The seismic waves from the Nepal earthquake were registered 8,000 miles away, all the way in the US – though this is completely normal. The story behind the incredible stations that monitor the world's vibrations is one worth knowing.
Who isn't afraid of being waken abruptly by a shaking building whose roof is caving in? Or a huge tsunami sweeping though your town? Earthquakes are terrifying. But what exactly are they? Why do earthquakes happen?