The Hunga Tonga Tsunami Event of January 2022 and Its Global Reach
The January 2022 eruption of the submarine volcano Hunga Tonga Hunga Haʻapai near Tonga unleashed a tsunami whose first crest reached about 90 meters in height at Haʼapai. That peak was nine times higher than the waves that followed the catastrophic 2011 Japanese tsunami, a scale reported by a broad international study. The initial surge was extraordinarily large and then gradually diminished as it moved away from the source.
Researchers from multiple countries warn that this eruption should serve as a stark reminder to improve protections for communities at risk from volcanic tsunamis. They also highlight a gap in detection and monitoring systems, noting that volcanic tsunami sensors lag behind earthquake-based systems by roughly three decades.
Wave imagery and analysis show the event produced a distinctive footprint for researchers studying coastal hazards. The eruption occurred about 70 kilometers from Nukuʻalofa, the capital of Tonga, a distance that helped limit direct damage though the impact was still severe in nearby areas.
The team’s work involved analyzing ocean observation data that trace atmospheric pressure fluctuations and sea level oscillations, complemented by computer simulations validated with real-world observations. In the broader context of tsunamis linked to earthquakes, the largest waves prior to Tonga were generated by the 2011 Tōhoku event in Japan and the 1960 Chilean quake, both producing towering ocean surges but ultimately causing more landfall devastation due to their proximity and magnitude.
It could be a great tragedy
Lead researchers emphasize that the Tonga event should push authorities to better understand the triggers and signals of tsunamis born from volcanic activity. The eruption directly claimed five lives and caused widespread destruction, underscoring how proximity to volcanic centers or population hubs could dramatically amplify harm. The event’s location near a populated region demonstrated both the potential and the limits of current protective measures.
One senior scientist remarked that the event was enormous and unique on a global scale, highlighting the urgent need to invest in detection systems for volcanic tsunamis. The current gap means warning centers often remain unprepared for this class of hazard that behaves differently from earthquakes.
The research team reached its conclusions by examining long-term oceanographic records of atmospheric pressure changes, sea level shifts, and validating results with real-world data through simulations. This approach helped reveal how atmospheric dynamics can drive surface waves in addition to direct water displacement from eruptions.
Atmospheric Pressure Waves
Findings indicate the Tonga waves were not only the result of water being displaced by the eruption, but also a large-scale atmospheric pressure pulse that circled the planet multiple times. This dual mechanism produced a two-phase tsunami: an initial ocean wave sparked by atmospheric pressure fluctuations and, more than an hour later, a second wave driven by water displacement from the eruption itself.
Consequently, warning centers faced challenges because many early-warning systems focus on detecting water displacements rather than atmospheric pressure disturbances. This mismatch contributed to a delayed recognition of the very first wave in some regions.
Additionally, the January event was powerful enough to be detected across all major oceans and seas, appearing from the west coast of the United States to the North Pacific and even along Mediterranean coasts. The global reach underscored the far-reaching nature of volcanic tsunamis and their potential to affect distant shores far from the eruption site.
Experts note that volcanic island coastlines remain at risk, and the Tonga event reinforces the reality that coastal areas might face tsunamis even when they are not directly adjacent to a volcanic eruption. This conclusion comes from comparing the Tonga eruption with other events, reminding policymakers that living with volcanic hazards requires nuanced risk assessments rather than blanket policies about relocation or zoning alone.
Another co-author pointed to the value of effective warning systems and practical training for communities in danger. Real-time alerts, combined with clear guidance on what to do when a tsunami warning is issued, save lives. Strengthening monitoring of volcanic activity and ensuring research advances into high-quality, localized hazard assessments are essential steps toward reducing risk in volcanic regions.
A separate study released later from the University of Bath highlighted how the Tonga explosion generated atmospheric gravity waves that extended toward the edge of space, further illustrating the wide-scale atmospheric impact of such eruptions. These findings contribute to a growing understanding of the atmospheric and oceanic coupling that shapes volcanic tsunami behavior.
(Citations: ScienceDirect research on the Tonga eruption; ongoing analysis by international teams.)
In sum, the January 2022 Tonga eruption offers a sobering case study in the interconnectedness of ocean and atmosphere in volcanic tsunamis. It prompts a reevaluation of tsunami warning architecture and a renewed commitment to research that translates into faster, more reliable alerts for vulnerable coastal populations.
Notes from researchers indicate that the event serves as a catalyst for improving both real-time monitoring networks and the training of responders. The lessons extend beyond Tonga, informing global approaches to hazard preparedness in volcanic regions and highlighting the importance of integrating atmospheric signals into early-warning frameworks.