Microplate motions in the hotspot reference frame

In this paper, we compute absolute motions that describe the motion of plates and microplates with respect to the mesosphere. In plate kinematic and dynamic analyses, two different absolute reference frames have been utilized: fixed-hotspots and meanlithosphere. The first, the hotspot reference frame , is based on the assumption that individual hotspots are fixed relative to the mesosphere and to each other (Morgan, 1972; Wilson, 1973). Under this hypothesis, a seamount chain such as the Hawaiian-Emperor describes the motion of the overlying Pacific plate relative to the Hawaiian hotspot assumed stationary. The second frame, for the no-net-rotation condition (NNR) (Solomon and Sleep, 1974), rests upon the assumption that lithosphere and asthenosphere are uniformly coupled. Because both absolute reference frames are referred to the mesosphere, any difference between the frames would be interpreted as a net-rotation of the lithosphere with respect to the mesosphere (Forsyth and Uyeda, 1975). Here, we choose the hotspot reference frame (Gripp and Gordon, 2002) to describe 52 plate and microplate motions. In addition, we compute plate and microplate velocities in the corresponding NNR frame.