Abstract: Basing on their Euler Poles, we calculated the relative velocities between every two plates in the typical global plate motion models, respectively, and estimated area changes along these boundaries. In our calculation, plates on both sides accommodate the area changes depending on the boundary types: extensional, convergent or transform, so we can estimate area changing of every plate and then the global surface area change. Our preliminary results show that the area of southern hemisphere increased while that of the northern hemisphere decreased in the past 1 million years, and the global area increased between 26000 and 36000 km², which was corresponding to 160~250 m incremental in the earth's radius if all these areas were attributed to the earth's expanding. Taking NUVEL-1 model as an example, among all the 14 plates in this model, 11 of them were in decreasing, but the global area increased because of the larger amount of incremental from Africa, North America and Antarctica. Finally, we also discussed factors affecting the global area change such as subduction zone retreating and backarc spreading.

Key words: Plate Motion, Nuvel-1 Model, Pacific Plate, Subduction Zone