North Korea’s underground nuclear tests have triggered a chain of seismic events, activating ancient fault lines that stretch towards one of the most dangerous volcanoes on Earth, about 100km (62 miles) away, according to a paper published by the journal Science. The joint Chinese and South Korean study, which appeared on Thursday, found that the five nuclear explosions conducted between 2013 and 2017 at the Punggye-ri test site beneath Mount Mantap fundamentally altered the region’s geological...