about地震,please help me!!!!!

Firstly, Japan is located along a DESTRUCTIVE PLATE BOUNDARY.
So, there is a collision between the OCEANIC AND CONTINENTAL PLATES.
There is also a SUBDUCTION ZONE.
Therefore, LOTS OF STRESS ACCUMULATES between the rock masses of different plates.
When the rock massess are caracked, MUCH ENERGY is RELEASED and PRODUCE VIBRATIONS.

That's why Japan always has earthquake.

It is because Japan is in a area of an earthquake area