Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets
In this work we couple the Metropolis-Hastings algorithm with the volcanic ash transport model Tephra2, and present the coupled algorithm as a new method to estimate the Eruption Source Parameters of volcanic eruptions based on mass per unit area or thickness measurements of tephra fall deposits. Ou...
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Engineering::Environmental engineering Tephra2 Metropolis-Hasings Algorithm Yang, Qingyuan Pitman, E. Bruce Bursik, Marcus Jenkins, Susanna F. Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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In this work we couple the Metropolis-Hastings algorithm with the volcanic ash transport model Tephra2, and present the coupled algorithm as a new method to estimate the Eruption Source Parameters of volcanic eruptions based on mass per unit area or thickness measurements of tephra fall deposits. Outputs of the algorithm are presented as sample posterior distributions for variables of interest. Basic elements in the algorithm and how to implement it are introduced. Experiments are done with synthetic datasets. These experiments are designed to demonstrate that the algorithm works from different perspectives, and to show how inputs affect its performance. Advantages of the algorithm are that it has the ability to i) incorporate prior knowledge; ii) quantify the uncertainty; iii) capture correlations between variables of interest in the estimated Eruption Source Parameters; and iv) no simplification is assumed in sampling from the posterior probability distribution. A limitation is that some of the inputs need to be specified subjectively, which is designed intentionally such that the full capacity of the Bayes’ rule can be explored by users. How and why inputs of the algorithm affect its performance and how to specify them properly are explained and listed. Correlation between variables of interest in the posterior distributions exists in many of our experiments. They can be well-explained by the physics of tephra transport. We point out that in tephra deposit inversion, caution is needed in attempting to estimate Eruption Source Parameters and wind direction and speed at each elevation level, because this could be unnecessary or would increase the number of variables to be estimated, and these variables could be highly correlated. The algorithm is applied to a mass per unit area dataset of the tephra deposit from the 2011 Kirishima-Shinmoedake eruption. Simulation results from Tephra2 using posterior means from the algorithm are consistent with field observations, suggesting that this approach reliably reconstructs Eruption Source Parameters and wind conditions from deposits. |
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Asian School of the Environment |
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Asian School of the Environment Yang, Qingyuan Pitman, E. Bruce Bursik, Marcus Jenkins, Susanna F. |
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Yang, Qingyuan Pitman, E. Bruce Bursik, Marcus Jenkins, Susanna F. |
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Yang, Qingyuan |
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Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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tephra deposit inversion by coupling tephra2 with the metropolis-hastings algorithm : algorithm introduction and demonstration with synthetic datasets |
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2021 |
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sg-ntu-dr.10356-1466852023-02-28T16:41:53Z Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets Yang, Qingyuan Pitman, E. Bruce Bursik, Marcus Jenkins, Susanna F. Asian School of the Environment Earth Observatory of Singapore Engineering::Environmental engineering Tephra2 Metropolis-Hasings Algorithm In this work we couple the Metropolis-Hastings algorithm with the volcanic ash transport model Tephra2, and present the coupled algorithm as a new method to estimate the Eruption Source Parameters of volcanic eruptions based on mass per unit area or thickness measurements of tephra fall deposits. Outputs of the algorithm are presented as sample posterior distributions for variables of interest. Basic elements in the algorithm and how to implement it are introduced. Experiments are done with synthetic datasets. These experiments are designed to demonstrate that the algorithm works from different perspectives, and to show how inputs affect its performance. Advantages of the algorithm are that it has the ability to i) incorporate prior knowledge; ii) quantify the uncertainty; iii) capture correlations between variables of interest in the estimated Eruption Source Parameters; and iv) no simplification is assumed in sampling from the posterior probability distribution. A limitation is that some of the inputs need to be specified subjectively, which is designed intentionally such that the full capacity of the Bayes’ rule can be explored by users. How and why inputs of the algorithm affect its performance and how to specify them properly are explained and listed. Correlation between variables of interest in the posterior distributions exists in many of our experiments. They can be well-explained by the physics of tephra transport. We point out that in tephra deposit inversion, caution is needed in attempting to estimate Eruption Source Parameters and wind direction and speed at each elevation level, because this could be unnecessary or would increase the number of variables to be estimated, and these variables could be highly correlated. The algorithm is applied to a mass per unit area dataset of the tephra deposit from the 2011 Kirishima-Shinmoedake eruption. Simulation results from Tephra2 using posterior means from the algorithm are consistent with field observations, suggesting that this approach reliably reconstructs Eruption Source Parameters and wind conditions from deposits. Ministry of Education (MOE) National Research Foundation (NRF) Published version This work was partially supported by National Science Foundation Hazard SEES grant number 1521855 to G. Valentine, M. Bursik, E.B. Pitman, and A.K. Patra. This work comprises Earth Observatory of Singapore contribution no. 306. This research is partly supported by the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative (Project Name: Evaluating Unrest and Potential Hazards at Changbaishan Volcano, China; Project Number: NRF2018NRF-NSFC003ES-010) to S.F. Jenkins and Q. Yang. 2021-03-04T09:14:05Z 2021-03-04T09:14:05Z 2021 Journal Article Yang, Q., Pitman, E. B., Bursik, M., & Jenkins, S. F. (2021). Tephra deposit inversion by coupling Tephra2 with the Metropolis-Hastings algorithm : algorithm introduction and demonstration with synthetic datasets. Journal of Applied Volcanology, 10(1), 1-. doi:10.1186/s13617-020-00101-4 2191-5040 0000-0002-5631-889X https://hdl.handle.net/10356/146685 10.1186/s13617-020-00101-4 2-s2.0-85099805459 1 10 en NRF2018NRF NSFC003ES-010 Journal of Applied Volcanology © 2021 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. application/pdf |