Question

What is the main difference between intensity and magnitude?

Answer 1

Magnitude is a measure of the energy released by the earthquake - it is an absolute value and does not vary with where it is measured. Intensity measures the strength of the shaking at a particular location and will vary with distance, substrate conditions and other factors. It is a subjective measure which depends on observation, not measurement. The reference below sets it all out for you. Hope this helped:)