THEORETICAL BASIS ON RELATIONSHIPS BETWEEN FOCAL PARAMETERS AND EARTHQUAKE MAGNITUDE

摘要: Not only for a real earthquake but also hypothetical earthquake, it is very convenient if we can estimate the first approximations of focal parameters, such as fault area, dislocation, seismic moment, rise time, etc., by using empirical relations. It desirable that these relations have simple forms possible, explain previous observations even rather roughly, be predicted From theory on model available, and are consistent with each other.In this paper, relationships between some parameters magnitude proposed several investigators theoretically reexamined based upon dislocation theory. The following new Shallow large earthquakes (M_??_5), which favor theoretical considerations, axe suggested; logS(km2)=M-4.07, logD0(cm)=0.502M-1.40, logM0(dyne·cm)=1.50logS(km2)+22.3, where M magnitude, S D0 mean M0 moment. These provide constant strain drop plane, dynamic similarity, proportionality time to S, energy (constant apparent stress) relation log T0-0.5M, T0 being predominant period particle velocity. Of course must modified when many refined data accumulated in future studies process well developed.