How earthquakesare measured
Earthquakes are most commonly measured by magnitude, a scale based on the amount of seismic energy released by the quake. On the magnitude scale, each increase of one whole number translates to 32 times more energy.
Class
Magnitude
Impact
3.0-3.9
Minor
May be felt
4.0-4.9
Light
Likely felt
Minor damage
may occur
5.0-5.9
Moderate
Damage
may occur
6.0-6.9
Strong
Damage
expected
7.0-7.9
Major
Significant
damage expected
8.0 and up
Great
Class
Magnitude
Impact
3.0-3.9
Minor
May be felt
4.0-4.9
Light
Likely felt
Minor damage
may occur
5.0-5.9
Moderate
Damage
may occur
6.0-6.9
Strong
Damage
expected
7.0-7.9
Major
Significant
damage expected
8.0 and up
Great
Minor
Light
Moderate
Strong
Major
Great
Class
3.0-3.9
4.0-4.9
5.0-5.9
6.0-6.9
7.0-7.9
8.0 and up
Magnitude
Impact
Damage
may occur
Damage
expected
May be felt
Likely felt
Minor damage
may occur
Significant
damage
expected
