Guide
Magnitude vs intensity: why one earthquake feels different everywhere
Magnitude is a single number for how much energy an earthquake released at its source. Intensity describes how strong the shaking and damage were at a specific place, and it varies with distance, depth and local soil. One earthquake has one magnitude but many intensities.
What magnitude tells you
Today most agencies report moment magnitude (Mw), which is based on how much of a fault slipped and how far. The scale is logarithmic. Each whole-number step is about 10 times larger in measured ground motion and about 32 times more energy. A magnitude 7 releases roughly 1,000 times the energy of a magnitude 5.
What intensity tells you
The Modified Mercalli Intensity scale runs from I (not felt) to XII (near-total destruction) and describes what people observed. USGS builds shaking maps from instruments and from “Did You Feel It?” reports submitted by the public. A deep magnitude 6 far from a city can be a II or III. A shallow magnitude 4.5 under a town can reach VI.
Why the same earthquake feels different
- Distance. Shaking weakens as waves travel.
- Depth. A shallow earthquake puts the energy closer to the surface.
- Soil. Soft sediment and filled land amplify shaking compared with solid rock.
- Buildings. Unreinforced masonry and older construction suffer more than modern, code-built structures.
What each magnitude range usually means
| Magnitude | Typical effect | Worldwide per year* |
|---|---|---|
| Under 3.0 | Usually not felt; recorded by instruments | Over a million |
| 3.0 – 3.9 | Often felt nearby; rarely causes damage | ~130,000 |
| 4.0 – 4.9 | Noticeable shaking, rattling objects; damage unlikely | ~13,000 |
| 5.0 – 5.9 | Can damage weak buildings close to the epicentre | ~1,300 |
| 6.0 – 6.9 | Can be destructive within about 100 km | ~130 |
| 7.0 – 7.9 | Major; serious damage over larger areas | ~15 |
| 8.0 and above | Great; can cause destruction hundreds of km away | ~1 |
*Approximate long-term averages published by USGS. Counts for the smallest sizes are estimates.
You can see both numbers for any earthquake on our live list: magnitude, depth and distance from you.