1) The world’s largest earthquake with an instrumentally documented magnitude occurred on May 22, 1960 near Valdivia, in southern Chile.

2) The largest earthquake to hit the U.S. was on March 28, 1964, when a 9.2 magnitudequake struck Prince William Sound in Alaska.

3) It is estimated that there are 500,000 detectable earthquakes in the world each year. 100,000 of those can be felt, and 100 of them cause damage

4) Each year the southern California area has about 10,000 earthquakes. Most of them are so small that they are not felt. 

5) There are several thrust faults that stretch from Arkansas to Illinois.

Collectively they are known as the New Madrid Seismic Zone or New Madrid Fault Line.

It is a source of intraplate earthquakes or earthquake within a tectonic plate.

6) It lists Florida and North Dakota as the two states with the fewest earthquakes. Alaska is known to have the most earthquakes.

7) If an earthquake has not been very strong or we are reasonably far away from its center we will not at all sensethe P-waves as an earthquake but onlyhear the sound induced by them in the air. Still, we may feel the S-waves quite clearly and then other waves which often arrive later, especially at a distance.