Earth from space: Erupting 'sharkcano' spits out a giant underwater plume in Oceania

This unusual image shows a large plume of discolored water rising toward the Pacific Ocean's surface from the Kavachi volcano, also known as "sharkcano," during an undersea eruption.

Kavachi is a submarine volcano that is part of the Solomon Islands, around 15 miles (24 kilometers) south of Vangunu Island. Its peak stands roughly 3,600 feet (1,100 meters) above the seafloor and lies just 65 feet (20 m) below the waves. The volcano is named after the sea god of the Vangunu people and is also referred to as "Rejo te Kvachi," or "Kavachi’s Oven," according to NASA's Earth Observatory.

In 2015, a research expedition discovered multiple scalloped hammerhead sharks (Sphyrna lewini) and silky sharks (Carcharhinus falciformis) living within the volcano's central crater. The surprising presence of the oceanic predators at the volcano raised "new questions about the ecology of active submarine volcanoes and the extreme environments in which large marine animals exist," the researchers wrote.

It is unclear whether any of the sharks at Kavachi were hurt by the outburst that triggered the plume in the image or if they were able to sense the incoming eruption and evacuate the crater.

The image was first released in May 2022 by NASA Goddard on the social media platform X along with the caption: "You’ve heard of sharknado, now get ready for sharkcano."

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The plume in the photo is part of an eruption that began in October 2021 and lasted for just a few weeks after the aerial image was taken. Similar plumes occurred during subsequent eruptions in August 2023 and April 2024, according to the Global Volcanism Program at the Smithsonian's National Museum of Natural History.

Before then, the volcano's most recent major eruptions were in 2016, 2014, 2007 and 2003. In the past, researchers also sighted ephemeral islands up to half a mile (1 km) wide being birthed by the eruptions and then sinking. A similar ghostly landmass recently emerged after an undersea volcano in Japan blew its top in 2023.

Explosive plumes

Kavachi experiences "phreatomagmatic eruptions," which occur when magma meets water and ejects steam, ash, volcanic rock fragments and chunks of magma known as "incandescent bombs," according to the Earth Observatory.

A study conducted in the wake of the 2007 eruption found that the volcanic plumes are made of warm, acidic water that also contains particulate matter and sulfur, which "attracts microbial communities that thrive on [the chemicals]," the researchers wrote.

The volcano can also launch jets of heated water without any visible plumes or other signs of erupting.

Residents of neighboring islands have frequently reported that they regularly see steam and ash on the water's surface between eruptions, further confirming that the so-called sharkcano is percolating beneath the surface.