Supervolcanoes located in clusters
The world includes six groups of a total of 27 supervolcanoes, which could cause eruptions with global consequences. Unlike smaller volcanoes, they often lack the distinctive coneshape. That is due to the fact that they have blown themselves to bits and pieces. exploding at the same time” and probably the most severe that the world had seen in 2,000+ years. The eruption eliminated the entire mountain peak, leaving a hole with a four kilometre diameter, which is now called Heaven Lake. A thick layer of volcanic ash was spread across an area of 1.5 million km2, reaching as far as Japan 1,000+ km away. Even in Greenlandic ice core drillings 7,000 km away, you can see evidence of Mount Paektu’s ash.
Closer to the volcano, the eruption was a maelstrom of fire, rock, gas and ash, which eliminated all life. In a 40 km radius around Mount Paektu, the layer of slag, ash, and hardened lava averages eight metres thick, and in hollows in the terrain, the thickness of the layer is 70-80 m. It is the remains of glowing avalanches, which, according to the scientists’ calculations, flowed down the volcano at speeds of up to 600 km/h. Glowing avalanches occur, when an eruption is briefly losing momentum – perhaps only for a few hours. When it happens, the energy source that keeps the 25-30-km-high eruption column of magma drops, ash, and volcanic gases in the air is turned off. The column collapses, falling towards the cone, and continuing down the sides and further across the landscape as a 400-degree-hot avalanche.
Seismographs monitor the volcano
Hammond and Oppenheimer’s stay has exc eeded all expectations, and the scientists install seismographs or earthquake meters, which they use for passive seismic tomography purposes. The method takes advantage of earthquake vibrations spread through the ground like 3D ripples in a pond.
Around the volcano, minor earthquakes constantly occur, sending microscopic vibrations in all directions. The type of
rock determines, how fast the vibrations travel to reach the seismic monitoring stations. The seismographs record all motion in Earth’s crust, saving the data, and after about two years of measurements, they can be united into a 3D image of what is going on under the volcano, providing us with an idea of how imminent the next eruption is.
Climate change could reach Europe
An eruption such as Mount Paektu’s in 946 AD sends large quantities of climatechanging chemicals into the atmosphere. Historic sources from East Asia describe, how the weather was markedly colder during the years following the eruption with snow in the summer and thick ice on the lakes.
Luckily for the rest of the world, the eruption was in early winter, when the climate effect of a volcano with Paektu’s geographical location remains local instead of spreading to the entire Northern Hemisphere. If the eruption had taken place in the spring or summer, when winds spread fine particles more efficiently, the effect could have been much more marked – also in Europe.
The Indonesian Tambora volcano showed how such chemicals can spread on a global scale in 1815. An eruption of the same dimensions as Mount Paektu’s made temperatures fall markedly in many parts of the world, resulting in the famous "year without a summer" in 1816.
Today, a similar eruption would have much more severe consequences, reducing the production of grain such as wheat and rice from the world’s breadbaskets in Europe, the US, and China by 75%. Global food production would collapse, billions could starve, and our civilisation would be put to a serious test.
Faimine is, however, the least of North Korea's worries. In case of an eruption like the one in 946 AD, the entire northern part of the country would be buried in lava and the rest smothered under massive quantities of ash, ruling out any relief and feeding of survivors.
It is probably bearing such a destructive disaster in mind that the government in Pyongyang has begun to take an interest in Mount Paektu. Worries grew in 20022005, as the volcano became ever more active. The ground rose, gas leaks became more frequent, and earthquakes in the area became
Seismographs registered North Korea's most recent nuclear testing in September 2017. The artificial earthquakes were up to 6.3 Richter.
more powerful. The danger signals finally made North Korea reach out to the outside world and the two British geologists.
Paektu is ready for its next eruption
Hammond and Oppenheimer’s work showed that the active magma chamber reaches at least 35 km into the ground, which is unusually deep. The same conclusion has been reached by Chinese scientists, who estimate that the unstable period in 2002-2005 was due to the fact that magma flowed up into the magma chamber from deep below.
Previous studies have also shown that the magma is only very briefly in Mount Paektu’s magma chamber, before the volcano starts to erupt. Moreover, Paektu is a sensitive volcano, in which minor exterior influences could trigger an eruption. The eruption in 946 probably began, when small quantities of easy-flowing magma arrived to the bottom of the magma chamber.
In 2012, scientists even concluded that the next major eruption would naturally come in the next few decades. In other words, the volcano is ready to pop.
Testing speeds up eruption
Though the relationship between the British geologists and their North Korean colleagues is improving, they are constantly challenged by political tension.
The project has to use mostly North Korean or Chinese technology, because international sanctions against the country prevents the foreign scientists from bringing sophisticated equipment. One of the tools that Hammond and Oppenheimer would like to use measures microscopic variation in Earth’s magnetic field. However, the method is too much like the equipment that ships and planes use to detect submarines, so they are not allowed to bring it.
The highly Communist government is an enemy of about all other nations in the world, so the poor and starved country spends huge resources on its military and not least its nuclear arms programme, which has so far carried out six successful underground test explosions of still more powerful bombs.
A nuclear bomb, which detonates under the ground, is not by far innocent in a geological perspective. The explosion sends shock waves in all directions, and as Mount Paektu is just 100 km from the test site, the volcano very much feels the artificial, but powerful earthquakes of magnitudes of 6+ Richter.
So, the underground test explosions make up a direct menace to Paektu, four American and South Korean geologists concluded in 2016.
The problem arises, because the vibrations cause pressure changes in the magma chamber. Pressure changes can make dissolved gases change state and produce air bubbles like the carbon dioxide of sodapop. In a state of bubbles, gas takes up much more space than when it is dissolved, increasing the pressure in the magma chamber explosively – perhaps even enough to kickstart an eruption.
In 2017, Hammond and Oppenheimer visited North Korea for the ninth time to study Mount Paektu, but also to celebrate that the first scientific articles about the exceptional cooperation have been published in international journals; a cooperation that contributes slightly to improving difficult international relations that diplomats have almost given up on.
There might be good new though. Reports in April 2018, after North Korea's sixth test, suggest the underground site suffered collapse and cannot be used anymore.