When a Fault Suddenly Moves It Is Generated?

Sudden motions along faults cause rocks to break and move suddenly, releasing the stored up stress energy to create an earthquake. A slip is the distance rocks move along a fault and can be up or down the fault plane. Slip is relative, because there is usually no way to know whether both sides moved or only one.

When fault move it generates earthquake how this happen?

The friction across the surface of the fault holds the rocks together so they do not slip immediately when pushed sideways. Eventually enough stress builds up and the rocks slip suddenly, releasing energy in waves that travel through the rock to cause the shaking that we feel during an earthquake.

What will happen when a fault at the bottom of the sea suddenly moves?

When the rough spots can no longer hold, the sudden release of the built-up motion releases, and the sudden movement under the sea floor causes a submarine earthquake. This area of slippage both horizontally and vertically is called the epicenter, and has the highest magnitude, and causes the greatest damage.