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International Collaboration Detects Signs of Molten Rock Below Mt. Paektu

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An October 2015 view of Lake Chon, located within the Mt. Paektu caldera. | James Hammond

In one of the first scientific collaborations between the Democratic People's Republic of Korea (North Korea) and the West, scientists have seismically imaged the crust beneath Mt. Paektu, an enigmatic volcano straddling North Korea and China.

"It has been exciting to be part of this unique collaboration over the last four years. Through the mutual trust established between both sides, we are beginning to understand the magmatic plumbing system beneath Mt. Paektu," said James Hammond, a lecturer in geophysics at University of London and co-author of the study.

The monitoring and research project on the volcano is supported in part by a grant to AAAS from the Richard Lounsbery Foundation in Washington, D.C., which has helped cover the costs of station construction, maintenance, and logistics. The latest study from the project is published in the 15 April issue of Science Advances.

"Volcanic eruptions, particularly those from volcanoes the size of Mt. Paektu, can have impacts far beyond their immediate surroundings. With increasing development and globalization, our vulnerability to volcanic hazards is increasing. Therefore, we must give attention to understanding volcanoes, no matter where they are," Hammond said.

The new findings, which represent the first estimates of crustal structure on the North Korean side of the volcano (known as Changbaishan in China), may help to explain what caused Mt. Paektu to spew lava in 946 A.D., during what is now recognized as one of the largest historical eruptions in the global record. They may also explain an episode of volcanic unrest observed in the region between 2002 and 2005.

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The international monitoring project has placed new seismometers on Mt. Paektu, located on the border between North Korea and China. | Kosima Weber Liu

International attention turned toward Mt. Paektu during the early 2000s, after North Korean and Chinese scientists noticed increases in seismicity there. However, the details of the structure beneath the volcano, as well as magmatic evolution there, remain poorly understood.

Using data from six seismic stations located in North Korea, Ri Kyong Song at the Earthquake Administration in Pyongyang, Democratic People's Republic of Korea, along with Hammond and colleagues, obtained readings revealing that a large region of the crust has been modified by magmatism associated with volcanism.

Based on their results, the authors suggest that a region of molten rock is likely to be present throughout a significant portion of the crust below the volcano. This region of melt may represent a potential source for the magmas that erupted in the historical period and may be associated with the more recent seismic unrest.

The researchers' results are based on application of the receiver function method, which measures energy from distant earthquakes interacting with the Earth beneath a volcano. This in turn reveals information about volcanic crust thickness and rock composition. The results of Song and colleagues indicate that the crust beneath Mt. Paektu is more complicated than previously assumed, and has likely been modified by the 3.5 million-year history of volcanism in the region.

Author

Nadia Ramlagan