NASA's Landsat 9, an earth observation satellite launched in September last year, has captured the eruption of the Kavachi undersea volcano in the Solomon Islands in the Pacific Ocean, the space agency said on its website.
The Landsat program is one of the longest-running enterprises for acquiring imagery of the Earth. A collaboration with NASA and the United States Geological Survey (USGS), the Landsat program began in 1972 and has been regularly updated to capture high-quality images of Earth. Landsat 9 is equipped with two remote sensors, an operational land imager (OLI) and a thermal infrared sensor (TIRS). The nearly 6,000-pound (2,721 kg) satellite entered service in January this year and has sent back images of an eruption of an undersea volcano.
What are undersea volcanoes?
An undersea or submarine volcano is a fissure on the Earth's surface from which magma can erupt. Usually located near tectonic plates, these volcanoes account for 75 percent of the magma output of the planet. Apart from spewing out contents from inside the earth that form new landmasses, these volcanoes can also be a force that can change our world forever.
Earlier this year, an underground eruption near the island of Tonga was found to be 500 times more powerful than the nuclear explosion in Hiroshima, sent tsunami warnings to scores of nations in the area, and cut off the island nation from the rest of the world for many days.
Geologists and oceanographers are keen to study these volcanoes since they provide insights into the Earth's interiors and the short-lived islands they create from time to time.
What is the 'Sharkcano'?
Since its first recorded eruption in 1939, the Kavachi volcano in the Solomon Islands has created many such islands. Barely half a mile (1 km) long, these islands have been swept away by waves in the area. The base of the volcano lies at a depth of 0.75 miles (1.2 km) while its summit is just 65 feet (20 m) below sea level.
Located barely 15 miles (24 km) from the habituated Vangunu Islands, the volcano has been reported to have erupted violently in 2007 and then in 2014 with residents reporting ash and steam eruptions from the site.
The volcano entered an eruptive phase in October last year and previous studies of the region have shown the volcano's lava can be basaltic, meaning it is rich in magnesium and iron while also being andesitic, which means containing more silica, the NASA website states.
Even with large differences in its eruptions that make the water superheated, acidic, and containing volcanic rock fragments, a scientific expedition in 2015 found two varieties of hammerhead sharks near the volcano's crater, giving it the nickname 'Sharkcano'. High amounts of sulfur emitted by this volcano haven't stopped microbial communities from thriving here as well as piquing the interest of ecologists.
Geologists have used a wide variety of instruments to pick up early signals of volcanic eruptions. However, as Matthew Blackett, an expert on Physical Geography and Natural Hazards at Coventry University in the U.K. notes in a post on Conversation, the best way to predict undersea volcanoes is through satellite images. Blackett goes on to say that ocean color changes have been spotted almost a month before undersea volcanic eruptions.
So, while Landsat 9 might have brought us an image of an eruption, it is doing the valuable job of keeping an eye on where the next eruption might take place as well.