A way of estimating the characteristic slip displacement

During the ruptures of an earthquake, the strain energy, ΔE, will be transferred into, at least, three parts, i.e., the seismic radiation energy (E_s), fracture energy (E_g), and frictional energy (E_f), that is, ΔE=E_s+E_g +E_f. Friction, which is represented by a velocity- and state-dependent friction law by some researchers, controls the three parts. One of the main parameters of the law is the characteristic slip displacement, D_c. It is significant and necessary to evaluate the reliable value of D_c from observed and inverted seismic data. Since D_c controls the radiation efficiency, η_R=E_s/(E_s+E_g), the value of η_R is a good constraint of estimating D_c. Integrating observed data and inverted results of source parameters from recorded seismograms, the values of E_s and E_g of an earthquake can be measured, thus leading to the value of η_R. The constraint used to estimate the reliable value of D_c will be described in this work. An example of estimates of D_c based on the observed and inverted values of source parameters of the September 20, 1999 M_S 7.6 Chi-Chi (Ji-Ji), Taiwan region, earthquake will be presented.