The world's strongest earthquake (with an instrumentally documented magnitude) occurred on May 22, 1960 near Valdivia, in southern Chile. It was assigned a magnitude of 9.5 by the United States Geological Survey. It is referred to as the
"Great Chilean Earthquake" and the
"1960 Valdivia Earthquake". The earthquake occurred on a fault that is almost 1,000 miles long. A
"mega-quake" in its own right.
California is often referred to as "earthquake country" with dozens of minor earthquakes occurring every week. The San Andreas fault is only 800 miles long, so it has been said an 8+ would be unlikely in California. No fault long enough to generate a magnitude 10 earthquake is known to exist. If it did, it would extend around most of the planet. However, if a large celestial object were to crash into Earth, a 10+ "earthquake" could certainly occur that way. While there can be no official ceiling on the possible magnitude of an earthquake, no magnitude 10 (or greater) earthquake has ever been observed.
The 6 strongest earthquakes ever recorded:
m9.5 - Valdivia, Chile, 22 May 1960
m9.2 - Prince William Sound, Alaska, 28 March 1964
m9.1 - Sumatra, Indonesia, 26 December 2004
m9.0 - Sendai, Japan, 11 March 2011
m9.0 - Kamchatka, Russia, 4 November 1952
m8.8 - Bio-bio, Chile, 27 February 2010
