How many magnitude 5 or greater earthquakes happen each year?

How to get close to this number

Earthquake frequency follows a power law, and that is the whole tool here. Each step up in magnitude makes events roughly ten times rarer. If very large earthquakes happen a handful of times a year, then events two magnitude steps smaller happen a hundred times more often — which gets you to the answer from a single anchor.

The full distribution in the explanation shows the law in action: hundreds of thousands detected annually, around a hundred thousand felt, and only about fifteen hundred at magnitude five or above. Instruments detect vastly more than people notice, so a count of earthquakes depends entirely on where the threshold sits.

That also explains why earthquakes feel more frequent than they used to. Detection networks have expanded enormously, so more events are recorded and reported — while the actual rate is essentially constant on human timescales. A rising count in a hazard statistic is very often a story about instrumentation rather than about the Earth.