How many earthquakes have happened since 1900?
Hundreds of millions.
The total earthquakes worldwide since 1900 can very well reach hundreds of millions. This is based on the U.S. Geologic Survey estimate stating that several million earthquakes occur annually in the world. The largest recorded earthquake in the world occurred in Chile on May 22, 1960 with a magnitude of 9.5. The deadliest earthquake occurred on December 26, 2004 off the West Coast of Northern Sumatra, Indonesia with 227,998 fatalities.