Underwater volcanic eruptions are barely seen, but their aftermaths tell the tale of some truly spectacular fireworks. Back in 2012, for example, a submerged fiery fountain emitted the equivalent of seven Manhattan’s-worth of volcanic debris in less than a day, which was first spotted not in person, but from space.
Now, as highlighted by a brand-new study by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), along with the Universities of Aberdeen and Adelaide – two institutions a geographical world apart – underwater lava flows, when mapped, can look extremely surreal too.
Although the paper itself isn’t brave enough to make the comparison, the team’s press release suggests that this submerged hellscape looks a lot like “Mordor-under-the-sea,” which sounds like a much-needed mashup of Lord of the Rings and The Little Mermaid. To be fair, though, the maps you’ll find in Lord of the Rings do look a lot like these new works of volcanic cartography.
In order to make these rather aesthetically pleasing maps, the international team of geophysicists beamed seismic signals from a boat down to the seafloor. Seismic waves reflect and travel through objects differently depending on what they’re made of, and using this information, complex, 3D pictures of otherwise obscured landscapes can be created.
In a way, it’s like creating a painting using seismic waves.
So what have CSIRO and co. actually mapped? Well, they were sailing over the Bight Basin Igneous Complex (BBIC), a 120-kilometer (81-mile) long site of volcanism off the coast of southern Australia dating back to the middle of the Eocene epoch, between 56 and 34 million years ago.
The team found 26 buried lava flows, associated with volcanoes both tall and small. They range in length from 0.5 kilometers (0.31 miles) to a whopping 34 kilometers (21 miles), and their structure appears to suggest that they were erupted offshore in water depths of around 300 meters (984 feet).
As reported in the journal Geochemistry, Geophysics, Geosystems, all of these frozen flows exhibit a range of curious features. Their anastomosing nature has surrounded older bits of the now-buried seafloor, creating islands of land gloriously named “kipukas”.