Magnitude and Earthquake

Magnitude is the scale of an earthquake. Seismic intensity indicates the intensity of tremors at various places, and differs depending on the distance from the epicenter or other conditions. In general, even if the magnitude is large, seismic intensity may be small for a place far from the epicenter.

Earthquake tremors and envisioned damages (from Japan Meteorological Agency seismic intensity scale chart)

Intensity 0
Imperceptible to people

Intensity 1
Felt by only some people in a building

Intensity 2
Felt by most people in a building. Hanging objects such as lamps swing slightly.

Intensity 3
Felt by most people in a building. Dishes in the cupboard sometimes rattle.

Intensity 4
Most sleeping people awake. Unstable ornaments sometimes fall. People walking on the street notice the tremor.

Intensity 5 (lower)
Most dishes in the cupboard and most books on a bookshelf will fall. Windowpanes are sometimes broken.

Intensity 5 (upper)
Heavy furniture such as a chest of drawers may fall. Vending machines on the streets sometimes fall. Many automobiles stop, because it becomes difficult to drive.

Intensity 6 (lower)
Difficult to keep standing. In some buildings, wall tiles and windowpanes are damaged and fall. It is impossible to open the door in many cases.

Intensity 6 (upper)
Impossible to keep standing and to move without crawling. Most heavy and unfixed furniture moves or falls. Sliding doors are dislodged from their tracks.

Intensity 7
Impossible to move freely. The ground is considerably distorted by large cracks and fissures, and slope failures and landslides take place.