Underwater Volcano Erupts Near Papua, Potentially Forming a New Island

An underwater volcano in the Bismarck Sea, just north of Papua New Guinea, could potentially give birth to a new island. Satellite imagery collected since early May shows the eruption is steadily moving towards the sea surface. The eruption was first detected following a series of earthquakes that shook the central Bismarck Sea floor. Since then, multiple satellites have monitored the volcanic activity from space, recording phenomena ranging from giant steam plumes and floating pumice rafts to a large thermal hotspot. For scientists, this phenomenon is both fascinating and challenging. The volcano is located in a region of the seafloor that remains poorly mapped, meaning much basic information about it is unknown. However, the stream of satellite data is helping researchers piece together a picture of the ongoing activity. Early signs of volcanic activity appeared on 8 May when seismometers recorded a series of undersea earthquakes. The United States’ National Aeronautics and Space Administration (NASA) later confirmed through satellite observations that an underwater volcanic eruption was indeed in progress. The discovery also highlights how little scientists understand about this seafloor region. To date, no detailed map exists that can pinpoint exactly which volcano is the source of the eruption. The area is filled with various geological structures such as faults, volcanic ridges, fissures, undersea cliffs, and active tectonic plate boundaries, making its geology extremely complex. Based on available evidence, the most likely source of the eruption is Titan Ridge, an area where two undersea tectonic plates meet. However, scientists still do not know which volcanic vent is active, how deep it was before the eruption began, or when the volcano last erupted. Over time, satellite images have shown the eruption getting closer to the sea surface. On 9 May, NASA’s Aqua and Terra satellites recorded a large white steam plume billowing from the ocean surface. Other satellites showed the steam column rising several kilometres into the atmosphere, while NASA’s PACE satellite detected a change in the colour of the seawater around the eruption site. Then, on 10 and 11 May, high-resolution images from the European Space Agency’s Sentinel-2 satellite and the NASA/USGS Landsat 9 satellite showed volcanic activity much closer to the water’s surface. Another important clue emerged on 12 May when the Suomi NPP satellite detected a thermal anomaly covering an area of about 7 square kilometres. Volcanologist Simon Carn from Michigan Technological University said the wide distribution of heat indicates that a large amount of high-temperature volcanic material is now very close to the sea surface. He also noted that the active eruptive vent is likely much shallower than previously estimated based on available seafloor maps. One of the most striking phenomena from this eruption is the formation of a large pumice raft drifting in the ocean. Pumice is a lightweight volcanic rock formed during eruptions that can float for long periods and even be carried hundreds of kilometres by ocean currents. Jim Garvin, chief scientist at the NASA Goddard Space Flight Center, said researchers are now waiting to see if the eruption will give birth to a new island. He noted that such a process is very rarely observed in its entirety using modern satellites. ‘We are now very excited to see if a new island will soon be born, something we very rarely get to observe directly via satellite while the process is underway,’ Garvin said. Even if new land successfully emerges above the sea surface, there is no guarantee the island will last long. The eruption could form a tuff cone, a structure created when magma comes into contact with seawater. However, the new land could also collapse or be quickly eroded. So far, the eruption is still classified as relatively weak. Carn explained that this is likely related to the volcano’s location along a volcanic ridge, where a transform fault meets a back-arc spreading centre. ‘Spreading zones are associated with less explosive activity, whereas the most explosive eruptions typically occur in subduction zones and involve large stratovolcanoes,’ Carn said. No one yet knows how long this volcanic activity will last. For comparison, an eruption on the same ridge in 1972 lasted only four days. Meanwhile, another eruption near the St. Andrew Strait, about 100 kilometres from the current site, lasted nearly four years after it began in 1957. If a new island truly emerges, scientists hope to study how plants, animals, and other life forms gradually begin to colonise the land. They will also observe how rain, erosion, and chemical weathering processes shape the evolution of the new island over time.