China fears Scientists warn volcano extinct for 500,000 years 'appears to be recharging'.



China fears Scientists warn volcano extinct for 500,000 years 'appears to be recharging'.

CHINA could face a huge natural disaster in the future after scientists
warned a volcano - thought to be extinct - "appears to be recharging"
after discovering two magma chambers deep below the surface.
Scientists from the University of Science and Technology of China were
studying the Weishan volcano – located inside Wudalianchi volcanic field of
the northeast of the country. This volcano last erupted around 500,000 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, but a study led by Ji Gao – published
in the journal Geology last month – says there may be activity taking place
under Weishan.
The team created a 3D map showing the structure beneath, apparently
identifying two magma pockets.
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, but researchers have warned greater monitoring must now be
introduced.
They also fear that a number of earthquakes reported in the region since 2008
could indicate the movement of magma – a signal that an eruption could be on
the way.
The study reads: "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.

“Therefore, it needs more active monitoring for better forecasting of its
potential future eruptions.”
Prior to the discovery, geologists have kept their focus on Changbai, or also
known as Paektu Mountain, to the south.
This volcano erupted in 946 AD and is deemed one of the most powerful
volcanic events on record – the fallout zone stretched from Japan to
Greenland.
However, other experts not involved with the study are skeptical about the
findings.
Xu Jiandong, director of the volcanic research division at the China
Earthquake Administration in Beijing, told South China Morning Post: “If there
really are huge magma chambers in the area, we should have detected some
related seismic activities.

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