Duringtherupturesofanearthquake,thestrainenergy.△E,.willbetransferredinto,atleast,threeparts,i.e..theseismicradiationenergy(E_s),fractureenergy(E_g),andfrictionalenergy(E_f),thatis,△E=E_s+E_g+E_f.Friction,whichisrepresentedbyavelocity-andstate-dependentfrictionlawbysomeresearchers,controlsthethreeparts.Oneofthemainparametersofthelawisthecharacteristicslipdisplacement.D_c.ItissignificantandnecessarytoevaluatethereliablevalueofD_cfromobservedandinvertedseismicdata.SinceD_ccontrolstheradiationefficiency.η_R=E_s/(E_s+E_g),thevalueofη_risagoodconstraintofestimatingD_c.Integratingobserveddataandinvertedresultsofsourceparametersfromrecordedseismograms.thevaluesofE_sandE_gofanearthquakecanbemeasured,thusleadingtothevalueofη_R.TheconstraintusedtoestimatethereliablevalueofD_cwillbedescribedinthiswork.AnexampleofestimatesofD_c.basedontheobservedandinvertedvaluesofsourceparametersoftheSeptember20,1999M_S7.6Chi-Chi(Ji-Ji).Taiwanregion,earthquakewillbepresented.
