Because they're so magnetized, stress accumulates below the surface of these strange objects. Every so often, this stress becomes too much for the crust of the neutron star to take, and - crack! The crust ruptures, causing a starquake.
Neutron stars are weird, wonderful, and extreme objects. The remnant cores of dead stars, they're typically at least twice as massive as our entire solar system - with all of that mass packed into an object with a radius of just 10 miles. To give some idea of exactly how powerful the forces behind starquakes are, the crust on a neutron star is expected to be about 10 billion times stronger than steel!
When these crust fractures happen, they send out a blast of high energy x-rays and gamma rays. Known as megaflares, these starquakes are responsible for some of the mysterious gamma ray bursts observed throughout the Universe.
Stellar Post Mortem To gain a better idea of what they were looking at, researchers made a model of how neutron stars cool with age, as well as the way their magnetic fields decay. They estimated that SGR 0418 is over half a million years old.