Variation of Focal Parameters and Medium Characteristics During Small Earthquakes

In earthquake prediction, strong earthquakes are usually preceded by a series of small earthquakes. Thus, correct identification of those small earthquakes characteristics tell precursor observations and will lead to accurate prediction and judgement of impending main shocks. This paper discusses seismic source dynamic parameters, medium and rupture characteristics, and their variations during small earthquakes. Focal mechanism and its variation before and after main shock are also demonstrated along with several seismic examples to summarize the change of rupture characteristics (primary rupture direction, ambient shear stress, and waveform’s temporal) and periodicity during small and medium earthquakes.