The primary cause of an earthquake

The primary cause of an earthquake is faults on the crust of the earth. Earthquakes are caused by sudden movements of rock beneath the earth. Stresses in the earth cause blocks of rock to break, then move along a fault, or crack. Rocks and earth may slip in any direction along a fault sideways or up and down. The energy accumulated during faulting is released. If the edge of the crust is moving or close to any country, that country will be a high risk of disasters, such as Japan, Philippines, Indonesia and New Zealand, etc.