The Role of Water and Weathering Processes in Landslides in Hungarian Loess Sediments
, Dóra Cseresznyés 3, Norbert Magyar 4, István Gábor Hatvani 2,5, Tamás Egedy 1,2,6, Zsuzsanna Szabó-Krausz 3, Beatrix Udvardi 7, Gergely Jakab 1,2,8, György Varga 1,2 and Zoltán Szalai 1,2,8_M._Sharp.png)
Round 1
Reviewer 1 Report
General: The paper does demonstrate that there is little correlation between precipitation patterns and mass movements in the study area. It is worthy of publication.
I will attach a pdf of my edited comments as in places the manuscript is awkwardly phrased.
I was also curious on the geochemical analyses. In my experience, there can be considerable lateral variation. I also enclose a photo of a loess bluff roadcut along the Missouri River in central Missouri, USA. There nearly vertical fractures in the loess along which there has been enhanced recharge and mineral dissolution, which is why these zones erode more easily. This has been attributed to dissolution of calcite cement in the loess. I suggest that the precipitated calcite the study observes is calcite that dissolved in the loess soils A-horizon, which was reprecipitated at greater depths.
I did not examine the statistical analyses in great detail. They seem adequate. I also have a number of questions and, especially in the introduction that should be addressed. These are given below:
Finally, I suggest the paper at end could be more specific about future studies that would clarify the causes of the movements in the study area,
Specific comments (numbers refer to line numbers):
1, Change title to “Role of water and weathering processes in mass movements in Hungarian loess sediments”
63-66, you need photos of the bluffs here.
90-93, show photos of the mass movements
92-93, are these 4 blocks the boxes on Figure 1d?
106-107, this is unclear – rain (presumably you mean runoff) cannot flow towards the Danube. Is a figure required?
115, a seawall along the Danube? Use a better term.
119, Fig 1, should the 4 actively moving blocks be shown on 1c? Also, this figure is so small that it is hard to read. Correct the legend in 1d.
Fig. 2, Certainly no obvious correlations are evident.
Table 2, with calcite 3 times as abundant as dolomite, it seems doubtful to me that this is the result of dolomite dissolution and reprecipitation as calcite. Calcite dissolution and o reprecipitation seems much more likely. See comment after line 283.
244-258, label the 4 significant change points clearly on the Figure 4. In the caption, differentiate between change points and change point horizons (gray shaded areas).
Fig.6, this figure is very hard to read.
290-303, good discussion!
332, “...ruin of loess.” This is unclear. Do you mean the mass movements?
366-369, delete.
Bluff is about 12 meters high. Note weathering along fractures attributed to dissolution of carbonate cement and calcite is much more soluble than dolomite.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
This manuscript tries to explain the effect of water and weathering process on the stability of loess-paleosol sequences based on a case study. The problem is important and worthy investigation. Some suggestions are attached below for improving the quality of this manuscript. Good luck.
1. The language should be improved. It’s too difficult to read for me. Maybe a professional language editing service is necessary.
2. The tittle should be revised, because the current one cannot convey the actual contribution of the manuscript.
3. The key words are too many.
4. Mass movement is a big word. Actually, debris flow, landslide, rock avalanche and etc. are all can be classified into the category of mass movement. So, it is not clear for the problem addressed in this manuscript. Maybe slope failure is appropriate.
5. The literature review must be improved. Stability of loess slopes has been widely investigated around the world. For example, many Chinese researches have published a lot of papers about the loess slopes within the loess plateau. It seems that the authors have ignored the contribution of these researches.
6. Soil erosion is also an important issue for the stability of loess slope especially when the slope contains paleosol.
7. The main problem of this manuscript lies in the application of the results. In other word, other researches would find it is difficult to follow, because the results are too specific and the general findings have not been disclosed. From this perspective, the conclusions must be re-written. In my opinion, the listed three points in the manuscript are too superficial, and they are just the summary of the observed phenomenon rather general laws.
Author Response
Answer to the Reviewer #2:
We are grateful to Reviewer 2. We accepted all of Your suggestions, which is summarized below:
This manuscript tries to explain the effect of water and weathering process on the stability of loess-paleosol sequences based on a case study. The problem is important and worthy investigation. Some suggestions are attached below for improving the quality of this manuscript. Good luck.
- The language should be improved. It’s too difficult to read for me. Maybe a professional language editing service is necessary.
Accepted. Improved the English in the text.
- The tittle should be revised, because the current one cannot convey the actual contribution of the manuscript.
Accepted, the title was modified to:
The role of water and weathering processes in the landslides in Hungarian loess sediments
- The key words are too many.
Accepted, we decreased the number of keywords.
- Mass movement is a big word. Actually, debris flow, landslide, rock avalanche and etc. are all can be classified into the category of mass movement. So, it is not clear for the problem addressed in this manuscript. Maybe slope failure is appropriate.
Accepted, we changed to landslide.
- The literature review must be improved. Stability of loess slopes has been widely investigated around the world. For example, many Chinese researches have published a lot of papers about the loess slopes within the loess plateau. It seems that the authors have ignored the contribution of these researches.
Accepted, literature from China was included (ref 8,9,11,16).
- Soil erosion is also an important issue for the stability of loess slope especially when the slope contains paleosol.
Thank you for your comment, our next study deal with the question of soil erosion. We completed the geological background of the area with some information from the sliding surface.
“The main sliding surface is the Tengelic Red Clay Formation which originated from aeolian material [23]. Earlier studies show that weathering processes affected to the red clay, for this reason clay minerals are the most important minerals [19], furthermore carbonate precipitation is observable in the top of the sliding surface [24].”
- The main problem of this manuscript lies in the application of the results. In other word, other researches would find it is difficult to follow, because the results are too specific and the general findings have not been disclosed. From this perspective, the conclusions must be re-written. In my opinion, the listed three points in the manuscript are too superficial, and they are just the summary of the observed phenomenon rather general laws.
Thank you for your comment. The conclusion was rewritten. The study aim was to show that not only 1-2 properties are responsible for the landslides in the paleosol-loess sequences. Furthermore, it is an important result that the statistical methods cannot show any connection between landslide and the water level, except two cases. We had not found similar results in the literature.
Round 2
Reviewer 2 Report
I am still not satisfied with the conclusion part of the resubmitted manuscript though it has been improved. It is suggested to summary the manuscript following a brief introdution to the background and research gap. In addition, an additional part is suggested to discuss the implications of the presented results to other future researches.
Author Response
Dear Reviewer 2,
Thank you for your work, We accepted your suggestion. The conclusion was extended to conclusion and outline, whchi you can read in the following:
The role of water and the stability of loess-paleosol bluffs is well established in the literature. According to the literature, landslides are connected to the water balance of loess-paleosol sequences, and the role of weathering is also an important factor. In this study, new methods were tested to understand the effect of the previous two properties, which were summarized as follows.
1) Even though the results of earlier studies show that rainfall amount and high water levels in the river are responsible for the landslides in the paleosol-loess sequences, the present study indicate that the effect of the amount of water in the landslides can only be conclusively demonstrated in two cases. In other cases, it may affect the other studied or unstudied properties.
2) One of the studied properties is the effect of the weathering. Geochemical modeling results show that weathering processes depend on the weather conditions (dry period, wet period, flood). Albite only weathers in wet periods, and kaolinite precipitation is faster during floods, while calcite is not precipitated during dry periods.
3) The other studied property is the effect of human activity. The result show, it is a complex factor that can facilitate landslide, due to the mass of houses, watering, and to the decreasing biodiversity. However, bluff stabilization, and building regulations can be one of the keys to decrease the anthropogenic effects.
Recent results indicate that the detected mass movements in the loess-paleosol bluff were connected to hydrological conditions, human activity and changes in the geochemical conditions of the loess.
As a methodological outlook, the study demonstrated that wavelet spectrum analysis and Bayesian changepoint analysis is capable of aiding the detection of environmental variables fundamentally responsible for the stability of loess-paleosol bluffs. A clear novelty of the research was the combined application of the aforementioned statistical tools and the assessment of changes in geochemical properties of loess in different weather conditions.
The proposed combined methodology can be applied in similar settings to account for the combined effect of environmental circumstances as the geochemical properties of the loess-paleosol buffs. The more areas are explored with this approach, the more we can understand the role of weathering in landslides with respect to their geochemical properties.
