Red values indicate the earthquakes occurred in Alaska.
Blue values indicate the earthquakes occurred in California.
Earthquakes Located by the USGS NEIC 1980-1989. Earthquakes Located by the USGS NEIC 1970-1979. As more and more seismographs are installed in the world, more earthquakes can be and have been located. The energy release best indicates the destructive power of an earthquake. Since it is really the energy or strength that knocks down buildings, this is really the more important comparison.