Deposits’ Morphology of the 2018 Hokkaido Iburi-Tobu Earthquake Mass Movements from LiDAR & Aerial Photographs

Round 1

Reviewer 1 Report

Hello, I suggest you consider the research undertaken in Hong Kong on H/L because this became incorporated into government planning policy concerning the location of new developments and the security of existing facilities and structures.

There are some grammatical errors that need to be resolved, plus the standard of English could be improved. Please avoid using 'I' or 'we'

Some specific comments:

First paragraph (33-42). This does not read very well at all, it is irrelevant to the topic. Please get to the point.

Line 45: Mw?

Line 47: slop

Line 50: pls confirm this is density as number/km2 and not true density (km2/km2)

Line 121: What are the symbols in eq2

Line 128-146: A good place to review HKG practice

Fig. 2: Its not clear as to how L on the image relates to L on the XS

Line 191: why is volume expressed as D?

Line 226-228: This determination of original slide surface depth assumes planar failure, pls comment on this. Also how do these depths relate to the known depth of pyroclastics in the region, because the paper states that failures occur at the boundary between these deposits and the underlying 'in situ ground.

Line 230: Is the length of the deposit the same as the runout length. Pls be clear on this

Line 237: Statistically, what is an acceptable value of R2 to allow the relationship to be considered as significant. This is important, given some of the low R2 values.

Line 248: epicentre of the earthquake?

Figs 4 and 5: I can see to very distinct curves on these graphs, only the lower one has a best-fit line

Line 284: which 'author'?

Line 367-374: just one example of poor English - difficult to follow

Line 378-379: How realistic is this?

 

 

Author Response

Thank you, please find the point to point in the attachment.

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper provides some geometrical relationships among different parameters for mass movements induced by the 2018, Mw (?) 6.6, Hokkaido Iburi-Tobu earthquake, compiled from LiDAR data and aerial photographs. In my opinion, the work is not well justified nor conducted. From my point of view, it should be rejected and not considered to be published in the Remote Sensing journal. In the following, I will show my main concerns about this work/manuscript.

 

1) First at all, the manuscript need an English revision in depth. Several terms, sentences and even sections are very difficult to understand.

2) Although it is not the main question, references must be also checked. Authors must use the required format for the journal. By the way, some of them are not well written, being some of them also incomplete. Evans et al. (2007) is not included in the references section, and Kasai and Yamada (2019) is not quoted in the manuscript.

3) Several sections along the manuscript must be clearly improved, starting with the abstract, very hard to understand and where readers cannot see clearly the goals of the conducted work. From the beginning, authors use the term landslide when they should use the term mass movement. What means in this context ‘complex terrain’ or ‘hazard purposes’? Authors claim that they want to contribute to existing databases but they do not show any data in the manuscript. Authors also claim that one of their goals is to ‘generate predictors for hazard mapping’. What are where are them? Are they the rough, biased and unreliable (inaccurate) obtained relationships?

4) My main concern, but not the only one, is that authors pretend to obtain results ‘solely’ using remote sensing data, as they claim, without any field survey, i.e., without staining their shoes. This is surprising for a field geologist or any Earth sciences researcher. It is not possible to know, for instance, the type of soil involved, if the mass movement is or not co-seismic, or what was the triggering mechanism, among other factors, without field surveys. Assumptions (‘One can then logically suppose that the slope shear strength was weakened before the HIT earthquake occurred’) must be corroborated at field, not in front of a computer screen. How it is possible ‘understand the mechanism of triggering’, as authors declare, using only remote sensing data without a later field survey?

5) Used data are not known. A detailed database including geometrical and geological parameters is required (and must be showed) for this type of studies. Why to use in this study some data and not others is a mystery for the reviewer and the potential readers. The reliability of the data is also unknown. Merge all data in order to obtain the relationships is astonishing. In this type of studies, these relationships are dependent, at least, on the type of mass movement and the type of soil, and also on other variables, as the distance to the rupture.

6) What is the real and practical goal of these unreliable and inaccurate relationships? It is not addressed in the manuscript. When authors proclaim that ‘the present contribution is a remote sensing contribution and not a geotechnical analysis’, they clearly reveal the importance of this work, none … from a geological or geotechnical perspective.

Author Response

To the anonymous reviewer:

Thank you for taking the time to read the paper my colleague and I had written, even if we obviously don't have the same views on this work. If you have some time, I would like to invite you to read this article in Nature, and hopefully you will be able to reflect on the nature of what you wrote:

https://www.nature.com/articles/d41586-019-02492-w

Regards.

Reviewer 3 Report

Dear authors:

The current contribution looks quite interesting, and the authors use a large database. From this large database of landslides during HIT earthquakes in the present study are selected some clear examples. Based on these examples, the authors correlate the travel distance of mudflows with environmental conditions. As an overall comment is the authors use the angle and not the derivative. In my understanding, one or two degrees in the angle is better than a second decimal place. For all my other comments, please see the attached annotated version of your pdf. There you will find several missing references that improve your contribution.  

Comments for author File: Comments.pdf

Author Response

Thank you, please find the point to point in the attachment.

Author Response File: Author Response.pdf