How much energy increases per unit on the Richter scale?

• A. 2 times
• B. 31.7 times
• C. 10 times
• D. 100 times

Answer: (B)

The key idea is that the Richter (local magnitude) scale is logarithmic, and the energy released by an earthquake grows much faster than the scale itself. The commonly used relationship is that energy E is proportional to 10 raised to 1.5 times the magnitude: E ∝ 10^(1.5M). So if you increase the magnitude by 1 unit, the energy multiplies by 10^1.5, which is 10^(3/2) ≈ 31.6. In other words, each unit rise in magnitude corresponds to about 31.7 times more energy released. The other options reflect linear or smaller jumps, which don’t align with the logarithmic-energy relationship of earthquakes.