The Richter Scale Measures the Magnitude of an Earthquake Using $M=\log \frac{I}{S},$

Short Answer

The Richter Scale measures the magnitude of an earthquake using the formula $M=\log \frac{I}{S},$ where I is the intensity in $\mathrm{mm}$ and $\mathrm{S}$ is a constant of $0.001 \mathrm{~mm}$ . At what rate is the magnitude changing at when the intensity is $4000 \mathrm{~mm}$ and increasing at $1000 \mathrm{~mm} / \mathrm{min}$ .