NOAA Says 28.7% of Global Seafloor Is Mapped, Leaving 71.3% Still Uncharted

3 articles · Updated · spacedaily.com · Jul 17

28.7% of the global seafloor had been mapped with modern high-resolution tools by April 2026, NOAA said, underscoring how much of Earth’s underwater terrain remains poorly charted.
NOAA’s figure extends a steady rise from 6.2% in 2014 to 26.1% by 2024, but explorers have directly seen less than 0.001% of the deep seafloor.
Much of that hidden landscape includes the mid-ocean ridge — a roughly 65,000-kilometer volcanic chain that NOAA calls Earth’s longest mountain range, with more than 90% underwater.
Marie Tharp’s 1957 Atlantic map and 1977 world seafloor map helped reveal the ridge’s central rift and support plate tectonics, showing how limited data can still transform understanding of the planet.

Sources

If one woman's map revealed a hidden world, what will mapping the final 70% of the seafloor uncover about our planet?

Why does Earth’s longest mountain range remain less mapped than the surface of Mars, despite shaping our continents?