Less than a quarter of the Earth’s entire ocean floor had been mapped so far. That leaves large gaps in our understanding of the underwater realm. The 20,000 new volcanoes discovered under the sea prove it.
Julia Gevorgian is a scientist at Scripps Oceanographic Institution in California. She leads the team of experts who made the findings. Most are more than 700 meters high. Some rise 2,500 meters above the seafloor.
Probes and satellites
“There may be many more. Current altimetry data have a resolution of about 6 km. It means that seamounts with a diameter of less than 6 km will not be located,” Gevorgian stresses.
Seamounts are created by volcanic activity in the deep ocean. They can reach a height of 3 to 10 km. They are usually easy to detect with ultrasonic radar, but only if a ship passes over them. How do you detect the bumps in the sea? With a traditional echo sounder and data from the European Space Agency’s CryoSat-2 satellite.
The sonar uses sound waves that bounce off the seafloor. The satellite detects small changes in sea surface elevation. And it reflects the gravitational pull of humps in the Earth’s underwater crust. The larger the hump, the stronger its gravitational pull attracts seawater to the top.
Thousands of volcanoes
These 20,000 new volcanoes discovered under the sea are in addition to those already discovered. The number now stands at 43,454, almost double the number we knew. Seamounts channel nutrient-rich water from the depths. They are a haven for marine life traversing desert oceans. Their steep slopes also interfere with ocean currents that carry heat around the world. Researchers hope to find clues about plate tectonics and magmatism, as well as precious rare earth minerals.
“These are important objects for study, mapping, and classification,” Gevorkian write. The information is in their article published in. Earth and Space Science.