How to Compare the Strength of Earthquakes

The earthquake that shook Nepal on Tuesday was magnitude 7.3. The powerful quake that hit on April 25, killing more than 8,000 people, was magnitude 7.8.

That might not seem like a big difference, but it is. Every 0.1 change in magnitude represents a big jump in the power and amount of energy released by a quake.

April’s deadly quake was roughly three times as big as the 7.3 temblor on Tuesday and released roughly five-and-a-half times more energy, giving it more destructive force. The exact calculations and logarithmic equations to work this out are here.

The epicenter of Tuesday’s earthquake was 15 kilometers below the Earth’s surface, making it five kilometers deeper than the April 25 temblor.