Earthquakes are measured using seismographs, which monitor the seismic waves that travel through the Earth after an earthquake strikes.
Scientists used the Richter Scale for many years but now largely follow the “moment magnitude scale,” which the U.S. Geological Survey says is a more accurate measure of size.
Here are the magnitude classes:
Microearthquake:
— Magnitude: Less than 3.0
— Damage: Little to none
Minor earthquake:
— Magnitude: 3.0 – 3.9
— Damage: Little to none
Light earthquake:
— Magnitude: 4.0 – 4.9
— Damage: Moderate
Moderate earthquake:
— Magnitude: 5.0 – 5.9
— Damage: Considerable
Strong earthquake:
— Magnitude: 6.0 – 6.9
— Damage: Severe
Major earthquake:
— Magnitude: 7.0 – 7.9
— Damage: Widespread, heavy
Great earthquake:
— Magnitude: 8.0 and up
— Damage: Tremendous