Why can't earthquakes be predicted in advance?

Mainly because of the complexity of seismic physical process.

Earthquakes are natural phenomena that occur in an extremely complex geological environment. The appearance of earthquake precursors, the geological environment in the focal area and the earthquake process are extremely complicated and changeable. This is a nonlinear process, and the linear process is very easy to handle. Once nonlinearity is involved, the difficulty of processing increases sharply.

Earthquake, also known as ground motion and ground vibration, is a natural phenomenon caused by the rapid release of crustal energy, and seismic waves will be produced in the process. The collision between plates on the earth has caused the dislocation and rupture of plate edges and plates, which is the main cause of earthquakes.