The Magnitude M of an Earthquake Is Measured Using the Richter

Short Answer

The magnitude M of an earthquake is measured using the Richter Scale
where M is the magnitude
E is the seismic energy energy released by the earthquake ( in joules)
E₀ is the energy released by a reference earthquake E₀ = 10^4.4 joules
On September 25, 2003, an earthquake that measured
7.0 on the Richter scale shook Hokkaido, Japan. How much energy (joules) did the earthquake emit?