The magnitude of an earthquake, measured on the Richter scale, is log Subscript 10 Baseline StartFraction Upper I Over Upper I 0 EndFraction , where I is the amplitude registered on a seismograph 100 km from the epicenter of the earthquake, and Upper I 0 is the amplitude of an earthquake of a certain (small) size. The largest earthquake struck with a magnitude of 7.5 on the Richter scale. Express this reading in terms of Upper I 0.