the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Optimal probabilistic placement of facilities using a surrogate model for 3D tsunami simulations
Kenta Tozato
Shuji Moriguchi
Shinsuke Takase
Yu Otake
Michael R. Motley
Anawat Suppasri
Kenjiro Terada
Abstract. Tsunamis are associated with numerous uncertainties. Therefore, there has been an emphasis on setting the placement of infrastructure facilities based on probabilistic approaches. However, advanced numerical simulations have been often insufficiently utilized due to high computational costs. Therefore, in this study, we developed a framework that could efficiently utilize the information obtained from advanced numerical simulations for probabilistic assessment and investigation of the optimal placement of facilities based on calculated probability. Proper orthogonal decomposition (POD) techniques were employed for utilizing the data from the numerical simulations for probabilistic risk evaluation. We constructed a surrogate model in which POD was efficiently used to extract the spatial modes. The results of the numerical simulation were expressed as a linear combination of the modes, and the POD coefficients were expressed as a function of the uncertainty parameters to represent a result of an arbitrary scenario at a low computational cost. We conducted numerical simulations of the 2011 tsunami off the Pacific Coast caused by Tohoku Earthquake as an example of the method proposed in this study. The tsunami reached the target area, and the fault parameters of “slip” and “rake” were selected as the target uncertainties. We then created several scenarios in which these parameters were changed and conducted further numerical simulations using POD to construct a surrogate model. We selected the maximum inundation depth in the target area and the maximum impact force that acts on the buildings as the target risk indices, and we constructed a surrogate model of the spatial distributions of each indicator. Furthermore, we conducted Monte Carlo simulations using the constructed surrogate model and the information on fluctuations in uncertainties to calculate the spatial distribution of the failure criterion exceedance probabilities. We then used the Monte Carlo simulation results and a genetic algorithm to identify the optimal placement of facilities based on probability. We also discuss how the optimal placement changes according to differences in risk indices and the differences between parallel and series systems. The failure scenarios for each system are also discussed based on the failure probability. We show that the proposed method of efficiently utilizing advanced numerical simulation information was useful for conducting probabilistic hazard assessments and investigating the optimal placement of facilities based on probability theory.
Kenta Tozato et al.
Status: final response (author comments only)
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RC1: 'Comment on nhess-2022-208', Anonymous Referee #1, 11 Sep 2022
nhess-2022-208
Optimal probabilistic placement of facilities using a surrogate model for 3D tsunami simulations
Evaluation:
This is a good work and I think can be published. But the text is unclear in some places and misses important citations. It is important that authors clarify the items mentioned below, and add the suggested citations in order to make their work more international. My comments are given below. I look forward to reviewing the revised version. Best regards.
Comments:
Abstract:
Abstract is too long and is non-conclusive. Please try to add more quantitative results in your abstract. Also I suggest making your abstract shorter.
Figure is very similar to author team another article (https://doi.org/10.5194/nhess-22-1267-2022). Please try to make this figure different from your already-published article.
L26: what is meant by “…are not very compatible with probabilistic…?” please clarify.
L33/34: For PTHA, to give more diversity to your citations, please add the following two good articles: “Gopinathan et al. 2021” and “Heidarzadeh & Kijko 2011”.
Gopinathan, D., Hidarzadeh, M., Guillas, S. (2021). Probabilistic Quantification of tsunami current hazard using statistical emulation. Philosophical Transactions of the Royal Society A, 477, 20210180. https://doi.org/10.1098/rspa.2021.0180.
Hidarzadeh, M., Kijko, A. (2011). A probabilistic tsunami hazard assessment for the Makran subduction zone at the northwestern Indian Ocean. Natural Hazards, 56 (3), 577-593. https://doi.org/10.1007/s11069-010-9574-x.
L68: For the 2011 event please add a reference for clarity. I recommend the article by Prof Tsuji (Tsuji et al., 2011), as below:
Tsuji Y, Satake K, Ishibe T, Kusumoto S, Harada T, Nishiyama A, Kim HY, Ueno T, Murotani S, Oki S, Sugimoto M, Tomari J, Heidarzadeh M, Watada S, Imai K, Choi BH, Yoon SB, Bae JS, Kim KO, Kim HW (2011) Field surveys of tsunami heights from the 2011 Off the Pacific Coast of Tohoku, Japan, earthquake. Bulletin of the Earthquake Research Institute University of Tokyo 86:29–279 (in Japanese with English abstract)
L72: I think it is useful to add a line regarding the importance of this study. I recommend something like this: “The recent 2022 Tonga tsunami, which made global impacts (Heidarzadeh et al. 2022), showed that tsunami is an important costal disaster and studies like this work are needed”.
The reference is:
Heidarzadeh, M., Gusman, A., Ishibe, T., Sabeti, R., ŠepiÄ, J. (2022). Estimating the eruption-induced water displacement source of the 15 January 2022 Tonga volcanic tsunami from tsunami spectra and numerical modelling. Ocean Engineering, 261, 112165. https://doi.org/10.1016/j.oceaneng.2022.112165.
Figure 1: the colour bar cannot be read. Please ensure they can be read easily and add a legend for them. Are they “Wave amplitude (m)?”, add them.
L112: The 3D model is not clear? Please add a few references for that and explain more about it.
L113: What is this boundary condition? Explain more about it by adding the boundary equation and a few references.
L120: What are these data? Sea level? Velocity? Force?
L131: what is Lamda_k? what is d_j? every parameter needs to be defined as soon as they are used.
L139: again some parameters are not defined. Please ensure you define al parameters as soon as they are used throughout the text.
L200-204: it is not clear why authors considered only slip and rake for uncertainty? Please clarify this and try to convince the readers? Why not depth while depth is a very important factor regarding tsunami energy? Please clarify.
L203: regarding rake, you could refer to the following good articles that studied rake variations through teleseimic inversions (Gusman et al., 2014; Heidarzadeh et al., 2017):
Gusman, A. R., Murotani, S., Satake, K., Heidarzadeh, M., Gunawan, E., Watada, S., & Schurr, B. (2015). Fault slip distribution of the 2014 Iquique, Chile, earthquake estimated from ocean-wide tsunami waveforms and GPS data. Geophysical Research Letters, 42, 1053-1060. https://doi.org/10.1002/2014GL062604.
Heidarzadeh, M., Murotani, S., Satake, K., Takagawa, T., Saito, T. (2017). Fault size and depth extent of the Ecuador earthquake (Mw 7.8) of 16 April 2016 from teleseismic and tsunami data. Geophysical Research Letters, 44 (5), 2211–2219. https://doi.org/10.1002/2017GL072545.
Figure 5: I assume that the elevation is “Topography elevation (m)”. Please modify the legend.
L208: For the 2011 Tohoku data, add reference to Mori et al. (2011):
Mori, N., Takahashi, T., and The 2011 Tohoku Earthquake Tsunami Joint Survey Group, (2012), Nationwide post event survey and analysis of the 2011 Tohoku earthquake tsunami. Coastal Engineering Journal, 54 (1), 1-27. https://doi.org/10.1142/S0578563412500015.
Figure 8: what is the colour bar? Please write it in the figure next to the colour bar. This way the figure can be easier and readers can notice it instantly, instead of
reading your caption.
L254: It is not clear how the maximum impact force is calculated? Please write the equation tat you used to calculate the impact force here. Also please add a reference for that equation that you used for force calculations.
Figure 10: what is RBF? Mention the full name in the captions.
Figure 11: mention the legend of the colour bar in the Figure. Is that maximum impact force? Add it to the figure.
Figure 13: what is colour bar? Mention it in the figure.
End.
Citation: https://doi.org/10.5194/nhess-2022-208-RC1 - AC1: 'Reply on RC1', Kenta Tozato, 20 Sep 2022
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RC2: 'Comment on nhess-2022-208', Anonymous Referee #2, 29 Oct 2022
The comment was uploaded in the form of a supplement: https://nhess.copernicus.org/preprints/nhess-2022-208/nhess-2022-208-RC2-supplement.pdf
- AC2: 'Reply on RC2', Kenta Tozato, 07 Nov 2022
Kenta Tozato et al.
Data sets
K-Tozato/3D_tsunami_simulation: (Dataset_for_NHESS) Tozato, K. https://doi.org/10.5281/zenodo.6394294
Kenta Tozato et al.
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