Sharkcano, an undersea volcano where sharks live
This story was making the rounds on social media yesterday (May 25, 2022). Researchers have dubbed the underwater Kavachi volcano a sharkcano after finding sharks living in its submerged crater. The Kavachi sharkcano lies in the waters off the Solomon Islands, in the ocean near Australia and Papua New Guinea. Kavachi began an eruptive phase in October 2021, and satellite data showed discolored water around Kavachi on several days in April and May 2022, indicating eruptive activity. NASA Earth Observatory shared the satellite image, showing discolored waters rising upward from Kavachi on May 14.
The last large eruptions at Kavachi occurred in 2014 and 2007, though the volcano erupts nearly continuously. Nearby residents often report seeing steam and ash.
Researchers said that finding the sharks living in the volcano’s crater raised:
… new questions about the ecology of active submarine volcanoes and the extreme environments in which large marine animals can exist.
What’s going on inside the sharkcano?
Scientists found two species of sharks, including hammerheads, living in the submerged crater during a scientific expedition to Kavachi in 2015. Submarine plumes of superheated, acidic water, such as the one from Kavachi, usually contain particulate matter, volcanic rock fragments and sulfur. The scientists also found microbial communities thriving on the sulfur.
— California Academy of Sciences (@calacademy) July 13, 2015
Landsat 9 image of the underwater volcano
The Landsat 9 satellite took these images of activity from the submarine volcano. In the image, you can see the volcano emitting a plume of discolored water. From the wider-view image below, you can see that Kavachi lies 15 miles (24 kilometers) south of Vangunu Island.
This region around the Solomon Islands is an active area near a subduction zone, where two plates come together.
The summit of Kavachi currently lies about 65 feet (20 meters) below sea level. The base of the volcano sits on the seafloor at a depth of about 3/4 of a mile (1.2 kilometers).
Kavachi sharkcano, and other names
The island gets its name from the Gatokae and Vangunu peoples name for a god of the sea. People also sometimes call it Rejo te Kvachi, or Kavachi’s Oven.
Whatever you call it, the underwater volcano is a busy, active spot. It creates new, temporary islands, up to a half mile (1 km) long. But soon the waves erode the new land, taking it back down under the sea.
NASA said that:
The volcano produces lavas that range from basaltic, which is rich in magnesium and iron, to andesitic, which contains more silica. It is known for having phreatomagmatic eruptions in which the interaction of magma and water cause explosive eruptions that eject steam, ash, volcanic rock fragments and incandescent bombs.
Bottom line: The underwater Kavachi volcano in the Solomon Islands is being called a sharkcano because scientists found sharks living in the superheated waters inside the volcano.