Earthquakes and aftershocks are tremors that occur due to the discharge of energy from the crust of the earth. The main thing that distinguishes an earthquake from an aftershock is the magnitude of the quake arising from the same epicenter. Natural or human reasons can trigger earthquakes, any seismic activity is deemed an earthquake when it creates seismic waves, and earthquakes are set off by natural or human reasons.
Many events may incite an earthquake, such as landslides, volcanic activity, and causes such as mine blasts or nuclear tests. The main shock and the aftershock occur in the same region with different magnitudes. The first seismic wave produced from the epicenter is of the highest magnitude is considered the mainshock, while the shocks that occur after the mainshock that are of lower magnitude are called aftershocks.
Aftershocks take place as the crust of the earth adapts itself to the displaced plane. They occur away from the fault plane in a distance which is equal to the length of the break.