The magnitude of an earthquake, measured on the Richter scale, is given by R(I)=log (I/I0),
Where I is the amplitude registered on a seismograph located 100 km from the epicenter of the earthquake, and I0 is the amplitude of a certain small size earthquake. Note: the “common logarithm y x = log( ) is understood to be base 10.
A) On June 15, 1999, the city of Puebla in central Mexico was shaken by an earthquake that measured 6.7 on the Richter scale. Express this reading in terms of I0.
B) On September 19, 1985 Mexico’s largest recent earthquake measuring 8.1 on the Richter scale, killed about 10,000 people. Express the magnitude of an 8.1 reading in terms of I0.