Earthquake Facts

  • A magnitude 7.2 earthquake produces 10 times more ground motion than a magnitude 6.2 earthquake, but it releases about 32 times more energy.  It is the energy released that best indicates the destructive power of an earthquake.
  • A magnitude 9.7 earthquake produces 794 times more ground motion than a 6.8 quake as measured on seismograms, but the 9.7 quake releases 23,000 times more energy than the 6.8.  This explains why big quakes are so much more devastating than small ones.  The amplitude (size) differences can be big, but it is the energy (strength) differences that are huge and do the tremendous damage.
  • The most earthquakes recorded in the past decade were of a magnitude of 3.0 to 4.9.  More earthquakes fall into the 4.0 to 4.9 magnitude worldwide while most of the United States earthquakes fall into the 3.0 to 3.9 magnitude range.
  • There were 70,897 earthquakes of 4.0 to 4.9 magnitude worldwide during the past decade while in the United States there were 3,952 of that magnitude.
  • Estimated deaths from the earthquakes in the United States in the past decade was 68, while in the same time period worldwide, there were an estimated 127,198 deaths.
  • 10 of the 15 largest earthquakes in the United States were in Alaska, three were in California, one in Hawaii, and one in Missouri.  The largest one was in Prince William Sound, Alaska on March 28, 1964 with a magnitude of 9.2.
  • During the 20th Century, the largest earthquake in the the world took place in Chile on May 22, 1960 with a magnitude of 9.5.  Of the ten largest in the world since 1900, three took place in Alaska, the others were in Russia, Ecuador, Kuril Islands, India, and another in Chili.

* Information from the US Geological Survey National Earthquake Information Center.