Logarithmic Functions : Earthquakes and the Richter Scale

The intensity level of an earthquake is based on the Richter scale. Using logarithms, the Richter scale measures an earthquake relative to (as a ratio of) the weakest possible tremor.

List the following information in your response:

What is the formula for measuring earthquakes?
Why is a 7.0 earthquake ten times stronger than a 6.0 earthquake?
Pick an earthquake in your region of the world.
Give the measurement of the earthquake.
Explain what this measurement means.
Cite all references used for this problem set.