Question

what is earthquake in simple words

Answer 1

earthquake is a series of vibrations on the earth's surface caused by seismic waves due to sudden faults in the plate boundaries as a result of built up energy 
the seismic focus is the point at which the earthquake originates ......

Answer 2

An earthquake is a violent movement of the rocks in the Earth's crust.Earthquakes are usually brief but they may repeat over a long time.They are caused due to sudden release in the Earth's Crust. Earthquakes may take down buildings and cause death and injuries.The study of Earthquake is Seismology.Earthquakes are measured using observations from seismometers.The intensity of shaking is usually measured by Richter Scale.