Effect of structural setting of source volume on rock avalanche mobility and deposit morphology

Duan, Zhao; Wu, Yan-Bin; Zhang, Qing; Li, Zhen-Yan; Yuan, Lin; Wang, Kai; Liu, Yang

doi:https://doi.org/10.5194/se-13-1631-2022

Articles | Volume 13, issue 10

https://doi.org/10.5194/se-13-1631-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/se-13-1631-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 13, issue 10

Research article

|

27 Oct 2022

Research article |

| 27 Oct 2022

Effect of structural setting of source volume on rock avalanche mobility and deposit morphology

Zhao Duan, Yan-Bin Wu, Qing Zhang, Zhen-Yan Li, Lin Yuan, Kai Wang, and Yang Liu

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Final revised paper (published on 27 Oct 2022)
Preprint (discussion started on 05 May 2022)

Interactive discussion

Status: closed

CC1:
'Comment on egusphere-2022-268', Xiao Yu, 09 May 2022

This is an interesting study. Just as the initial rock mass structure controls the expansion and accumulation characteristics of the rock after collapse, considering the accumulation form of the large rock collapse is of great significance to the prevention and control of rock collapse disasters. It should be noted that the rock mass will be broken and disintegrated during the long-distance migration, which may be a long-term behavior after the landslide failure. It is worth exploring whether the large boulders are the products of the damaged source and whether the unbroken large boulders show the characteristics consistent with the manuscripts after a long enough propagation distance. Future research can consider the impact of rock mass fragmentation on the migration and accumulation of large blocks, and how the accumulation of large rocks may imply the dynamic characteristics of disasters.

Citation: https://doi.org/10.5194/egusphere-2022-268-CC1
- AC1: 'Reply on CC1', Yanbin Wu, 31 May 2022
  
  Dear Xiao Yu,
  Thank you very much for your helpful comments.
  Certainly, just as you said “the rock mass will be broken and disintegrated during the long-distance migration”. There are avalanche events with rock mass disintegrated by discontinuous sets. Such as the Jiweishan rock avalanche in Chongqing, China, and Frank Slide in southwest Alberta, Canada.
  The orientation of large boulders in accumulation area may differ from that one in source area because factors including terrain and mass materials can also influence the orientation of large boulders. However, our experiments showed a similar orientation of large blocks before releasing and after releasing. It is noted that the sliding mass exhibits well-preserved initial discontinuous structures in the EI Magnifica rock avalanche (Magnarini et al. 2021). This is similar with our study.
  Thank you very much, the studies on rock mass fragmentation have been conducted in-depth (Lin, et al. 2020 and 2021; Bowman and Take, 2015), which is meaningful. We will pay attention to how the accumulation of large rocks may imply the dynamic characteristics of disasters in further studies.
  References:
  Magnarini, G., Mitchell, T. M., Goren, L., Grindrod, P. M., and Browning, J.: Implications of longitudinal ridges for the mechanics of ice-free long runout landslides, Earth and Planetary Science Letters, 574, 117177, https://doi.org/10.1016/j.epsl.2021.117177, 2021.
  Lin, Q., Cheng, Q., Li, K., Xie, Y., and Wang, Y.: Contributions of Rock Mass Structure to the Emplacement of Fragmenting Rockfalls and Rockslides: Insights From Laboratory Experiments, Journal of Geophysical Research: Solid Earth, 125, e2019JB019296, https://doi.org/10.1029/2019JB019296, 2020.
  Lin, Q., Wang, Y., Xie, Y., Cheng, Q., and Deng, K.: Multiscale effects caused by the fracturing and fragmentation of rock blocks in rock mass movement: Implications for rock avalanche propagation, Nat. Hazards Earth Syst. Sci. Discuss., 2021, 1-25, 10.5194/nhess-2021-127, 2021.
  Bowman, E. T. and Take, W. A.: The runout of chalk cliff collapses in England and France—case studies and physical model experiments, Landslides, 12, 225-239, 10.1007/s10346-014-0472-2, 2015.
  
  Citation: https://doi.org/10.5194/egusphere-2022-268-AC1
RC1:
'Comment on egusphere-2022-268', Anonymous Referee #1, 19 May 2022

The initial discontinuous sets play an important role for the happening of rock avalanches. The authors performed a series of mass flows with different initial configurations and with materials containing blocks and fine particles. This is an interesting experiment, in which the runout of these mass flows at different configurations showed both inhibiting and intensifying effects. However, there are still some points confused me, please clarify.

Figure 2, the caption is “experimental apparatus”, but what is mean the right part of the figures? Please clarify and provide more details.

L 110, how were the blocks produced? It should be specific and others can repeat the procedure.

In addition, I noticed that the sand the authors used to produce the blocks is with different colors. Does the attributes of the sand or sand blocks affect by the difference in colors? Besides that, is the particle size of the sand with different colors same?

What is the intention the different color blocks were used to simulate the large blocks in field? Is the intention to study the sequence of sliding mass during motion? Because I noted the blocks with different colors was placed in a same layer (Figure 6).

The results showed that the blocks contained relatively well the initial structures. Are avalanche events in field with a same phenomenon?

Citation: https://doi.org/10.5194/egusphere-2022-268-RC1
- AC1: 'Reply on CC1', Yanbin Wu, 31 May 2022
  
  Dear Xiao Yu,
  Thank you very much for your helpful comments.
  Certainly, just as you said “the rock mass will be broken and disintegrated during the long-distance migration”. There are avalanche events with rock mass disintegrated by discontinuous sets. Such as the Jiweishan rock avalanche in Chongqing, China, and Frank Slide in southwest Alberta, Canada.
  The orientation of large boulders in accumulation area may differ from that one in source area because factors including terrain and mass materials can also influence the orientation of large boulders. However, our experiments showed a similar orientation of large blocks before releasing and after releasing. It is noted that the sliding mass exhibits well-preserved initial discontinuous structures in the EI Magnifica rock avalanche (Magnarini et al. 2021). This is similar with our study.
  Thank you very much, the studies on rock mass fragmentation have been conducted in-depth (Lin, et al. 2020 and 2021; Bowman and Take, 2015), which is meaningful. We will pay attention to how the accumulation of large rocks may imply the dynamic characteristics of disasters in further studies.
  References:
  Magnarini, G., Mitchell, T. M., Goren, L., Grindrod, P. M., and Browning, J.: Implications of longitudinal ridges for the mechanics of ice-free long runout landslides, Earth and Planetary Science Letters, 574, 117177, https://doi.org/10.1016/j.epsl.2021.117177, 2021.
  Lin, Q., Cheng, Q., Li, K., Xie, Y., and Wang, Y.: Contributions of Rock Mass Structure to the Emplacement of Fragmenting Rockfalls and Rockslides: Insights From Laboratory Experiments, Journal of Geophysical Research: Solid Earth, 125, e2019JB019296, https://doi.org/10.1029/2019JB019296, 2020.
  Lin, Q., Wang, Y., Xie, Y., Cheng, Q., and Deng, K.: Multiscale effects caused by the fracturing and fragmentation of rock blocks in rock mass movement: Implications for rock avalanche propagation, Nat. Hazards Earth Syst. Sci. Discuss., 2021, 1-25, 10.5194/nhess-2021-127, 2021.
  Bowman, E. T. and Take, W. A.: The runout of chalk cliff collapses in England and France—case studies and physical model experiments, Landslides, 12, 225-239, 10.1007/s10346-014-0472-2, 2015.
  
  Citation: https://doi.org/10.5194/egusphere-2022-268-AC1
- AC2: 'Reply on RC1', Yanbin Wu, 24 Jul 2022
  
  Dear anonymous Referee:
  On behalf of my co-authors, we would like to express our sincere gratitude for your comments. We upload an attachment to answer your questions. Please check.
  
  Citation: https://doi.org/10.5194/egusphere-2022-268-AC2
RC2:
'Comment on egusphere-2022-268', Luigi Guerriero, 10 Jun 2022

Dear Editor, dear Authors:

This manuscript entitled “An experimental perspective on the effects of initial structures on rock avalanches’ propagation and sedimentary characteristics” presents results from a rock avalanche runout experiment, in terms of propagation characteristics and deposit morphology, to identify potential controlling action of geologic setting of the source volume (i.e. rock fragmentation due to discontinuities) and slope angle. The topic fits the scope of the journal and might be of interest for the scientific community, however, in my opinion, the manuscript, in its actual form, is not ready for publication in an international journal as Solid Earth. My major concern is related to the novelty that the paper brings to the scientific community, since the authors refers their interpretations to similar experiments already conducted. In addition, the significance of the experiment is limited by i) the lack of a specific geologic contextualization (i.e. it is not clear to me if the results of the experiment are of general interest or refer to a specific geologic predisposing condition), ii) an oversimplification of the analysis that use blocks of a single dimension and shape (i.e. in natural rock avalanches block shape and dimension can be extremely variable in relation to the local geologic setting and their interaction during motion is consistently related to their variable form and shape), iii) the lack of a robust interpretation of the results based on results from real rock avalanches field analyses (i.e. the authors substantially interpreted the results on the basis of the results of further experiments). Finally, the significance of the paper and the novelty bring to the knowledge of the topic do not emerge from the text. To facilitate the process of addressing the indicated limitations, I attached an annotated manuscript with specific comments.

Best regards,

Luigi Guerriero.

Citation: https://doi.org/10.5194/egusphere-2022-268-RC2
- AC3: 'Reply on RC2', Yanbin Wu, 24 Jul 2022
  
  Dear Luigi Guerriero:
  On behalf of my co-authors, we would like to express our sincere gratitude for your comments. We upload an attachment to answer your questions. Please check.
  
  Citation: https://doi.org/10.5194/egusphere-2022-268-AC3

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Yanbin Wu on behalf of the Authors (24 Jul 2022) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (25 Jul 2022) by Kei Ogata

RR by Luigi Guerriero (16 Aug 2022)

RR by Andrew Mitchell (21 Sep 2022)

ED: Publish subject to minor revisions (review by editor) (21 Sep 2022) by Kei Ogata

AR by Yanbin Wu on behalf of the Authors (27 Sep 2022) Author's response Author's tracked changes Manuscript

ED: Publish as is (01 Oct 2022) by Kei Ogata

ED: Publish as is (07 Oct 2022) by Arjen Stroeven (Executive editor)

AR by Yanbin Wu on behalf of the Authors (10 Oct 2022) Manuscript

Short summary

We studied the mobility and sedimentary characteristics of rock avalanches influenced by initial discontinuity sets with experimental methods. In the experiments, we set different initial configurations of blocks. The results revealed that the mobility and surface structures of the mass flows differed significantly. In the mass deposits, the block orientations were affected by their initial configurations and the motion processes of the mass flows.