Understanding how a moon or planet works below the surface or deep in its oceans isn’t just for icy moons. We are still trying to understand how Earth works! Unlike how scientists tracked the magma flow under Iceland using seismic data, basically predicting the ongoing eruption we are all still enjoying on YouTube, it’s very difficult to get seismic monitors to the ocean floor. It’s not impossible. But the ocean is vast and deep, making the placement of instruments expensive and time-consuming. So one scientist looked for another method to add to the toolbox, something we can use that is already in place. In this case, satellite imagery. 

In a new study in the journal Water, Yuji Sakuno has suggested using satellite images of sea discoloration as a new predictor of an impending underwater volcanic eruption. Volcanoes release different chemicals as they erupt, as part of the gas and minerals trapped in the magma. These chemicals can then change the color of the water. For example, iron can turn the water more yellow or brown; aluminum creates white splotches in the water. Sakuno examined images captured in 2020 around an island in Japan that erupted and was able to find changes in the seawater that occurred a month before the eruption started. 

This is just one volcanic eruption and one data set, but that means we can test the experiment with other eruptions and other satellite images, and maybe we have found a new, better predictor of underwater volcanic eruptions.

More Information

Hiroshima University press release

“Trial of Chemical Composition Estimation Related to Submarine Volcano Activity Using Discolored Seawater Color Data Obtained from GCOM-C SGLI. A Case Study of Nishinoshima Island, Japan, in 2020,” Yuji Sakuno, 2021 April 16, Water