The intensity of an earthquake is measured relative to the intensity of a standard zero-level earthquake of intensity I₀. The relationship is equivalent to I = I₀ × 10^R, where R is the Richter scale measure. For example, if an earthquake has magnitude 5.0 on the Richter scale, then its intensity is calculated as

which is 100,000 times as intense as a zero-level earthquake.

To compare an earthquake that measures 8.1 on the Richter scale to one that measures 5.2, find the ratio of the intensities.

Therefore, an earthquake that measures 8.1 on the Richter scale is almost 800 times as intense as one that measures 5.2.

Suppose an earthquake measures a value of x on the Richter scale. How does the intensity of a second earthquake compare if its Richter scale measure is x + 3.0? If its Richter scale measure is x - 1.0?

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1 = 10 x 105.0 = 10 x 100,000,