* Astronomy

Volcanic sleeping giant opens North Korean co-operation

Scientists from the UK, US and North Korea have joined forces to monitor the volcano responsible for one of the largest eruptions in history.
The volcano straddles the border between North Korea and China, and has been largely dormant since erupting a little over a thousand years ago.
Despite being at the top of the list of big eruptions, Mount Paektu remains obscure and enigmatic.
Details of the collaborative effort have been outlined in Science journal.
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Title: Recent unrest of Changbaishan volcano, northeast China: A precursor of a future eruption? 
Authors: Jiandong Xu, Guoming Liu, Jianping Wu, Yuehong Ming, Qingliang Wang, Duxin Cui, Zhiguan Shangguan, Bo Pan, Xudong Lin, Junqing Liu 

Over 12 years of continuous monitoring of Changbaishan volcano in the border region of China and North Korea by means of volcanic seismicity, ground deformation, and volcanic gas geochemistry yields new evidence for magmatic unrest of the volcano between 2002 and 2006. In this so-called "active period," the frequency of volcanic earthquakes increased by about 2 orders of magnitude compared to that of the background "inactive periods." The active period was also accompanied by ground inflation, high values of CO2, He, H2, and high ratios of N2/O2 and 3He/4He in volcanic gases released from three hot springs near the caldera rim. The monitoring evidence implies pressurisation of the magma chamber, possibly caused by incremental magma recharge. The ground deformation data from both GPS and precise levelling are modelled to suggest the corresponding deformation source is at 2-60 km depth beneath the volcano's summit, where earthquake swarms were detected in 2002 and 2003. Our findings suggest that the magma chamber beneath Changbaishan volcano has awakened and resumed activity after remaining dormant since AD 1903. There is an urgent need to keep close watch on this active and very hazardous volcano in northeast China. 

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