The Richter Scale

Table of Contents

Richter Scale

The magnitude of earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs A seismograph produces a seismograph which gets recorded on a ticker tape. it looks like this: Scientists use these squiggles to get a single magnitude for the earthquake

Magnitude Chart

Each level is 10x more powerful than the previous level Magnitude of 3→ Magnitude of 4 is 10x more powerful. Magnitude 3 → 5 is 100x more powerful

Richter Formula

M = $\log (\frac{I}{I_o})$ $M_1-M_2\log (\frac{I_1}{I_2})$ $\frac{I_1}{I_2}=10^{M_1-M_2}$

Example Question

A earthquake of 7.5 magnitude is 375 times as intense as a minor earthquake. find the magnitude of minor earthquake. $\frac{I_1}{I_2}=10^{M_1-M_2}$ $\frac{375I_2}{I_2}=10^{7.5-M_2}$ $375=10^{7.5-M_2}$ $M_2=7.5-\log 375$ = 4.92