Using Charles Richter's formula Magnitude of Earthquake M = log I / S (where I is the intensity of the earthquake taken 100km from epicenter, S is the intensi

Using Charles Richter's formula Magnitude of Earthquake M = log I / S (where I is the intensity of the earthquake taken 100km from epicenter, S is the intensity of a standard earthquake) First earthquake 7.8 = log I1 / S Second earthquake 7.1 = log I2 / S If we solve this for I1/I2, we get 10 ^ 1.10 ~ 12.5 > The intensity of first earthquake was 12.5 times as intense as the later earthquake.