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Abstract:
A major submarine volcanic eruption occurred on 15 January 2022 in the vicinity of the Tonga-Kermadec Islands in the Tropical Pacific Ocean. The eruption produced tsunami waves that were recorded throughout the World Ocean, including the Caribbean, Mediterranean and Black seas. The event attracted considerable scientific attention. Several thousand sea level and atmospheric pressure records have been examined, as well as numerous other geophysical data. A unique feature of the tsunami waves measured by coastal tide gauges and open-ocean bottom pressure recorders was the dual forcing mechanism that sent both oceanic waves –induced directly by the eruption and radiating outward from the source at the longwave speed of ~200 m/s – and atmospheric Lamb waves that circled the globe several times at the speed of sound of ~315 m/s. This dual source resulted in marked tsunami waves with heights of 2.0-2.5 m on the Pacific coasts of Chile, the US , New Zealand, Japan and the Aleutian Islands. The “atmospheric” waves arrived first, but the direct oceanic waves were much higher. In the Atlantic and Mediterranean, the waves were mostly of atmospheric origin (except on the coast of Argentina). Numerical models of the event show generally good agreement with observation. Global maps also reveal regional “hot spots”, where the tsunami heights were greatest. On the Atlantic Coast of the US, arrival of the Tonga tsunami coincided with hurricane generated waves to produce a hazardous double jeopeordy wave event.
