The Question:

How big does an earthquake have to be to be considered "major" and how many major earthquakes happen each year?

The Answer:

For an earthquake to be considered "major" it must have a magnitude between 7 and 7.9.

According to the National Earthquake Information Center, 18 major earthquakes occur each year around the world.

Here is a link to a chart of the Frequency of Earthquakes Worldwide.

—The Fact Monster