Earthquake Calculator

What is an Earthquake?

An earthquake is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the air and wreak destruction across entire cities.

The Richter Scale

The Richter magnitude scale (also Richter scale) assigns a magnitude number to quantify the energy released by an earthquake. Developed by Charles F. Richter in 1935, it's a logarithmic scale, meaning each whole number increase represents a tenfold increase in measured amplitude and approximately 31.6 times more energy release.

Features

• Calculate earthquake magnitude from energy release
• Determine energy from magnitude (Richter scale)
• Calculate magnitude from seismograph amplitude and distance
• Compare two earthquakes to see energy and amplitude differences
• View detailed classification and effects
• Step-by-step calculation breakdown
• TNT equivalent energy comparison
• Frequency information for each magnitude range

Calculation Methods

This calculator uses the Gutenberg-Richter relationship for energy calculations: log₁₀(E) = 1.5M + 4.8, where E is energy in Joules and M is magnitude. For amplitude-based calculations, it uses the original Richter formula: M = log₁₀(A) + 3log₁₀(8Δ) - 2.92, where A is amplitude in millimeters and Δ is distance in kilometers.

Magnitude Classifications

• Micro (< 2.0): Not felt, recorded on seismometers only
• Minor (2.0-3.0): Often felt, but rarely causes damage
• Light (3.0-4.0): Noticeable shaking of indoor objects
• Moderate (4.0-5.0): Can cause damage to poorly constructed buildings
• Strong (5.0-6.0): Damage to well-designed buildings, major damage to poorly built structures
• Major (6.0-7.0): Serious damage over larger areas
• Great (7.0-8.0): Serious damage over areas of several hundred kilometers
• Epic (> 8.0): Devastating in areas several thousand kilometers across

Understanding Energy Release

The energy released by an earthquake increases exponentially with magnitude. A magnitude 5.0 earthquake releases about 32 times more energy than a magnitude 4.0 earthquake, and about 1,000 times more than a magnitude 3.0 earthquake. This exponential relationship explains why even small increases in magnitude represent dramatically more powerful earthquakes.

Historical Context

Some of the most powerful earthquakes ever recorded include the 1960 Valdivia earthquake in Chile (magnitude 9.5), the 1964 Alaska earthquake (magnitude 9.2), and the 2011 Tōhoku earthquake in Japan (magnitude 9.1). These massive earthquakes released enormous amounts of energy and caused significant damage and loss of life.

Important Notes

• The Richter scale is logarithmic, not linear
• Modern seismology often uses the moment magnitude scale (Mw) for large earthquakes
• Local magnitude can vary from moment magnitude
• Earthquake effects depend on many factors beyond magnitude, including depth, distance, and local geology
• This calculator provides estimates based on standard formulas
• Actual seismic measurements may vary based on instrumentation and methodology