An interesting question came up in a discussion about earthquakes recently – namely, could one ever be powerful enough to fracture the planet, or even completely break it apart? This is a surprisingly difficult question to answer, but let's take a look at the science to see how possible this type of apocalypse really is. First off, let's just remind ourselves what causes an earthquake and just how ludicrously energetic they are at their worst. There are so many different ways to get earthquakes – even the Moon's gravitational pull can trigger them, for goodness' sake – but for the sake of simplicity, we'll stick to the most common for now. You've got fault networks like the San Andreas complex, which has formed at the point where the Pacific Plate is moving northwards with respect to the North American Plate. This type of tectonic margin is called a "transform" boundary, and it tends to produce very shallow and damaging earthquakes. Then you've got two plates coming together to collide