An active underwater volcano off the coast of Vanuatu’s Epi Island has erupted after days of seismic activity had been recorded in the area, forcing authorities to divert shipping and aircraft.
This comes as the Vanuatu Meterology and Geo-Hazard Department raised the alert status of three of the country’s five active volcanoes to level two or showing signs of major unrest.
In an alert issued on the Vanuatu Meterology and Geo-Hazard Department Facebook page on Wednesday afternoon, the department said latest observations confirmed that the volcanic cone is building up with the continuous ash emissions. With the ongoing phreatic explosions, the release of gases and emissions, they set a 10 kilometre (6.2 miles) danger zone radius.
“People on Epi and surrounding islands are also advised to stay on alert for any large earthquake associated with the ongoing volcanic eruptions that could trigger a possible tsunami,” they said.
According to the U.S. Geological Survey, prior to volcanic eruption occurring, rising magma can deform the area surrounding the cone causing swelling in the ground surface, and there may noticeable steaming or volcanic gas activity along with new or enlarged areas of hot ground.
They also warned that steam-blast eruptions from the volcano can occur with little or no warning as superheated water flashes to steam.
Eruption Big Enough to Trigger Warnings
Submarine senior volcano officer Ricardo William told Radio New Zealand that the eruption was big enough to trigger several warnings.
“The volcano activity increased a little bit to explosions that propelled ash to some 100 kilometres that fall around the submarine volcano,” he said.
“We gave advice to the aviation industry as well as the marinas to stay away from the east of Apia island region.”
A watch alert was also issued for other islands surrounding Api.
Sitting above the Pacific’s arc of seismic faults known as the “Ring of Fire,” Vanuatu is also prone to volcano eruptions and cyclones, and has been ranked by the United Nations University as the world’s most at-risk nation for natural disasters.
Eruption Comes a Year After Tongan Explosion
The volcanic eruption in Vanuatu comes just over a year after a massive underwater volcanic eruption in Tonga unleashed an atmospheric shockwave that radiated out at close to the speed of sound.
The eruption of Tonga’s Hunga Tonga-Hunga Ha’apai volcano and subsequent tsunami on Jan. 15, wiped out an entire village on one of Tonga’s small outer islands and killed at least three people.
According to that study on the Tonga volcanic eruption, published on Sept. 22 in the academic journal Science, the volcanic eruption was so violent that its plume penetrated into the stratosphere, blasting at least 50 teragrams (50 billion kilograms) of water vapor.
The stratosphere is the layer of atmosphere between 8 and 33 miles above the earth’s surface.
“This event raised the amount of water vapor in the developing stratospheric plume by several orders of magnitude and possibly increased the amount of global stratospheric water vapor by more than 5 percent,” the paper reads.
In a NASA study conducted at the agency’s Jet Propulsion Laboratory in Southern California, researchers claim the amount of water vapor released was about 146 teragrams, nearly three times more than the amount cited in the Science study.
NASA said the “enormous” plume of water vapor is the equivalent of more than 58,000 Olympic-sized swimming pools.
“We’ve never seen anything like it,” Luis Millan, an atmospheric scientist at the Jet Propulsion Laboratory, said in the NASA report. He led the study of the water vapor brought on by the Tonga volcanic eruption.
In the past 18 years, only two other volcanic eruptions sent “appreciable amounts” of water vapor to such high altitudes—the 2008 Kasatochi event in Alaska and the 2015 Calbuco eruption in Chile—according to NASA.
Both eruptions were “mere blips” compared to the Tonga volcanic eruption, and the water vapor produced dissipated quickly. Water vapor from the Tonga volcano could remain in the stratosphere for “several years,” NASA said.
Aldgra Fredly contributed to this report.