A landmass born, watched, and lost
In December 2014, a submarine volcano in the Tongan archipelago began a Surtseyan eruption, the explosive interaction of magma and shallow seawater. By January 2015, this activity had built a new island, a circular tuff cone with a diameter of about 2 kilometers and a height of 120 meters. This new land connected two older, small, uninhabited islands: Hunga Tonga and Hunga Ha'apai.
The event was a rare opportunity. It was the first island of its kind to be formed and observed in the modern satellite era. Scientists, including a team from NASA, began monitoring it immediately, using satellite imagery and surface surveys to track its evolution. Initially, they predicted the fragile tuff cone would erode and vanish within months. However, chemical reactions between the volcanic ash and the warm ocean water consolidated the material into a harder rock called palagonite, and the island persisted.
For seven years, researchers watched as the island resisted erosion and life began to arrive. The first colonizers were not plants, but microbes that metabolized sulfur and atmospheric gases, similar to organisms found at deep-sea vents. Eventually, grasses and shrubs began to grow, and birds like sooty terns started to nest. The island was a natural laboratory for studying both geological and biological processes on new land.
The 2022 cataclysm
After weeks of smaller eruptions that began in December 2021, the volcano produced a cataclysmic explosion on January 15, 2022. The blast was the largest atmospheric explosion recorded by modern instruments, with an energy equivalent estimated between 4 and 18 megatons of TNT. People heard the sound thousands of kilometers away in Alaska.
The eruption column was unprecedented, blasting a plume of ash, gas, and water vapor to a height of 58 kilometers (36 miles) into the mesosphere. It is the tallest volcanic plume ever recorded. The event generated the most intense lightning storm ever observed, with a peak rate of over 2,600 flashes per minute. Some of this lightning occurred at altitudes of 20 to 30 kilometers.
The explosion generated atmospheric shockwaves that propagated around the entire planet multiple times. It also triggered a complex tsunami. One set of waves was generated by the blast's pressure wave, and another by the displacement of water from the volcano's collapse. These waves caused destruction across Tonga, with run-up heights reaching 15 meters on populated islands and up to 45 meters on the uninhabited island of Tofua. The tsunami crossed the entire Pacific, causing deaths in Peru. When the ash settled, the new island formed in 2015 was gone, along with large portions of the original Hunga Tonga and Hunga Ha'apai islands. In its place was a submarine caldera 4 kilometers wide, with its floor now 850 meters below sea level.