A study of the 2022 Hunga volcano eruption in Tonga reveals that small underwater calderas can trigger outsized tsunamis, a risk that coastal businesses and insurers may have underestimated. The eruption produced a tsunami estimated at 40 meters high near the source, the largest ever recorded from an underwater volcanic event, despite Hunga's caldera being among the smallest in global databases.
The mechanism lies in rapid, piston-style caldera collapse. Comparing pre- and post-eruption seafloor maps, researchers found that the caldera sank by nearly one kilometer as the volcano erupted, displacing about 6.85 cubic kilometers of water in a short time. The collapse was enabled by a thin, broad magma reservoir roof that failed under a pressure drop of just 30 megapascals, roughly a quarter of the magma being drained.
For businesses, this suggests that current hazard models focused on larger volcanoes may miss threats from smaller, shallower systems. Coastal infrastructure, shipping lanes, and tourism-dependent economies near submarine volcanoes could face unanticipated tsunami risk. The authors caution that submarine caldera dynamics are still poorly understood, leaving significant uncertainty for disaster planning and insurance pricing.
While the study does not address business directly, its implications extend to risk assessment for coastal development and emergency preparedness. As the researchers note, the relative inaccessibility of submarine calderas means many hazardous volcanoes remain unmonitored, a gap that could translate into financial exposure for firms operating in vulnerable regions.