What is Earthquake Prediction?
Earthquake Prediction is one of the branches of the science of Seismology which deals with the prediction of the future earthquake along with its specific time, space and magnitude.

 What are the various methods of earthquake prediction?
Generally there are two approaches:
Precursors: It is an anomalous phenomenon that gives effective warning of an upcoming earthquake.

Animal behaviour
Certain abnormal behaviours of animals have been recorded some tens of seconds {sometimes even days} of an earthquake. However these signals are explained to be responded to the P- wave that comes about twice time earlier than the S- wave which causes major shaking of the ground.

Weather Change
Abnormal weather condition has been experienced before a tremor in some cases. Nepal had experienced notable change in the atmospheric condition before 7.8 hit in 2015 A.D. Huge fall in the temperature had been detected which continued for several days recording a fierce storm in the capital city. However USGS denies the myth weather can trigger earthquake. But they believe that earthquake can affect weather.

Changes in Vp/Vs
Vp and Vs are the symbols for the velocity of the seismic P {primary wave} and the velocity of the seismic S {secondary wave} respectively. The experiments based on this method predict that the ratio of these two velocities changes when the rock is near the rupturing point. Though it led some successful predictions in 1973, later it was suggested to be fluke. Because its predictions failed to occur in 1976. Wikipedia has stated.

 Emission of radioactive gases
Most rock contains gases. One of such gases is Radon. It is believed to be released before a tremor caused by high stress on the rock. But it is said not be correlated as it is linked to an earthquake with thousand kilometres distance, months of time gap and inaccurate magnitude.

 Trends: This approach is based on statistics. This method tends to be useful for long term prediction, and so merge into earthquake forecasting.

Seismic gap
According to this module at the contact where two plates slip past each other every section must slip in course of time. They do not slip at the same time. It happens in different stages. In this model, a big earthquake is expected in the segment where earthquake has not occurred for a long time. But the experiments say that its time and magnitude are not known.
Discovered by Don Prince