The dynamic mechanism of plate movement remains a mystery till today. To
explore the mystery we calculated the large-scale deformations caused by
two great circum-Pacific earthquakes, using the dislocation theory in a
spherical Earth model. The result showed that the displacement and
strain caused by the two events gradually expand from the area
surrounding the epicenter to distant places after the earthquake. The
steady-state tensile strain covers most of the Pacific Ocean, reducing
the difficulty of mid-ocean ridge spreading, thereby promoting plate
movement. This study confirms for the first time that there is a two-way
relationship between the circum-Pacific earthquake and tectonic plate,
and the viscous mantle of Earth plays a vital role in the relationship.