Post-eruption imaging of the Hunga caldera in Tonga has revealed new insights into how the structure of the volcano collapsed during the massive 2022 eruption. This event, which generated one of the most powerful volcanic explosions in recent history, also triggered a devastating tsunami that affected the surrounding Pacific region. Understanding the details of such collapses is crucial for predicting and mitigating future volcanic hazards. Volcanoes located underwater, or under the sea, can behave differently from those on land, often producing unique hazards. When volcanic activity interacts with seawater, the effects can vary dramatically. In the deep ocean, high water pressure can suppress explosive eruptions, making them less destructive. However, as volcanic activity occurs closer to the surface, where water pressure is lower, the interaction with seawater and the high temperatures of magma can lead to violent explosions. These explosions can generate tsunamis, though the exact conditions that lead to such events are not yet fully understood by scientists. To better understand the risks associated with underwater volcanic eruptions, an international team of researchers focused on the 2022 Hunga eruption in Tonga. They examined the rapid collapse of the volcano’s caldera, which may have played a significant role in amplifying the tsunami. A caldera is a large, bowl-shaped depression that forms when the ground above a magma chamber collapses after the magma is drained away. This process can be extremely rapid and violent, especially during powerful eruptions. Using detailed imaging techniques, scientists compared the seafloor topography before and after the eruption. Their findings showed that a caldera approximately four kilometers wide collapsed by nearly a kilometer during the event. This dramatic collapse likely contributed to the immense energy released, which could have been a key factor in generating the powerful tsunami. The research provides important clues about how underwater volcanic eruptions can lead to large-scale geological changes and natural disasters, helping scientists improve risk assessments and disaster preparedness in vulnerable regions.