F.F.L.and.F.F.D.^* are two important quantities of the earthquake source parameters.It is important for earthquake prediction to find indicated scales of them before earthquake occurs.The special value between F.F.L.and F.F.D.represents the harmonic property in dis ocation procedure of fault at depth.This property is helpful for us to understand source circumstance.
In this paper,we have collected the fault data of great earthquakes occurred in regions of China,Japan and the United States,then analysed and processed these data,and obtained approximate linear relationship between F.F.L.and F.F.D.,the former of which is 10^-5 order of magnitude larger than the latter.
In addition to the above-mentioned,depending on the harmonic relationship between F.F.L.and F.F.D.in the earthquake procedure,we discuss the problem whether the earthquake fault before the 1976 Tangshan earthquake creeped or not,and whether the slippage in the Tanlu fault can do or not for handred kilometers of horizontal offset.