Shown are the locations of the two strongest earthquakes ever record in theUnited States. At 9.2, the one that shook Alaska in 1964 was by far the mostviolent. However, the Great San Francisco Earthquake in 1906 did the mostdamage and took the most lives. The obvious reason is that it struck a verypopulated area, while the Alaskan quake did not.The most powerful earthquake ever recorded was the 9.5 monster that hit Chilein 1960. That quake produced deadly tidal waves that reached as far away asJapan.

The scale used to rank the destructive power of earthquakes is exponential.

Simplifying things a bit, a magnitude 6.0 quake releases 10 times more energythan a magnitude 5.0, and a magnitude 7.0 quake is roughly 100 times aspowerful as a 5.0.

On average 18 major earthquakes (7.0 to 7.9) occur on the planet each year.

Great quakes between 8.0 and 8.9 are much more rare on average occurring onlyonce each year. An incredible earthquake of magnitude of 9.0 or stronger mayoccur only once in 20 years.

Story by AccuWeather.com Senior Meteorologist John Kocet.