On January 2, 2011, a 7.1 magnitude earthquake struck the central coastal area of Chile, approximately 45 miles northwest of Temuco. No major damage or injury was reported when the earthquake hit, though the quake was felt 370 miles away in Santiago. Find the intensity of the earthquake and express its intensity in terms of the intensity of a standard earthquake, that is, I0. I0 Solution The magnitude, M, of an earthquake on the Richter scale is equal to the log of the intensity of the earthquake, I, divided by the intensity of a standard earthquake, I0. If you plug in 7.1 for M, you get: 7.1 = log (I/ I0) If you change the equation from log form to exponential form, you get 107.1 = I / I0 Then multiply both sides of the equation by I0 to get the intensity. 107.1 * I0 = I You could leave your answer as 107.1 or evaluate it to find that the earthquake is 12,589, 254.12 times more intense than a standard earthquake. Hope this helps!.