Comment: 10:35  11:20 (00:45)
Source: Annenberg/CPB Resources  Earth Revealed  9. Earthquakes
Keywords: "Richter Scale", magnitude, earthquake, "elastic energy", energy

Our transcription: The scale that Richter devised runs from magnitude minus 2 to infinity although seismologists believe that rocks can at most only store elastic energy equivalent to magnitude 9 before they snap. The smallest tremors that can be discerned by humans feeling like the rumbling of a passing train measure about 2.5 on the Richter Scale. A magnitude of 4 is equivalent to the amount of energy released by 1,000 tons of explosives. A magnitude just above 8 represents about as much energy as produced by 200 one megaton nuclear bombs. The reason for the huge jumps in energy between one unit and the next on the Richter Scale is that each unit of magnitude increases logarithmically by a factor of just over 30 times more energy released.

Geology School Keywords
