The earthquakes are caused by:

Rocks which are firmly attached to each other inside of the crust of the earth surface suddenly moving adjacent to the fault line.

Earthquake Magnitude:

Intensity of an Earthquake

The intensity of an earthquake is how much the ground shakes at a certain point due to an earthquake. The intensity is classified into 10 stages in Japan.

0People do not feel the ground motion.
1People inside of buildings feel the ground motion slightly.
2Many people inside of buildings feel the ground motion.
3Most people inside of buildings feel the ground motion
4Suspended objects shake violently.
5(lower)Dishes fall from shelves.
5(upper)Heavy furniture and gravestones move and the water pipes can be damaged.
6(lower)The windows of buildings fall out and cracks in the ground and landslides occur.
6(upper)People cannot stand.
7People cannot stand and buildings with weak earthquake resistance are demolished or collapse.


The magnitude is the value calculated by estimating the total amount of energy released during the earthquake.

Moment magnitude

The moment magnitude is the value where the long-period ground motion is considered for the magnitude calculation method.