I. Geological methods
It is a method to estimate the location and intensity of earthquakes macroscopically according to the geological and structural conditions of earthquakes. This method can be used to divide the dangerous areas of future earthquakes in a large area and determine the dangerous areas with different intensities. This kind of work is called earthquake zoning. Because the geological time scale is too large, the time prediction of earthquakes cannot rely on this method.
Second, statistical methods.
It is to explore the possible statistical laws from the records of earthquakes, estimate the danger of earthquakes and find out the probability of earthquakes with a certain intensity. The reliability of statistical methods depends on the amount of data. China has a long history. In some areas, there are abundant seismic data, and using statistical methods can provide meaningful results.
Third, precursor method.
It is a method to predict the time, place and intensity of future earthquakes according to precursor phenomena. The focus of geological method is the geological conditions of earthquake occurrence and the change of seismic activity on a relatively large spatial and temporal scale. Statistical methods only point out the probability of earthquake occurrence and some "average" state of seismic activity. If we want to clearly predict the location, intensity and time of earthquakes, we still have to rely on the precursors of earthquakes. Therefore, finding earthquake precursors is the core problem of earthquake prediction. In order to obtain reliable earthquake precursors, long-term and extensive observation and research are necessary.