An earthquake in the Japan in 2011 was about 10 9 times as intense as the reference intensity. Find the Richter number for that earthquake. NOTE: Seismologists use the Richter scale to measure and report the magnitude of earthquakes. The equation $R = \log \frac { I } { I _ { 0 } }$ compares the intensity I of an earthquake to a minimum or reference intensity I 0 .
A)10 9
B)10
C)9
D)none of these

Question

An earthquake in the Japan in 2011 was about 10 9 times as intense as the reference intensity. Find the Richter number for that earthquake. NOTE: Seismologists use the Richter scale to measure and report the magnitude of earthquakes. The equation $R = \log \frac { I } { I _ { 0 } }$ compares the intensity I of an earthquake to a minimum or reference intensity I 0 .
A)10 9 
B)10
C)9
D)none of these

Quizplus · Accepted Answer

The Richter number is calculated using the formula $R = \log \frac { I } { I _ { 0 } }$. Given that the intensity $I$ is $10^{9}$ times the reference intensity $I_0$, the Richter number $R$ is $\log(10^9) = 9$.

An Earthquake in the Japan in 2011 Was About 10 R=log⁡II0R = \log \frac { I } { I _ { 0 } }R=logI0​I​

An Earthquake in the Japan in 2011 Was About 10 $R = \log \frac { I } { I _ { 0 } }$