On “whether earthquake precursors help for prediction do exist”

Whether earthquake precursors help for prediction do exist? This paper attempts to answer this question from the mechanism of tectonic deformation. Because an earthquake is sudden slip on a fault, a physical process from slow to fast should happen prior to its occurrence. Consequently, observable precursors should appear before earthquakes. Whereas, to detect such precursors remains a difficult task. In addition to some limitations of the effort, such as observational instruments, deployment of measurement sites, and complicated relations between the precursor and main shock, it is an important step whether the crucial temporal stage can be recognized. An earthquake is a mechanical process. From the differential stress-time process, the deformation of the seismogenic fault should have four states, i.e. stability, meta-stability, meta-instability, and instability. In the stability and meta-stability stages, when the external force is removed, the strain of the fault can be recovered to some extent. As the causative fault enters the meta-instability stage, it is just the deformation stage dominated by release behind the stress peak strength. After this moment, even if no external force is loaded, the fault has entered an evolutional stage of self-instability, i.e. an irreversible deformation stage, indicating the seismic event is bound to occur. Thus, this stage has a relation of uniqueness with the burst of the earthquake.