Modern geophysics has concluded that the continents are slowly, but smoothly and continuously , carried about the planet atop huge Crustal plates as per Plate Tectonics. The Crust under the continents is quite a bit thicker than under the oceans. This is the same effect as where a fully loaded ship floats lower in the water than when it is empty. The effect this has regarding the Earth's Crust, is that the underside of the earth's Crust has contours which roughly mirror the top surface contours. The theories and details of Plate Tectonics are extensive and involved.
Numerous texts cover the current knowledge of the subject well.
Hawaii represents excellent evidence of this. A single upwelling hot spot in the Mantle keeps breaking through the thin Crust in that area, continuously creating new islands as the Crust moves northwest above it. I suggest that many of the tectonic plates are generally larger in extent than the dimensions of the Mantle convection cells beneath. Therefore, each plate can experience frictional pulls in various directions by the various Mantle convection cells whose tops are moving in different directions in the Mantle beneath. Regarding the Pacific plate, the premise is that there are effectively more cell tops moving Northwest than in other firections.