Volcano in China Appears to Be 'Recharging,' Scientists Say

A volcano in China appears to be "recharging," with scientists discovering two magma chambers deep beneath the surface.

Scientists led by Ji Gao, from the University of Science and Technology of China, were studying the Weishan volcano, which sits in the Wudalianchi volcanic field in the northeast of the country. This volcano last erupted around 50,000 years ago, but there have been other, far more recent eruptions in the complex.

The Wudalianchi volcanic field covers around 193 square miles and contains 14 steep-sided cinder cones that are surrounded by lava flows. The last eruption at the site was in 1776.

In a study published in the journal Geology, Gao and colleagues say the volcanoes in this complex seem to erupt sequentially, moving from southwest to north east. This, they say, indicates there may be activity taking place under Weishan.

To better understand what is going on at the volcano, the team created a 3D map showing the structure beneath. Previously, scientists had identified a shallow magma chamber beneath the volcano. In the latest study, the team found this shallow chamber in the upper crust, along with another deeper down, in the middle crust.

Researchers say the findings are consistent with models suggesting the magma in the middle crust may be serving as a source to "recharge the magma chamber in the upper crust."

The team say that based on their analysis the melt fraction of the magma in the chambers beneath the volcano are around 15 percent. Eruptions are generally thought to take place when this figure reaches 40 percent. While Weishan has not reached this threshold, the team say there should be greater monitoring of the volcano.

Researchers also say earthquakes have been recorded at the site since 2008. Seismic activity can indicate the movement of magma, which can be a signal an eruption may be about to take place.

"Considering the significant melt fractions and active earthquakes and tremors occurring around magma reservoirs, the Weishan volcano is likely in an active stage with magma recharging," the team wrote.

James Hammond, from the Department of Earth and Planetary Sciences at Birkbeck, University of London, U.K., who was not involved in the study, told Newsweek the latest findings fit with earlier research on Weishan.

"The fact that these independent studies show the same features adds weight to the conclusions that a significant magma body is present beneath the volcano," he said in an email.

Hammond said the significant melt suggested by the team is a feature seen at many volcanoes around the world, including Paektu Mountain, an active volcano that sits on the border of China and North Korea. "To date, most attention in China has been on [Paektu] as this showed signs of unrest in 2002-2005. However, this suggests other volcanoes in China may also have the potential to erupt and so should be further studied to understand their history and monitored for future activity."

Aerial view of a volcano in the Wudalianchi volcano field. iStock