Question

what is earthquake how he formed

Answer 1

Earthquake is a shaking of the earth and it happens by the movement in tenconic plates

Answer 2

An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities.
-------------how are they formed-------------
Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. ... When the rocks break, theearthquake occurs.