As the Earth rotates on its axis and orbits the Sun, the Sun orbits the center of the Milky Way at a rate of 800,000 kilometers (500,000 mi) per hour. It’s dizzying how remarkable the universe has remained since its inception. Earth is a tiny piece of a much larger puzzle, and yet, its composition and inner workings are still extraordinary.
The quakes that can be felt—but cause little to no damage—occur around 55,000 times annually. You might not realize what’s happening right under your feet. Moderate to great earthquakes (5.0–8.9 on the Richter scale) do cause damage. They occur nearly 1,000 times per year.
The stronger earthquakes occur less frequently, of course, but the injury and fatality rate for those is much higher. Extreme earthquakes are the rarest kind documented. They occur once every 20 years or so, registering 9.0–9.9 on the Richter scale.