Radar satellite data reveals 19,000 previously unknown undersea volcanoes

A team of oceanographers at the Scripps Institution of Oceanography, working with a colleague from Chungnam National University and another from the University of Hawaii, have 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 mounds to find and map undersea volcanoes and explains why doing so is important.

The ocean floor, like dry land masses, is characterized by a variety of topography. As with land, the features that really stand out are the mountains – in the ocean they are called seamounts. And just like on Earth, it can be formed by tectonic plates pushing against one another, or by volcanic eruptions. Currently, only a quarter of the sea floor has been mapped, which means no one knows how many seamounts there are, or where they might be. This could be a problem for submarines – twice US submarines have hit seamounts, endangering these vehicles and their crews. But not knowing where the seamounts are is another problem. Oceanographers create 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. Such satellites cannot see seamounts, of course, and instead measure the height of the sea surface, which changes due to changes in gravity associated with the topography of the sea floor; An effect known as sea ridge. In doing so, they found 19,000 previously unknown seamounts.

Other important reasons for mapping the ocean floor, the team notes in their paper, include things like helping with seafloor mining efforts — seamounts contain huge amounts of rare-earth minerals. More complete seamount maps will also help geologists better map the planet’s tectonic plates and geomagnetic field. Some seamounts also provide a home to a wide variety of marine life.

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