I believe that some major revisions are required to make this acceptable, so please implement the changes outlined in your responses to the referees and then I would like the referees to review it again.

Referee 1 now recommends acceptance while Referee 2 continues to have some concerns. I have gone through the comments of Referee 2 and agree that some additional revision would make the paper stronger, and so I invite you to submit a revised version.

Please note that the page and line numbers cited by Referee 2 are based on the version
nhess-2019-285-author_response-version1.pdf
and not on the resubmitted manuscript
nhess-2019-285-manuscript-version4.pdf
But as far as I can tell, the text in the resubmitted manuscript agrees with the green text in the author response version, so the comments still apply.

I agree with most of the suggestions to further clarify the discussion or the figures and I think these would mostly require only minor modification to the text. Also the English is still awkward in many places, a few of which were called out by the referee, and I think the paper could be made more readable with further editing.

The more substantial concern of the referee relates to the use of the denser fluid model in place of more complicated rheology, and how the tuning of this model relates to convergence studies of the numerical methods. Personally I think that the results presented are sufficiently novel and promising to be worth publishing, but that the paper would indeed be stronger if some of these issues were clarified. The referee suggests that the model should first be tested on a simpler test case rather than Lituya Bay. A paper along those lines would also be valuable, but I realize that a major aspect of the present paper is to develop a better model of the Lituya Bay topography and to explore this particular event. Adding an additional simpler test case to this paper may not be feasible, but I encourage you to consider these concerns and try to at least clarify the tests you have done with different grid resolutions and parameter choices, and better address the questions of convergence of the numerical method as distinct from the tuning of the rheology model, landslide mass, topography, etc.

The development of better pre-event topography appears to be a major contribution of this work, and sharing it properly so that it can be accessed and properly cited will potentially increase its impact substantially. In your Data Availability section you list a URL that appears to be broken. I suggest you follow the guidance at
https://www.natural-hazards-and-earth-system-sciences.net/about/data_policy.html
and submit this to a repository that issues permanent DOIs and then add a proper bibliography item and citation to the paper. Suitable repositories for this work include www.designsafe-ci.org or zenodo.org.

Publishing the computer code developed for doing the simulations in a similar manner would also be valuable. This potentially allows readers to better understand your numerical modeling and the tests that have been performed, since not every aspect can be fully documented in the paper, even if the reader cannot run your code with purchasing the commercial Flow-3D software. It is also a good practice for reproducibility and may be beneficial to your own work in the long run if you need to reproduce or build on this work.

Editors comments on nhess-2019-285-manuscript-version5.pdf

Thank you for submitting the revised manuscript. Referee 1 was already satisfied with the previous version and Referee 2 continued to have a number of concerns, many of which you have addressed. However, there are still some problems that I see. Since Referee 2 has requested to be relieved from duty on this paper, I am listing them here and hope that you will be able to quickly resolve them and resubmit.

Thank you also for responding to my previous request to make the new bathymetry data and the settings for the computational code available in Zenodo.

(a) Ad 10. The referee noted that you use "center of gravity" in places where you might have meant "center of mass". I see that this has been changed in at least one place (p. 11, line 24), but there are still several places where "center of gravity" appears, e.g. p. 9 line 11, p. 11, line 27 and the captions of Figures 4 and 6. Please check that you have made the appropriate set of changes.

(b) Ad 11. The referee asked how you define "flow velocity" and you responded that it is the total vector with x-y-z components. Some places, such as p. 10 line 32, and in caption of Figure 10, you talk about the "flow velocity magnitude" (presumably the 2-norm of the vector, which could be clarified). However, in other places you still talk about the "flow velocity" as a scalar, e.g. p. 11, line 22: "Maximum velocity varies between 92-114 m/s..". Also many places on pages 13-14 and elsewhere. Here you also presumably mean "maximum velocity magnitude". Moreover, I agree with the referee that simply calling this "flow speed" or "flow current speed" is simpler than "velocity magnitude", and is standard terminology for the magnitude of the velocity vector.

(c) Ad 12. The referee asked about your statement that attenuation is responsible for both the decrease in magnitude and propagation speed of the wave. I am also confused by this section on page 15, lines 8-16, and by your response. You seem to be possibly mixing up the wave propagation speed (which is roughly sqrt(g*h) in the shallow water equations, for example), with the fluid speed (magnitude of (u,v,w)). The wave propagation speed depends primarily on the depth of the bay while the fluid speed can be greatly accelerated by water flowing down a slope and impacting the sea. The wave propagation speed should not attenuate as a wave propagates: even as the amplitude of the wave vanishes this sqrt(g*h) speed is still large in deep water. Please clarify this discussion. (And also I suggest using "speed" rather than "velocity" also for the wave propagation speed when you mean the scalar magnitude of the velocity.)

(d) Ad 3. The referee correctly notes that the English is awkward in many places, and while you have fixed this in a couple cases, I believe that it is still unacceptably poor in many other places. Once accepted, some copy editing of the paper will be done by the journal, and minor grammatical problems can be fixed then, but there are several places where it is very difficult to read currently and in some cases the intended meaning is not clear. I think it is essential that these be clarified before the paper is accepted rather than relying on the copy editing process. I realize English is not the authors' native language, but among the 5 authors there must be enough fluency to correct many of the worst offenses and at least make sure that the meaning is clear, and I urge all authors to go through the paper carefully with an eye to the language and meaning.

I have not attempted to flag every awkward sentence, but here are some examples (both major and very minor) that I came across in looking at the above issues. I think some work on the language is required on these and also elsewhere in the paper:

p. 2, line 25: "With these studies a significant effort could be achieved in understanding process behavior and hazard potential of landslide-induced tsunamis."
perhaps:
"With these studies significant understanding was achieved of the process and hazard potential of landslide-induced tsunamis."

p. 2, line 27: "addressing to the following research questions:"
Leave out "to"

p. 6, line 4: "according Fritz ..."
should be "according to Fritz..." and the same mistake appears elsewhere.

p. 9, line 20: "Since, for this case, the lack of direct observed data and since a proper set up and validation of the rockslide model, with accurate rheological parameters, is not possible with the adopted software Flow 3D, ..."
perhaps:
"Since in this case there is a lack of directly observed data, and since a proper set up and validation of the rockslide model, with accurate rheological parameters, is not possible with the software Flow 3D adopted for this study, ..."

p. 9, line 24: "The used porosity is based on..."
perhaps:
"The porosity parameter used is based on ..."

p. 9, line 26: "...but gives an appropriated approximation..."
I think "appropriate" is meant.

p. 14, line 35: "an according water surface..."
I think you mean "a corresponding water surface..." ?

p. 16, line 26: "In order to verify improvements of the outputs accuracy for finer used resolutions, a conformation of difference reduction in flow characteristics values, between each refinement, is provided."
Do you mean "outputs' accuracy" (possessive)?
"for finer used resolutions" --> "for the finer resolutions used"
What do you mean by "a conformation of difference reduction..."?

p. 16, line 39: "...determining the ordered discretization error can be challenging."
perhaps:
"... determining the order of accuracy can be challenging."

p. 16, line 39: "...since of the natural of the domain, a convergence test would not give much more information ..."
What is meant by "natural of the domain"?

p. 17, line 5: "Moreover, since there are no specific guidelines, the use of parameters to verify spatial convergence is of difficult choice."
It's not clear what you mean by "guidelines"? Do you mean the Flow 3D authors provide no guidelines, or where exactly would these come from? There are generally accepted approaches for doing a convergence study in general. Also the English is very awkward in the latter part of the sentence.
Perhaps:
"... the choice of parameters to verify spatial convergence is difficult."