In 1960s, J.S. Lee (Si-Guang Li) pointed out that, tectonic stress and its variation have tight relationship with earthquake, and unraveling the stress variation process by in-situ stress measurement is key to realize earthquake prediction. On the basis of Dr. Lee's speeches andmy own experiences of the related practices, some significant ideas from Dr. Lee on the earthquake prediction were introduced. Today, his ideas on "safe island" and earthquake prediction still have theoretical and practical significances. According to Prof. J.S. Lee's previous speeches and instructions, combined with our own working experiences, his main ideas and opinions about earthquake prediction are introduced below, which still have theoretical and practical significances in the present.
After the 1962 Xinfengjiang earthquake in Guangdong, Prof. J.S. Lee proposed several new ideas about works on earthquake and began to organize research teams and gradually push forward the earthquake prediction research. J.S. Lee pointed out: "Most of the earthquakes occur on the Earth's surface" (Li, 1973). "According to this fact, we should make notices on the tectonic issues at the Earth's surface, and earthquakes occur in the zones (or areas, sites) with special tectonic forms. Therefore, we should at first deep investigate the zones (points) on the earth's surface, where the tectonic phenomena happened" (Li, 1973). He also clearly pointed out: "Earthquakes are closely related to tectonic stress and its variations" (Li, 1974). "Tectonic stress should exist, and an earthquake can be generated when tectonic stress changes to a certain degree. It is hard to imagine that this force is generated within a few hundredth of a second, and then it should have a gradually strengthening process, which is a stress accumulation process" (Li, 1974).
