Oceanographers often point out that scientists have mapped the surfaces of the Moon and Mars in greater detail than much of Earth’s deep ocean. That contrast is especially striking in the Bismarck Sea north of Papua New Guinea, where the seafloor remains poorly understood despite its remarkable geological complexity. The region contains faults, volcanic structures, rifts, scarps, and active subduction and spreading zones, many located at depths that make detailed sonar mapping extremely difficult.
That lack of knowledge became especially apparent on May 8, 2026, when satellites detected signs of an unexpected submarine volcanic eruption in the Central Bismarck Sea. Researchers believe the activity is occurring along Titan Ridge, about 16 kilometers (10 miles) southeast of where another underwater eruption took place in 1972. Even so, scientists still cannot say with certainty which volcanic feature is erupting, how deep the active vent originally was, or when it last erupted.
“The good news is that there are huge opportunities to explore and learn using both government and commercial satellite platforms already in orbit,” said Jim Garvin, the chief scientist at NASA’s Goddard Space Flight Center.
Satellites Reveal the Eruption From Space
Seismometers first recorded a small swarm of earthquakes on May 8. Soon afterward, satellite observations confirmed that an underwater eruption was underway.
Beginning on May 9, NASA’s Aqua and Terra satellites captured images of white, steam rich volcanic plumes rising into the atmosphere. At the same time, the ocean color sensor aboard NASA’s PACE (Plankton, Aerosol, Cloud, Ocean Ecosystem) satellite detected large areas of discolored and disturbed water surrounding the eruption site.
Other satellites soon observed ash plumes reaching several kilometers into the sky. Higher resolution images collected by the European Space Agency’s Sentinel-2 satellite and NASA/USGS Landsat 9 on May 10 and 11 provided detailed views of activity near the ocean surface. A false color image (bands 7-6-5) highlighted the eruption’s infrared signature. Then, on May 12, the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument aboard Suomi NPP identified thermal anomalies covering about seven square kilometers.
“There must be a lot of hot material near the surface to generate so many thermal anomalies,” said Simon Carn, a volcanologist at Michigan Tech. “This suggests a fairly shallow eruption vent — much shallower than what’s implied by the existing bathymetry, which shows water depths of several hundred meters or more.”
Could a New Island Be Forming?
Satellite images also reveal intense activity at the ocean surface. Large plumes of discolored water, numerous steam and ash vents, and expansive pumice rafts (floating volcanic rocks) have all been observed. Medium and high resolution sensors operated by government agencies and commercial satellite companies have tracked these floating pumice fields as they stretch into long bands carried by surface currents.
“We’re now eagerly waiting to see if a new island is about to be born — something that we’ve only rarely been able to observe with satellites as it happens,” Garvin said.
If land does emerge above the water, scientists will closely monitor how it develops. The volcano could build a tuff cone with a long lived vent crater, or the new land could quickly collapse and erode away. There is also the possibility that the eruption could become significantly more explosive if seawater reaches the shallow magma chamber developing within the growing underwater volcano.
Why This Eruption May Stay Relatively Mild
So far, the eruption has been considerably less explosive than recent submarine eruptions such as Hunga Tonga-Hunga Ha’apai in 2022 and Fukutoku-Okanobain 2021.
Carn said a dramatic escalation appears unlikely because the eruption is associated with a volcanic ridge near the intersection of a transform fault and a back arc spreading center.
“Spreading centers are associated with less explosive activity, while the most explosive eruptions are usually along subduction zones and involve large stratovolcanoes.”
Scientists also do not know how long the eruption will continue. A nearby submarine eruption in 1972 lasted only four days, while another event roughly 100 kilometers away in the St. Andrew Strait continued for nearly four years after it began in 1957.
A Rare Opportunity to Study a New Island
Garvin and researchers from several institutions are continuing to monitor the eruption closely. He plans to use radar data from the NASA-ISRO NISAR satellite and the Canadian Space Agency’s RADARSAT Constellation Mission to map any new land that rises above the ocean and measure how its shape changes over time.
If the eruption creates a permanent island, Garvin believes it could become an exceptional natural laboratory. Researchers, whom he calls “island-nauts,” could study how the new land is colonized by plants and animals, how rainfall and chemical weathering reshape the landscape, and how erosion transforms the island over time, much as scientists did following the Hunga Tonga-Hunga Ha’apai eruption.
“This new eruption could present an even better opportunity for ‘island-naut’ exploration as we prepare to return to the Moon with women and men via Artemis IV,” he said.
