日本地球惑星科学連合2023年大会

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セッション記号 H (地球人間圏科学) » H-DS 防災地球科学

[H-DS06] 津波とその予測

2023年5月22日(月) 15:30 〜 16:45 国際会議室 (IC) (幕張メッセ国際会議場)

コンビーナ:室谷 智子(国立科学博物館)、馬場 俊孝(徳島大学大学院産業理工学研究部)、座長:馬場 俊孝(徳島大学大学院産業理工学研究部)、Mohammad Heidarzadeh(University of Bath)

16:30 〜 16:45

[HDS06-05] Tsunami in the Japan Sea and Caribbean Sea Following the 2022 Tonga Volcanic Eruption

*何 東政1山田 真澄1森 信人1 (1.京都大学防災研究所)

キーワード:トンガ、津波、日本海、カリブ海

The volcanic eruption in Tonga in 2022 had a global impact on the atmosphere and ocean. The eruption generated an air pressure wave that induced a tsunami with a speed greater than 300 m/s, which was much faster than the average tsunami speed on the world ocean. The present study investigated the tsunami recorded on both the east and west coasts of the Pacific Ocean.
Eight hours after the eruption, the tsunami waves were recorded on the eastern Pacific coast. And about one hour later, the tide gauges in the Caribbean Sea also recorded the tsunami waves. The Caribbean Sea is located on the western Atlantic Ocean and is completely separated from the Pacific Ocean by Central America. The observation revealed that the air pressure wave had traveled across the land and induced the tsunami waves in the Caribbean Sea. To better understand the tsunami in the Caribbean Sea, we reconstructed the local air pressure wave and performed regional tsunami simulations. Our simulation reproduced the tsunami waves observed in the Caribbean Sea. The observed tsunami amplitudes on the western Caribbean Sea are about 2 cm, which are weaker than that generated on the eastern Caribbean Sea of about 5 cm.
We also performed a simulation on the west coast of the Pacific Ocean and the Japan Sea, which is separated from the Pacific Ocean by the Japanese archipelago. The results showed that the tsunami amplitudes were smaller on the north coast of the Japan Sea of 2–10 cm high, compared to that on the south coast of 2–5 cm.
In conclusion, the result shows that the air pressure wave generated by the volcanic eruption in Tonga can affect separated seas and oceans. In addition, our results demonstrate that the amplitude of the induced tsunami is stronger on the further side of the separated seas. The present study provides important insights into the impact of volcanic eruptions on tsunamis in separated water areas and highlights the importance of monitoring and preparing for such events in the future.