https://www.newscientist.com/article/2146148-seismic-tests-hint-north-koreas-nuke-is-its-first-hydrogen-bomb/ > “The nuclear explosion was seen around the world – the surface waves generated really do cover the globe,” says Steven Gibbons, senior research geophysicist at Norwegian monitoring agency NORSAR, which combines data from its own sensors with that of other institutions. > The rumbling was even registered by a seismometer set up by a school in Nottingham, England.