Seismic intensity is the shaking you experience during an earthquake. Unlike an earthquake's magnitude, which is a measure of the energy released and is the same for all locations, the intensity of shaking you feel depends on your location.
Seismic intensity is controlled by four main factors:
Earthquake intensity (what is felt during an earthquake at any given location) is often mistaken for earthquake magnitude (the instrumentally measured size of that earthquake). This animation describes the main factors that contribute to differing intensities using examples of earthquakes. Produced in collaboration with the U.S. Geological Survey.
The "moment magnitude" scale has replaced the Richter scale for large earthquakes. Scientists have developed far-more sensitive seismometers that, with faster computers, have enabled them to record & interpret a broader spectrum of seismic signals than was possible in the 1930's, when the Richter magnitude was developed. Find out what scientists learn from seismograms.