G–R law that expresses the level of seismic activity and the areal size. Please, comment on that and explain how you have adjusted the a–values and what the result has been.
11. Line 285: Could you be more specific about “unusual”? Besides, there are plenty of publications addressing the non–linearity of G–R relation in its entire range.
12. Line 308: These are defined by seismicity, faulting, and related physical properties. Have you used geodetic measurements alone to define seismogenic sources?
13. Lines 310–312: “… at least 30 events …” – small? Large? How have you selected these 30 events?
14. Line 399: is it only the number of earthquakes that matters or their magnitude (their moment respectively)?
15. Line 402: Could you be more specific? How much “high” and how “episodic”?
16. First paragraph of Conclusions section: It is rather a summary – please take it out if this section.
17. The last part of conclusions is rather “Discussion” than “Conclusions” – please provide explicitly the conclusions of the study.
18. SPECIFIC COMMENTS
19. Section 1.2.2: It is better to put the calculation technique in an appendix.
20. Line 178: In almost “inactive” areas have you considered crustal thickness from ambient noise tomography? Please, clarify. Caution: crustal thickness is not identical with seismogenic thickness.
21. Line 190: Could you, please, support why didn’t you consider an area in Greece with high seismic activity? For the sake of comparison among areas with different strain rates.
22. Line 209: What do you mean by that term and how are you estimating it?
23. Lines 217–219: Lack of clarity, please rewrite this text.
24. Lines 221–224: this introductory part needs more elaboration.
25. Line 254: what do you mean by that? Could you be more specific?
26. Line 255: Consistent on what? Could you be more specific?
27. Line 261: Is the size of the source zone that matters or the deformation intensity?
28. Line 262: Could you please explain briefly what are they and how are they defined?
29. Lines 349 – 351: Of course it does.
30. Three first paragraphs of page 25: many repetitions – for the reader’s sake please, reorganize the text.