Why can such a developed country detect earthquakes every time?

Earthquakes are unpredictable Earthquakes will bring about various physical and chemical changes underground and above ground, and provide people with information. As long as people carefully observe and master the law of earthquake precursors, earthquake prediction will come true one day. In earthquake prediction, seismologists in China have made gratifying achievements. 1On February 4th, 975, China Haicheng earthquake with magnitude 7.3 was successfully predicted, which was the first successful earthquake prediction in human history. Subsequently, the1May 29th, 976 Longling earthquake in Yunnan and the1August 6th and August 29th, 976 Songpan-Pingwu earthquakes in Sichuan were successfully predicted. In the last ten years, there have been several good earthquake predictions. Successful earthquake prediction not only greatly reduces casualties, but also has obvious economic and social benefits. These earthquake examples show that earthquakes are precursors and can be predicted and prevented. In the period before the earthquake, there will always be some abnormal changes near the earthquake zone. Such as the change, sudden rise, sudden drop or bad taste, turbidity, ringing and bubbling of groundwater. Meteorological changes, such as sudden cold weather, sudden heat, drought and flood, electromagnetic field changes, abnormal reactions of animals and plants before earthquakes, etc. Through the comprehensive study of these reactions, coupled with the processing and analysis of observation data by professional departments from the aspects of earthquake mechanism, seismogeology, geophysics, geochemistry, biological changes, celestial influence and meteorological anomalies, the time, place and magnitude of earthquakes can be predicted. For example, 1975' s successful prediction of Haicheng M = 7.3 earthquake is an example. However, due to the complexity of the causes of earthquakes and the suddenness of earthquakes, as well as the limited scientific level of people at present, earthquake prediction is still a worldwide problem, and there are no reliable methods and means to accurately predict all destructive earthquakes in the world. Therefore, seismologists and experts all over the world are trying to explore. However, earthquake prediction is one of the difficult problems in contemporary science, and it is still in the semi-empirical and semi-theoretical stage. Several earthquakes of magnitude 7 or above that occur on land every year in the world and some moderate earthquakes that occur in China in recent years, especially the Tangshan earthquake of magnitude 7.8 of 1976, failed to make short-term and imminent predictions. These earthquakes have brought great disasters to mankind. Therefore, earthquake prediction needs the cooperation of scientists all over the world, the attention of the whole society, and the efforts of generations of seismologists before it can be finally overcome in theory.