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Tsunami source inversion using time-derivative waveform of offshore pressure records to reduce the effects of non-tsunami components
https://nied-repo.bosai.go.jp/records/2933
https://nied-repo.bosai.go.jp/records/29338a320bda-a5f6-4c1e-b601-44f489ed7a61
| Item type | researchmap(1) | |||||||||||||||||||||||||||||||||
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| 公開日 | 2023-03-30 | |||||||||||||||||||||||||||||||||
| タイトル | ||||||||||||||||||||||||||||||||||
| 言語 | ja | |||||||||||||||||||||||||||||||||
| タイトル | Tsunami source inversion using time-derivative waveform of offshore pressure records to reduce the effects of non-tsunami components | |||||||||||||||||||||||||||||||||
| タイトル | ||||||||||||||||||||||||||||||||||
| 言語 | en | |||||||||||||||||||||||||||||||||
| タイトル | Tsunami source inversion using time-derivative waveform of offshore pressure records to reduce the effects of non-tsunami components | |||||||||||||||||||||||||||||||||
| 言語 | ||||||||||||||||||||||||||||||||||
| 言語 | eng | |||||||||||||||||||||||||||||||||
| 著者 |
Tatsuya Kubota
× Tatsuya Kubota
× Wataru Suzuki
× Takeshi Nakamura
× Naotaka Y. Chikasada
× Shin Aoi
× Narumi Takahashi
× Ryota Hino
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| 抄録 | ||||||||||||||||||||||||||||||||||
| 内容記述タイプ | Other | |||||||||||||||||||||||||||||||||
| 内容記述 | Offshore ocean bottom pressure gauges (OBPs) are often used to estimate the spatial distribution of the initial sea-surface height associated with offshore earthquakes (the tsunami source model). However, the sensors sometimes record pressure changes that are neither related to tsunamis nor seafloor coseismic displacements (the non-tsunami components) due to sensor rotation or tilt associated with ground shaking or due to long-term mechanical drift. These non-tsunami components can be a source of error when accurately estimating the tsunami source model and thus need to be removed to provide reliable coastal tsunami forecasts. This paper proposes a new method that uses time-derivative waveforms of the pressure time-series from OBP records to robustly estimate the tsunami source model, even when OBP data are perturbed by non-tsunami components. Using OBP data associated with the 2011 Off-Miyagi earthquake (Mw 7.2) and the 2016 Off-Mie earthquake (Mw 5.9), the performance of the method was evaluated when reducing artefacts due to non-tsunami components. The tsunami source model was found to be largely distorted when a conventional inversion method was used (because of the non-tsunami components). However, the artefact was dramatically reduced when using time-derivative waveforms, and the predicted coastal tsunami waveforms fitted reasonably with those of observations, thereby suggesting that the new method effectively suppresses artefacts caused by non-tsunami components. As the tsunami source models estimated from pressure and time-derivative waveforms should be similar when OBP data are not perturbed by non-tsunami components, we would be able to assess whether OBP data are perturbed by non-tsunami components by evaluating that the tsunami source models estimated from pressure waveforms and from time-derivative waveforms are similar to each other. | |||||||||||||||||||||||||||||||||
| 言語 | ja | |||||||||||||||||||||||||||||||||
| 抄録 | ||||||||||||||||||||||||||||||||||
| 内容記述タイプ | Other | |||||||||||||||||||||||||||||||||
| 内容記述 | Offshore ocean bottom pressure gauges (OBPs) are often used to estimate the spatial distribution of the initial sea-surface height associated with offshore earthquakes (the tsunami source model). However, the sensors sometimes record pressure changes that are neither related to tsunamis nor seafloor coseismic displacements (the non-tsunami components) due to sensor rotation or tilt associated with ground shaking or due to long-term mechanical drift. These non-tsunami components can be a source of error when accurately estimating the tsunami source model and thus need to be removed to provide reliable coastal tsunami forecasts. This paper proposes a new method that uses time-derivative waveforms of the pressure time-series from OBP records to robustly estimate the tsunami source model, even when OBP data are perturbed by non-tsunami components. Using OBP data associated with the 2011 Off-Miyagi earthquake (Mw 7.2) and the 2016 Off-Mie earthquake (Mw 5.9), the performance of the method was evaluated when reducing artefacts due to non-tsunami components. The tsunami source model was found to be largely distorted when a conventional inversion method was used (because of the non-tsunami components). However, the artefact was dramatically reduced when using time-derivative waveforms, and the predicted coastal tsunami waveforms fitted reasonably with those of observations, thereby suggesting that the new method effectively suppresses artefacts caused by non-tsunami components. As the tsunami source models estimated from pressure and time-derivative waveforms should be similar when OBP data are not perturbed by non-tsunami components, we would be able to assess whether OBP data are perturbed by non-tsunami components by evaluating that the tsunami source models estimated from pressure waveforms and from time-derivative waveforms are similar to each other. | |||||||||||||||||||||||||||||||||
| 言語 | en | |||||||||||||||||||||||||||||||||
| 書誌情報 |
ja : Geophysical Journal International en : Geophysical Journal International 巻 215, 号 2, p. 1200-1214, 発行日 2018-09 |
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| 出版者 | ||||||||||||||||||||||||||||||||||
| 言語 | en | |||||||||||||||||||||||||||||||||
| 出版者 | OXFORD UNIV PRESS | |||||||||||||||||||||||||||||||||
| ISSN | ||||||||||||||||||||||||||||||||||
| 収録物識別子タイプ | EISSN | |||||||||||||||||||||||||||||||||
| 収録物識別子 | 1365-246X | |||||||||||||||||||||||||||||||||
| DOI | ||||||||||||||||||||||||||||||||||
| 関連識別子 | 10.1093/gji/ggy345 | |||||||||||||||||||||||||||||||||
