The Richter scale |
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Mr Richter's Earthquake magnitude scale is poorly understood. The scale ... 2, 3, 4, ... refers to the movements of a seismograph needle a hundred kilometers or so away from the epicenter of a small Earthquake in California. The scale is extrapolated for large quakes though 6 and 7 up to 9. Each point increase on the scale represents approximately a 35 fold increase in energy released. A quake of magnitude 8 is usually followed by many after shocks of magnitude 6. The after shocks create anxiety, but little additional damage. A small quake may do enough 'work' to raise a hundred square kilometers one meter. A very large quake may raise many thousands of square kilometers by five or more meters. A hydrogen bomb with a yield of 100 megatons (one megaton is the energy released by one million tons of TNT) releases the energy of a small quake (~5 R). Underground nuclear tests are recorded world-wide on seismographs. A nuclear bomb trace is distinctly different from that of a small natural quake. |