Radar satellite data reveals 19,000 previously unknown undersea volcanoes

A team of oceanographers at Scripps Institution of Oceanography, in collaboration with a colleague from Chungnam National University and another from the University of Hawaii, has mapped 19,000 previously unknown undersea volcanoes in the world’s oceans using radar satellite data. In their paper published in the journal earth and space sciences, The group describes how they used radar satellite data to measure seawater ridges to find and map undersea volcanoes, and explains why doing so is important.

The ocean floor, like dry land masses, has a wide range of terrain. As with dry land, the features that really stand out are the mountains, and in the ocean they are called seamounts. As on Earth, they can be created by tectonic plates pushing against each other, or by volcanic eruptions. Currently, only a quarter of the seafloor has been mapped, meaning no one knows how many seamounts there are, or where they might be. This can be a problem for submarines, as US submarines have twice collided with seamounts, putting these vehicles and their crews at risk. But not knowing where seamounts are located is another problem. It prevents oceanographers from creating models that depict the flow of ocean water around the world.

In this new effort, the research team set themselves the task of discovering and mapping as many seamounts as possible, and to do so, they used data from radar satellites. Of course, such satellites cannot see seamounts, and instead measure the height of the sea surface, which changes due to changes in the force of gravity associated with the topography of the sea floor; The effect is known as the sea hill. In doing so, they found 19,000 previously unknown seamounts.

The team points out in its paper that other important reasons for mapping the ocean floor include things like aiding seafloor mining efforts, where seamounts contain vast amounts of rare earth minerals. More complete seamount maps would also help geologists better map the planet’s tectonic plates and geomagnetic field. Some seamounts also provide habitat for a wide range of marine life.

But more importantly, it has a very strong influence on deep-sea ocean flow. When currents flow into seamounts, they are pushed up, carrying cold water with them, and mixing in unknown ways. Mapping these currents has become more important as oceans absorb more heat and carbon dioxide from the atmosphere and fresh water dissolves, due to ongoing climate change.