The Devastating Haiti Earthquake: Questions and Answers

What does a magnitude 7.0 mean?

Magnitude measures the energy released at the source of the earthquake. Since magnitudes are given on a logarithmic scale, a 7.0-magnitude earthquake would correspond to 10 times greater ground motion than a 6.0-magnitude temblor. The total amount of energy released by the earthquake, however, goes up by a factor of 32 for every unit increase in magnitude.

Geoscientists also look at an earthquake’s intensity, which measures the strength of shaking produced by the earthquake at a certain location and is determined from the effects that shaking has on people, structures and the environment.