Abstract This paper presents several applications of spherical dislocation theory to the 2011 TohokuOki earthquake. 1) We first calculate the coseismic horizontal displacements of the great earthquake using spherical dislocation theory. Our results show that as follows.a) The coseismic displacements are relatively bigger at areas perpendicular to the fault plane; b)most of the horizontal displacements point to the epicenter; c)as far as 5 000 kilometers from the epicenter the coseismic horizontal displacements reach up to 3 mm; d)in total, our theoretical predictions agree very well with the observations detected by GPS in far field. 2) Comparing with the theoretical displacements themselves, the discrepancies between two sets farfield displacements, which are deduced from two independent fault models, are about 1%-4% west to the epicenter but about 6%-15% east to the epicenter. The misfits near the epicenter are much bigger than those of farfield. Such discrepancies indicate the limited constraint capability of the dense GPS data on Japan Islands to the fault model of the 2011 TohokuOki earthquake, because of GPS stations’ ill distribution relative to the epicenter. 3)We constraint the total seismic moment of the 2011 TohokuOki earthquake within (3.24-4.96)×10 22 Nm using the farfield GPS data.The corresponding moment magnitude is about Mw8.97-9.10. 4) At last, the coseismic strains caused by the 2011 TohokuOki earthquake are roughly crosscurrent with the background of stress change fields at North China. As indicate that the crustal blocks at North China are relaxed as a whole due to the great earthquake.
