How does the Richter Scale work?

The Richter Scale, contrary to popular perception, is actually just derived for California. It's a measurement based on the displacement measured on a seismograph. This measures the displacement of the Earth due to ground motion. It's an empirical measure, and also logarithmic. If you take a magnitude 5 and a magnitude 6 earthquake, the magnitude 6 will be bigger in terms of energy release than a magnitude 5. But a magnitude 7 will be roughly 1000 times bigger than a magnitude 5.