Oceanographers often point out that the surfaces of the Moon and Mars are mapped more precisely than much of the deep seafloor on Earth. That gap is especially clear in the Bismarck Sea, a deep basin north of Papua New Guinea. Its seafloor is geologically complex, with faults, volcanic structures, rifts, scarps, active subduction zones, and spreading zones lying at depths that are difficult to map in fine detail with sonar.

On May 8, 2026, satellites picked up signs of an unexpected underwater volcanic eruption in the Central Bismarck Sea. For volcanologists, the event highlighted a major problem: there were no detailed maps of the region, and the deep water setting of the eruption remains poorly understood.

The eruption is believed to be taking place along Titan Ridge, about 16 kilometers (10 miles) southeast of a submarine eruption recorded in 1972. Still, scientists do not yet agree on exactly which volcanic feature is active, how deep the vent was before the eruption, 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.