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

Abstract

Ocean-bottom pressure gauges of wide and dense ocean-bottom observation networks in Japan, S-net and DONET, observed ocean waves due to the Tonga eruption that occurred at approximately 13:00 JST (UTC + 9) on January 15, 2022. We scrutinized their waveform records to clarify the nature of the arriving ocean waves, and found two significant disturbances between 20:00–21:00 and after 22:00. The first disturbance with a positive-polarity pulse and significant long-period components (1000–3000 s) arrived at S-net and DONET stations between 20:00–21:00 from the southeast, corresponding to the direction of the great circle of Tonga as seen from Japan. This arrival was much earlier than expected for a direct tsunami from the volcano and can be explained by assuming the propagation along the great circle path between Japan and Tonga at a velocity of approximately 300 m/s. After 22:00, significant phases dominated by relatively shorter period components (< 1000 s) arrived from the southeast direction in both observation networks. In DONET, another phase arrived from the south-southeast direction at approximately 23:30 with significant shorter period components (approximately 500 s). Most of the near-trench S-net stations recorded a peak amplitude during the first disturbance, whereas the near-coast S-net stations and DONET stations observed their peak after 22:00. The amplitudes of ocean-bottom pressure change were amplified as the water depth decreases. This amplification behavior differed between the first and second disturbances, and it may have been caused by differences in the dominant period of the arriving ocean waves, as well as differences in their generation mechanisms. This study also found several arrivals of air-wave disturbances that were correlated with the ocean-wave phases, which implies that the multiple disturbances of ocean-bottom pressure were generated by the interactions of several atmospheric pressure waves following the 2022 Tonga eruption with ocean waves.

Tsunami Triggered by the Lamb Wave From the 2022 Tonga Volcanic Eruption and Transition in the Offshore Japan Region

“…The observations in Japan are more complicated because of the varying water depths. DONET stations observed larger amplitudes than S‐net stations at times corresponding to a velocity of 0.2 km/s (Kubo et al., 2022) since the water depth in the south‐east of DONET is about 4,000 m (see Figure 4b).…”

“…Two major atmospheric waves are involved; the atmospheric Lamb wave, a non‐dispersive atmospheric wave traveling along the earth's surface horizontally at the speed of 0.31 km/s (Lamb, 1881; Nishida et al., 2014; Press & Harkrider, 1962), and some modes of the acoustic gravity waves traveling at the speed 0.2–0.22 km/s (Harkrider & Press, 1967; Kubota et al., 2022; Press & Harkrider, 1966). Since the average tsunami speed in the Pacific Ocean is close to these waves (about 0.2 km/s), the mechanism of air‐sea coupling becomes complex (Kubo et al., 2022; Kubota et al., 2022).…”

Global fast-traveling tsunamis driven by atmospheric Lamb waves on the 2022 Tonga eruption

“…Global ocean bottom pressure gauge data from the Deep-ocean Assessment and Reporting of Tsunamis (DART) system of the National Oceanic and Atmospheric Administration (NOAA) are available from https://www.ndbc.noaa.gov/. Ocean bottom pressure gauge data around Japan from the Seafloor observation network for earthquakes and tsunamis along the Japan Trench (S-net) ( 34 ) and Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET) ( 35 ) of National Research Institute of Earth Science and Disaster Resilience (NIED) ( 36 ) are available from https://doi.org/10.17598/nied.0007-2022-001 and https://doi.org/10.17598/nied.0008-2022-001, respectively. Global coastal tide gauge data were downloaded from the website of the Intergovernmental Oceanographic Commission (IOC) (https://www.ioc-sealevelmonitoring.org).…”

Quantifying magma overpressure beneath a submarine caldera: A mechanical modeling approach to tsunamigenic trapdoor faulting near Kita-Ioto Island, Japan

“…Submarine volcanoes have the potential to bring severe damage to local and even global societies with volcanic tsunamis, as highlighted by recent tsunami events related to the 15 January 2022 eruption of Hunga Tonga-Hunga Ha'apai, Tonga (e.g., Kubota et al, 2022;Lynett et al, 2022;Purkis et al, 2023;Borrero et al, 2023;Kubo et al, 2022), or the 22 December 2018 eruption of Anak Krakatau, Indonesia (e.g., Grilli et al, 2019;Muhari et al, 2019;Heidarzadeh, Ishibe, et al, 2020;Heidarzadeh, Putra et al, 2020;Mulia et al, 2020;Ye et al, 2020), and by historical events listed in Day (2015) and Paris et al (2014), some of which caused over manuscript submitted to Journal of Geophysical Research: Solid Earth hundreds to thousands of fatalities. Yet, it is often challenging to investigate submarine volcanoes due to the lack of on-site monitoring systems.…”