January 15 2022: the Hunga Tonga eruption and the global meteotsunami phenomenon
The underwater eruption of the Hunga Tonga Hunga Ha’apai volcano on January 15 2022 did more than break records. Its majestic blast sent a dramatic atmospheric and oceanic response around the world, linking a fierce tsunami in the Pacific with a surge of lightning in the eruptive gas column. The event also stirred a notable atmospheric disturbance that propagated around the globe, a meteotsunami that had not been seen in such strength for more than a century.
A collaboration among scientists from the Balearic Islands Oceanographic Center of the IEO CSIC, the University of the Balearic Islands, and IMEDEA documents this rare phenomenon. Published in Scientific Reports, their study examines the features of a global meteotsunami that reappeared in modern times after the Krakatoa eruption of 1883. Their work shows how the Tonga explosion triggered atmospheric and oceanic signals measurable by a vast network of sensors.
The eruption launched a rapid atmospheric disturbance that traveled the Earth at the speed of sound, looping around the planet up to three times in succession. This wave activity was detected by hundreds of barographs worldwide as energy spikes in the high frequency band ranging from two to 120 minutes. The simultaneous sea level measurements across the globe revealed significant oscillations in the tsunami frequency band at each step of the atmospheric wave, underscoring the global reach of the event. The combination of a sea level rise and circulating atmospheric energy marks this instance as a genuine global meteotsunami.
The most intense waves occurred off the Pacific coast, with sea levels sometimes surpassing one meter as the ocean responded to the sea wave formed at the volcano during the eruption. The Pacific Ocean showed clear signals of change in sea level caused by both the local tsunami and this wider meteotsunami. Yet the effects extended beyond the Pacific, with atmospheric and oceanic oscillations influencing distant shores and environments around the world.
Joan Villalonga, the leading author on the study, emphasizes that the Tonga event demonstrates two intertwined processes: a tsunami beginning at the eruption site and propagating toward the Pacific rim, and a meteotsunami created by the atmospheric wave that spread globally. The sheer scale and distribution of the signals highlight how atmospheric disturbances can drive oceanic responses far from their origin.
In the Pacific, the largest sea level perturbations were driven by the accompanying sea wave generated during the eruption, producing waves that in some locations exceeded a meter. The measured changes in sea level across the Pacific reflected the combined influence of the tsunami and the meteotsunami, revealing a complex interaction between local and global drivers of ocean motion. While meteotsunamis can be highly damaging, especially in constrained coastal basins, their energy is distributed differently than that of classical tsunamis, and their strength depends on atmospheric conditions and coastal geometry.
The meteotsunami did not remain a local curiosity. Although the amplitude and frequency of waves varied across regions, the atmospheric disturbance had global consequences, affecting coastal water levels and sea states far beyond the eruption site. This global imprint underscores the need to monitor atmospheric pressure changes and their interaction with coastal oceans to understand potential hazards and early warning systems.
Differences between a tsunami and a meteotsunami lie in their origins. A tsunami arises from local disturbances such as earthquakes or volcanic explosions, which create waves that can travel long distances at sea. A meteotsunami emerges when rapid atmospheric pressure changes push a wave into the sea, generating oscillations in sea level every few minutes to a few hours. While both events produce sea level oscillations with similar frequencies, the meteotsunami relies on atmospheric forcing rather than a seismic or volcanic sea source, and its energy can escalate in favorable harbor and bay resonances. Atmospheric events, while powerful, do not reach the same energy levels as earthquakes or volcanic blasts, but they can still produce significant coastal impacts when amplification mechanisms align. Resonance effects in ports and bays can magnify meteotsunami activity, and the potential size of a meteotsunami can be substantial in certain coastal settings, as observed near Ciutadella in Menorca when atmospheric forcing was strong and coastal geometry favorable.
For further context, the referenced work provides a detailed account of these dynamics and supports the view that global meteotsunami events are detectable through integrated observational networks. The findings are supported by data and analyses published in credible scientific outlets and summarized in ongoing discussions about atmospheric-ocean coupling and coastal hazard assessment.
References and further reading: a collaborative study by IEO CSIC Balearic Islands Oceanographic Center, the University of the Balearic Islands, and IMEDEA, as reported in Scientific Reports. The research highlights the value of sustained, global observation networks for understanding rapid atmospheric-ocean interactions and their implications for coastal communities. For additional information, see the published materials in credible scientific journals and the related discussions in the scientific community.
Note on sources: credible scientific publications provide the basis for these insights and are attributed to their respective institutions and journals as indicated in the cited works.