At the middle scale is the plate boundary level, where the Plate Boundary Observatory (PBO) will image and characterize the slow deformation of the earth along the western U.S. and Alaska.

• 中级尺度是板块交界，在此，板块交界观测站（PBO）将沿着美国西部与阿拉斯加，拍摄并描绘出地球缓慢变形下的特性。