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7) The Richter Scale Equation is R = log:' where 16 is the intensity of the earthquake (measured by a seismograph reading taken from 100 km from the epicenter of the earthquake) and In is the intensity of a \"standard earthquake\" (whose amplitude is 1 micron = 10\" cm). Basically it's the measure of how much the earth moved during the earthquake (:6) versus how much the earth moves on a normal day (In). On April 18, 1906, there was an earthquake in San Francisco the measured about 7.9 on the Richter scale and killed more than 3000 people. It is believed mat an earthquake 4 times stronger will hit San Francisco within me next 20 years. What will be the magnitude of that earthquake? [6T]