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Fig. 1 | Earth, Planets and Space

Fig. 1

From: Ocean-wave phenomenon around Japan due to the 2022 Tonga eruption observed by the wide and dense ocean-bottom pressure gauge networks

Fig. 1

a Map of the study area. Blue and cyan squares indicate S-net and DONET stations used in this study, respectively. Solid squares denote stations for which waveform records are shown in b. The orange arrow indicates a direction that is 140° clockwise from north, which roughly corresponds to the direction of the short great circle between Tonga and Japan. b Record section of ocean-bottom pressure from 20:00 JST (UTC + 0900) on January 15, 2022, to 03:00 JST on January 16, 2022. Blue and cyan lines denote waveform records of ocean-bottom pressure gauges at S-net and DONET stations, respectively. Significant phases (P1, P2, Q1, Q2, and Q3) are shaded in gray. Black bars indicate the theoretical arrival times of direct tsunamis. The origin time of the tsunami travel time was assumed at 13:00 (Gusman and Roger 2022). Green and pink bars indicate the theoretical travel times assuming propagation along the short great circle path from the Hunga Tonga‒Hunga Ha’apai volcano at velocities of 300 and 220 m/s, respectively. c Distribution of peak time of ocean-bottom pressure change between 20:00 and 01:00. d Distribution of peak amplitude of ocean-bottom pressure change at 20:00–21:30. e Same as c but at 22:00–01:00. f Distribution of the ratio of d the peak amplitude at 20:00–21:30 to e the peak amplitude at 22:00–01:00

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