QuakeMap Live
The Richter scale and earthquake magnitude
Magnitude describes an earthquake’s size. Intensity describes the shaking experienced at a particular location. A single event can therefore have many intensity values, and the magnitude alone cannot tell you what happened to a building.
What was the Richter scale?
The original Richter scale is a local magnitude scale (ML) developed for southern California. It estimates size from the amplitude of recorded waves, with an adjustment for distance. For large earthquakes, scientists commonly use moment magnitude (Mw), which relates to the size of the rupture and how far the fault slipped. Check the label next to a reported number to see which scale the source used.
Read the scale beside the number
Mw, ML and mb use different measurements and assumptions. QuakeMap Live retains the source’s scale and original measurements rather than silently converting every value to a ‘Richter’ number. Revised estimates can change as observations improve. Compare values on the same scale where possible.
Energy is not local damage
For comparable moment magnitudes, a difference of one unit corresponds approximately to 32 times the released energy. This is an approximate relationship, not a damage forecast. Distance, depth, ground conditions and buildings influence shaking. MMI and Japanese Shindo describe intensity using different systems; this site does not invent conversions between them.
Data sources
Sources reviewed:
QuakeMap Live editorial · AI-assisted text and translation