Number of strong earthquakes in the U.S. by state

* The data represents earthquakes of a magnitude range of 3.5 and greater.
Number of strong earthquakes in total: 21,080.
Events in the magnitude range of 3.5 to 4.0 in the Aleutian Islands are not recorded on enough seismograph stations to be located.
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake. In all cases, the magnitude is a base-10 logarithmic scale obtained by calculating the logarithm of the amplitude of waves measured by a seismograph. An earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger and corresponds to an energy release of v1000 ˜ 31.6 times greater than one that measures 4.0.