Ocean-wave phenomenon around Japan 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 around Japan, S-net and DONET, observed ocean waves caused by the Tonga eruption that started at approximately 13:00 JST (UTC + 0900) on January 15, 2022. We scrutinized the waveform records of the arriving ocean waves to evaluate their nature and found two significant disturbances between 20:00 and 21:00 and after 22:00. The first disturbance with a positive-polarity pulse dominated by long-period components (1000–3000 s) arrived at S-net and DONET stations between 20:00 and 21:00 from the southeast, corresponding to the direction of the short great circle between Tonga and Japan. This arrival was much earlier than expected for a direct tsunami from the volcano and can be explained by assuming that the waves propagated along the short great circle path 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 shorter period components (approximately 500 s). Most of the near-trench S-net stations recorded the 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 changes in both networks increased as the water depth decreases. This amplification behavior differed between the first and second disturbances, which is attributed to the differences in the natures of the arriving ocean and air waves. This study also found several arrivals of air-wave disturbances to be correlated with the ocean-wave phases, which implies that multiple disturbances of ocean-bottom pressures were generated by the interactions of several disturbances of air waves following the 2022 Tonga eruption with ocean waves. Graphical abstract

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).…”

Wave propagation of meteotsunamis and generation of free tsunamis in the sloping area of the Japan Trench for the 2022 Hunga–Tonga volcanic eruption

“…The S-net stations contain absolute pressure gauges (APGs). Analyses of these APG records have made it possible to detect meteotsunamis of atmospheric pressure origin (Kubota et al 2021) and volcanic eruption origin (Kubo et al 2022;Yamada et al 2022). Using the APG records observed in the 2022 Tonga event, we show the wavefields for the meteotsunami and the meteotsunami-induced free waves across the bathymetric slope areas from the trench to the nearshore in this study.…”

Efficacious hybrid and analytical and numerical methods; phase shift of the ultra-short pulses in optical fibers

“…1, 2, 3, 4, 5) of the real, imaginary, and absolute values that demonstrate solition and breather wave solution of Eqs. ( 7), ( 8), ( 9), (10), (15) to illustrate the perspective view of the solution, and the wave propagation pattern of the wave along x-axis. for the following values of the parameters a 0 = 1, λ = 3, µ = 2, r 1 = −1, a 0 = 2, λ = 5, µ = 6, r 1 = −3, s 1 = −1.…”

“…The use of the optical fiber is not limited to the transmission of the signals only, but also imaging and illumination but these usages are considered in the second priority [8].The optical fibers are usually wrapped in bundles for fetching the light into or images out of narrow spaces [9]. This technique has been used in many vital applications such as fiber lasers, fiber-scope, and fiber optic sensors [10].…”

“…The transmission of signals in optical fibers is based on a kernel with a translucent covering material with a lower refractive index [10]. A superconductor job of the optical fiber retains light in the center because the signals have a complete inner reflection [11].…”