Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis
Abstract The Aso-4 explosive eruption on Kyushu, Japan, 89,500 years ago was one of the biggest eruptions in the last one hundred millennia, with a magnitude of approximately M8. Modern society requires the likelihood of natural events with potentially disastrous consequences to be evaluated, even i...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2023-07-01
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| Series: | Journal of Applied Volcanology |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s13617-023-00131-8 |
| _version_ | 1827875618386083840 |
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| author | Willy Aspinall R. Stephen J. Sparks Brittain E. Hill Antonio Costa Charles Connor Hirohito Inakura Toshiaki Hasenaka Masaya Miyoshi Koji Kiyosugi Tomohiro Tsuji Masashi Ushioda |
| author_facet | Willy Aspinall R. Stephen J. Sparks Brittain E. Hill Antonio Costa Charles Connor Hirohito Inakura Toshiaki Hasenaka Masaya Miyoshi Koji Kiyosugi Tomohiro Tsuji Masashi Ushioda |
| author_sort | Willy Aspinall |
| collection | DOAJ |
| description | Abstract The Aso-4 explosive eruption on Kyushu, Japan, 89,500 years ago was one of the biggest eruptions in the last one hundred millennia, with a magnitude of approximately M8. Modern society requires the likelihood of natural events with potentially disastrous consequences to be evaluated, even if probabilities of occurrence are diminishingly small. For some situations, it is not satisfactory to assert an event scenario probability is “negligible” or can be “ignored”. Judicial hearings or litigation may require risk levels to be quantified, in which case, statements of scientific confidence could be decisive. Internationally, e.g., for nuclear site safety evaluations, event likelihoods on order of 10–7/year are often considered for quantitative assessment. At such hazard levels, this might include evaluating the proposition that a particular volcano can deliver a future super-eruption, a supposition that could be attached to Aso volcano. But, simplistically taking the average recurrence interval between past caldera-forming eruptions at a given volcano is an unreliable guide to the likelihood of a future repeat: each past event represented a unique set of tectonic and magmatic conditions within a continually evolving volcanic system. Such processes are not temporally stationary nor statistically uniform. To evaluate the probability of a new M8 event at Aso, within the next 100 years, we performed a comprehensive stochastic probability uncertainty analysis using a model implemented with advanced computational Bayes Net (BN) software. Our eruption process model is informed by multiple strands of evidence from volcanology, petrology, geochemistry and geophysics, together with estimates of epistemic (knowledge) uncertainty, adduced from reviews of published data, modelling and from expert judgement elicitation. Several lines of evidence characterise the likely structure, magmatic composition and eruptive state of the present-day Aso volcano, which has had numerous smaller eruptions since Aso-4. To calculate the probability of another M8 eruption of Aso, we implemented probabilistic ‘Importance Sampling’ in our model. With this approach, we find the chance of an Aso-4 scale eruption (characterised by mean volume 500 km3 DRE and approximate 90% credible interval [210 ‥ 1200] km3 DRE) is less than 1–in–1 billion in the next 100 years (i.e., < 10–9 probability). Based on current volcanological understanding and evidence, we believe this probability estimate is robust to within an order of magnitude. |
| first_indexed | 2024-03-12T17:10:33Z |
| format | Article |
| id | doaj.art-b2ca8e65faa14adeaaf20c7de8d26999 |
| institution | Directory Open Access Journal |
| issn | 2191-5040 |
| language | English |
| last_indexed | 2024-03-12T17:10:33Z |
| publishDate | 2023-07-01 |
| publisher | BMC |
| record_format | Article |
| series | Journal of Applied Volcanology |
| spelling | doaj.art-b2ca8e65faa14adeaaf20c7de8d269992023-08-06T11:05:16ZengBMCJournal of Applied Volcanology2191-50402023-07-0112112410.1186/s13617-023-00131-8Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysisWilly Aspinall0R. Stephen J. Sparks1Brittain E. Hill2Antonio Costa3Charles Connor4Hirohito Inakura5Toshiaki Hasenaka6Masaya Miyoshi7Koji Kiyosugi8Tomohiro Tsuji9Masashi Ushioda10University of BristolUniversity of BristolUniversity of South FloridaIstituto Nazionale Di Geofisica E VulcanologiaUniversity of South FloridaWest Japan Engineering Consultants, IncKumamoto UniversityFukuoka UniversityKobe UniversityThe Graduate School of Yamaguchi UniversityShikoku Research InstituteAbstract The Aso-4 explosive eruption on Kyushu, Japan, 89,500 years ago was one of the biggest eruptions in the last one hundred millennia, with a magnitude of approximately M8. Modern society requires the likelihood of natural events with potentially disastrous consequences to be evaluated, even if probabilities of occurrence are diminishingly small. For some situations, it is not satisfactory to assert an event scenario probability is “negligible” or can be “ignored”. Judicial hearings or litigation may require risk levels to be quantified, in which case, statements of scientific confidence could be decisive. Internationally, e.g., for nuclear site safety evaluations, event likelihoods on order of 10–7/year are often considered for quantitative assessment. At such hazard levels, this might include evaluating the proposition that a particular volcano can deliver a future super-eruption, a supposition that could be attached to Aso volcano. But, simplistically taking the average recurrence interval between past caldera-forming eruptions at a given volcano is an unreliable guide to the likelihood of a future repeat: each past event represented a unique set of tectonic and magmatic conditions within a continually evolving volcanic system. Such processes are not temporally stationary nor statistically uniform. To evaluate the probability of a new M8 event at Aso, within the next 100 years, we performed a comprehensive stochastic probability uncertainty analysis using a model implemented with advanced computational Bayes Net (BN) software. Our eruption process model is informed by multiple strands of evidence from volcanology, petrology, geochemistry and geophysics, together with estimates of epistemic (knowledge) uncertainty, adduced from reviews of published data, modelling and from expert judgement elicitation. Several lines of evidence characterise the likely structure, magmatic composition and eruptive state of the present-day Aso volcano, which has had numerous smaller eruptions since Aso-4. To calculate the probability of another M8 eruption of Aso, we implemented probabilistic ‘Importance Sampling’ in our model. With this approach, we find the chance of an Aso-4 scale eruption (characterised by mean volume 500 km3 DRE and approximate 90% credible interval [210 ‥ 1200] km3 DRE) is less than 1–in–1 billion in the next 100 years (i.e., < 10–9 probability). Based on current volcanological understanding and evidence, we believe this probability estimate is robust to within an order of magnitude.https://doi.org/10.1186/s13617-023-00131-8Aso volcanoJapanProbabilistic volcanic hazard assessmentSuper-eruption probability100-year forecastExpert elicitation |
| spellingShingle | Willy Aspinall R. Stephen J. Sparks Brittain E. Hill Antonio Costa Charles Connor Hirohito Inakura Toshiaki Hasenaka Masaya Miyoshi Koji Kiyosugi Tomohiro Tsuji Masashi Ushioda Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis Journal of Applied Volcanology Aso volcano Japan Probabilistic volcanic hazard assessment Super-eruption probability 100-year forecast Expert elicitation |
| title | Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis |
| title_full | Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis |
| title_fullStr | Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis |
| title_full_unstemmed | Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis |
| title_short | Aso volcano, Japan: assessing the 100-year probability of a new caldera-forming eruption based on expert judgements with Bayes Net and Importance Sampling uncertainty analysis |
| title_sort | aso volcano japan assessing the 100 year probability of a new caldera forming eruption based on expert judgements with bayes net and importance sampling uncertainty analysis |
| topic | Aso volcano Japan Probabilistic volcanic hazard assessment Super-eruption probability 100-year forecast Expert elicitation |
| url | https://doi.org/10.1186/s13617-023-00131-8 |
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