How Do Earthquakes Form?
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, the earthquake occurs.
Here is a photo I got from google about the Earthquake cracking
What is the richter scale
What is epicentre?
What is a tsunami?