A new source of danger for humanity has been discovered on the ocean floor

An international team of volcanologists used an artificial intelligence algorithm to identify 73 previously unknown volcanic calderas on the floor of the World Ocean — giant crater-like depressions that form after the Earth's crust collapses above an emptied magma chamber. The discovery more than triples the number of documented underwater calderas. The study was published in the journal Communications Earth & Environment (CEE).

A caldera is not a volcanic crater but a significantly larger structure: it forms when a volcano ejects so much magma that the Earth's surface above the emptied chamber subsides inward. Calderas can reach several tens of kilometers in diameter. Underwater calderas are dangerous: they can generate tsunamis, shock waves, and ash emissions — as demonstrated by the eruption of Hunga Tonga–Hunga Haʻapai in 2022.

Previously, fewer than 30 such structures had been documented underwater. Volcanologist Andrea Verolino from Paris-Saclay University adapted an algorithm originally designed to search for impact craters on Mars and applied it to bathymetric maps — maps of the seafloor topography.

The program initially produced 87,435 candidates. After applying filters and manual verification, 78 suspected calderas remained. Five of them were already listed in existing catalogs, confirming the method's reliability — yielding a total of 73 new objects.

Of the 73 discovered structures, 61 are located not at tectonic plate boundaries but in interior zones — in seamount chains. Nine were identified in volcanic arcs, and eight on mid-ocean ridges.

The authors specifically highlighted seven calderas whose location and shape require priority investigation from the standpoint of volcanic hazard. The ultimate goal of the program is to create a complete global catalog of underwater calderas to improve tsunami early warning systems.