the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 16 Feb 2024
How water, temperature and seismicity control the preparation of massive rock slope failure (Hochvogel, DE/AT)
Abstract. The increasing hazard of major rock slope failures, exacerbated by climate change, underscores the importance of anticipating pre-failure process dynamics. While standard triggers are recognized for small rockfalls, few comprehensive driver quantifications exist for massive pre-failure rock slopes. Here we exploit >4 years multi-method high-resolution monitoring data from a well-prepared high-magnitude rock slope instability. To quantify and understand the effect of possible drivers – water from rain and snowmelt, internal rock fracturing and earthquakes – we correlate slope displacements with environmental data, local seismic recordings and earthquake catalogues. During the snowmelt phase, displacements are controlled by meltwater infiltration with high correlation and a time lag of 4–9 days. During the snow-free summer, rainfall drives the system with a time lag of 1–16 h for up to several days without a minimum activation rain sum threshold. Detected rock fracturing, linked to temperature and freeze-thaw cycles, is predominantly surface-near and unrelated to displacement rates. A classic Newmark analysis of recent and historic earthquakes indicates a low potential for immediate triggering of a major failure at the case site, unless it is already very close to failure. Seismic topographic amplification of the peak ground velocity at the summit ranges from a factor of 2–11 and is spatially heterogeneous, indicating a high criticality of the slope. The presented methodological approach enables a comprehensive rockfall driver evaluation and indicates where future climatic changes, e.g. in precipitation intensity and frequency, may alter the preparation of major rock slope failures.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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Supplement
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(5329 KB) - Metadata XML
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Supplement
(6766 KB) - BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
- RC1: 'Comment on egusphere-2024-231', Maximillian Van Wyk de Vries, 09 Mar 2024
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CC1: 'Comment on egusphere-2024-231', Giacomo Medici, 12 Mar 2024
General comments
Good and well presented research on rock failures with an angle on snowmelt. The manuscript needs some minor/moderate changes before publication. Please, refer to the specific comments to fix the issues.
Specific comments
Line 1. “Exacerbated by climate change”. Please, be more specific at least in the introduction. You need to explain that due to the changes of the climate the rainfall and snow falls distributions may vary over the hydrological years. If this point is valid also the frequency of the avalanches/landslides can change.
Lines 36-39. “Possible rockfall drivers and triggers... human or animal activity”. Please, add relevant literature below that shows how large volumes of water melts from snow in spring in mountainous areas. All areas characterized by rock slope failures.
- Lorenzi, V., Banzato, F., Barberio, M.D., Goeppert, N., Goldscheider, N., Gori, F., Lacchini, A., Manetta, M., Medici, G., Rusi, S. and Petitta, M., 2024. Tracking flowpaths in a complex karst system through tracer test and hydrogeochemical monitoring: Implications for groundwater protection (Gran Sasso, Italy). Heliyon, 10(2).
- Kawagoe, Saeki, So Kazama, and Priyantha Ranjan Sarukkalige. Assessment of snowmelt triggered landslide hazard and risk in Japan. Cold Regions Science and Technology. 58, no. 3 (2009): 120-129.
- Krøgli, I.K., Devoli, G., Colleuille, H., Boje, S., Sund, M. and Engen, I.K., 2018. The Norwegian forecasting and warning service for rainfall-and snowmelt-induced landslides. Natural hazards and earth system sciences. 18(5), pp.1427-1450.
Line 94. Please, disclose the 3 to 4 specific objectives of your research by using numbers (e.g., i, ii, and iii).
Lines 96-125. Add detail on the stratigraphy of the study sites. Age of the dolostones (maybe Triassic)? Geological formations or groups? This change represents detail on spatial heterogeneities that you discuss in your manuscript.
Lines 96-125. Provide detail on presence of faults that can represent the spatial heterogeneities of the rock that you mention in your manuscript.
Line 255. The majority of the snowmelt occurs in April in these regions. Thus, “the warm summer months” actually this time incorporates half part of the spring. Please, fix the statement.
Line 399. Please, provide more detail on the geological nature of the spatial heterogeneities.
Lines 443-620. Integrate the three references suggested above on large volumes of water melted from snow in areas affected by rock slope failures.
Figures and tables
Figure 2. I would insert the larger view on the left, and smaller one on the right.
Figures 3 and 4. There are words on the vertical axes which are un-readable.
Figures 5 to 9. The equation, “R2” and “p” in the third graphs are un-readable.
Citation: https://doi.org/10.5194/egusphere-2024-231-CC1 -
RC2: 'Comment on egusphere-2024-231', Anonymous Referee #2, 18 Mar 2024
This is a really interesting analysis of data from a highly-instrumented rock mass instability, and is undoubtedly an important contribution to understanding the proximal drivers of small-magnitude displacement events in large slope failures. Analyzing multiple drivers in time series with instrumentation on both displacements and cracking is state of the art and the analyses are done carefully using appropriate methods in my view. The conclusions that water supply rate and timing are the key driver of displacements is not exactly surprising but this is shown here in a compelling and quantitative way, in high time resolution. That the cracking detected was mostly near-surface means that its relevance to the displacement problem is limited, but still this is very useful in separating the effects of temperature and water on the overall system. Therefore, most of my comments are meant to clarify the manuscript, which in general is very clearly written and maintains a tight focus on the data and analysis.
Line 1. a sweeping motivational statement but too general I think, to say that climate change would in any given region always exacerbate instabilities or the hazards from them.Line 2-3. what are "driver quantifications"?
The first two sentences are written more densely with jargon and less clearly than the rest of the abstract. Like most abstracts, this one would be stronger if the first two sentences were simply deleted. Get straight to what you did and leave the motivating for the introduction.
Line 4: is there a less jargon-laden way to say "well-prepared high magnitude rock slope instability"? On first read this geomorphologist wondered what "prepared" meant in context; you're referring to natural preparation of the rock mass for failure, but at this point in the text it could mean well-prepared by people for monitoring or something else.
83-90 "Due to its magnitude, ... four relevant drivers remain..." This seems like it would fit better in the following section that describes the field site
86 Wind is a bit too easily dismissed here, given that it can apply stress to an entire mountainside at once, and that subcritical cracking occurs under very low stresses
126 US Geological Survey
216 Please define Newmark displacement in a sentence (or parenthetical) for those outside your immediate field
305 "matching the conclusions of Dietze et al" delete, this is a discussion point, not results, and is already discussed below in better context
421-422 Perhaps be more specific in this conclusion that it's the input rate and timing of water e.g. intensity/speed of snowmelt - the rate matters, not just whether and how much water is there
424 "In the light of ongoing climatic changes that lead to more frequent and intense heavy precipitation events and faster snowmelt," are these in evidence in your paper, again I think this is too generalized. In the region of Hochvogel, are there specific projections that indicate these changes?
Citation: https://doi.org/10.5194/egusphere-2024-231-RC2 - AC1: 'Comment on egusphere-2024-231', Johannes Leinauer, 25 Apr 2024
Interactive discussion
Status: closed
- RC1: 'Comment on egusphere-2024-231', Maximillian Van Wyk de Vries, 09 Mar 2024
-
CC1: 'Comment on egusphere-2024-231', Giacomo Medici, 12 Mar 2024
General comments
Good and well presented research on rock failures with an angle on snowmelt. The manuscript needs some minor/moderate changes before publication. Please, refer to the specific comments to fix the issues.
Specific comments
Line 1. “Exacerbated by climate change”. Please, be more specific at least in the introduction. You need to explain that due to the changes of the climate the rainfall and snow falls distributions may vary over the hydrological years. If this point is valid also the frequency of the avalanches/landslides can change.
Lines 36-39. “Possible rockfall drivers and triggers... human or animal activity”. Please, add relevant literature below that shows how large volumes of water melts from snow in spring in mountainous areas. All areas characterized by rock slope failures.
- Lorenzi, V., Banzato, F., Barberio, M.D., Goeppert, N., Goldscheider, N., Gori, F., Lacchini, A., Manetta, M., Medici, G., Rusi, S. and Petitta, M., 2024. Tracking flowpaths in a complex karst system through tracer test and hydrogeochemical monitoring: Implications for groundwater protection (Gran Sasso, Italy). Heliyon, 10(2).
- Kawagoe, Saeki, So Kazama, and Priyantha Ranjan Sarukkalige. Assessment of snowmelt triggered landslide hazard and risk in Japan. Cold Regions Science and Technology. 58, no. 3 (2009): 120-129.
- Krøgli, I.K., Devoli, G., Colleuille, H., Boje, S., Sund, M. and Engen, I.K., 2018. The Norwegian forecasting and warning service for rainfall-and snowmelt-induced landslides. Natural hazards and earth system sciences. 18(5), pp.1427-1450.
Line 94. Please, disclose the 3 to 4 specific objectives of your research by using numbers (e.g., i, ii, and iii).
Lines 96-125. Add detail on the stratigraphy of the study sites. Age of the dolostones (maybe Triassic)? Geological formations or groups? This change represents detail on spatial heterogeneities that you discuss in your manuscript.
Lines 96-125. Provide detail on presence of faults that can represent the spatial heterogeneities of the rock that you mention in your manuscript.
Line 255. The majority of the snowmelt occurs in April in these regions. Thus, “the warm summer months” actually this time incorporates half part of the spring. Please, fix the statement.
Line 399. Please, provide more detail on the geological nature of the spatial heterogeneities.
Lines 443-620. Integrate the three references suggested above on large volumes of water melted from snow in areas affected by rock slope failures.
Figures and tables
Figure 2. I would insert the larger view on the left, and smaller one on the right.
Figures 3 and 4. There are words on the vertical axes which are un-readable.
Figures 5 to 9. The equation, “R2” and “p” in the third graphs are un-readable.
Citation: https://doi.org/10.5194/egusphere-2024-231-CC1 -
RC2: 'Comment on egusphere-2024-231', Anonymous Referee #2, 18 Mar 2024
This is a really interesting analysis of data from a highly-instrumented rock mass instability, and is undoubtedly an important contribution to understanding the proximal drivers of small-magnitude displacement events in large slope failures. Analyzing multiple drivers in time series with instrumentation on both displacements and cracking is state of the art and the analyses are done carefully using appropriate methods in my view. The conclusions that water supply rate and timing are the key driver of displacements is not exactly surprising but this is shown here in a compelling and quantitative way, in high time resolution. That the cracking detected was mostly near-surface means that its relevance to the displacement problem is limited, but still this is very useful in separating the effects of temperature and water on the overall system. Therefore, most of my comments are meant to clarify the manuscript, which in general is very clearly written and maintains a tight focus on the data and analysis.
Line 1. a sweeping motivational statement but too general I think, to say that climate change would in any given region always exacerbate instabilities or the hazards from them.Line 2-3. what are "driver quantifications"?
The first two sentences are written more densely with jargon and less clearly than the rest of the abstract. Like most abstracts, this one would be stronger if the first two sentences were simply deleted. Get straight to what you did and leave the motivating for the introduction.
Line 4: is there a less jargon-laden way to say "well-prepared high magnitude rock slope instability"? On first read this geomorphologist wondered what "prepared" meant in context; you're referring to natural preparation of the rock mass for failure, but at this point in the text it could mean well-prepared by people for monitoring or something else.
83-90 "Due to its magnitude, ... four relevant drivers remain..." This seems like it would fit better in the following section that describes the field site
86 Wind is a bit too easily dismissed here, given that it can apply stress to an entire mountainside at once, and that subcritical cracking occurs under very low stresses
126 US Geological Survey
216 Please define Newmark displacement in a sentence (or parenthetical) for those outside your immediate field
305 "matching the conclusions of Dietze et al" delete, this is a discussion point, not results, and is already discussed below in better context
421-422 Perhaps be more specific in this conclusion that it's the input rate and timing of water e.g. intensity/speed of snowmelt - the rate matters, not just whether and how much water is there
424 "In the light of ongoing climatic changes that lead to more frequent and intense heavy precipitation events and faster snowmelt," are these in evidence in your paper, again I think this is too generalized. In the region of Hochvogel, are there specific projections that indicate these changes?
Citation: https://doi.org/10.5194/egusphere-2024-231-RC2 - AC1: 'Comment on egusphere-2024-231', Johannes Leinauer, 25 Apr 2024
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Johannes Leinauer
Michael Dietze
Sibylle Knapp
Riccardo Scandroglio
Maximilian Jokel
Michael Krautblatter
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(5329 KB) - Metadata XML
-
Supplement
(6766 KB) - BibTeX
- EndNote
- Final revised paper