### Home > CCA2 > Chapter 9 > Lesson 9.1.1 > Problem 9-13

The **Richter scale** assigns a magnitude number to quantify the energy released by an earthquake. The magnitude of an earthquake was defined by Charles Richter to be log

*is the intensity of the earthquake (measured by the amplitude of a seismograph reading taken*

*is the intensity of a “standard earthquake” (whose amplitude is*

How many times stronger is an earthquake that measures

on the Richter scale than an earthquake that measures ? times How many times stronger is an earthquake that measures

than an earthquake that measures ? Give your answer both as a power of and as a decimal. Make sure your answer has the same level of precision as the Richter measurements.

What is the magnitude of an earthquake that is half as strong as an earthquake measuring

on the Richter scale? Calculate the energy released by a Richter measurement of

. Then divide in half. You may want to use logs or guess and check to find the answer.