Describe the velocities of points at the Earth's surface due to plate tectonic motions and either derived geophysically from sea floor spreading rates, transform fault and earthquake slip azimuths (see for example NUVEL-1, NNR-NUVEL-1, NUVEL-1A, NNR-NUVEL-1A) , or from geodetic space techniques like VLBI, SLR and GPS (Actual Plate Kinematic Model - APKIM). Plate motions are described by geocentric rotation vectors either given by the geographic coordinates PHI,LAM [°] of the rotation pole and the angular velocity OMEGA[ °/Ma]. The velocities of a point (10x10° grid) with geographic coordinates phi,lam [°] are computed by:

dphi/dt = OMEGA·cos(PHI)·sin(lam-LAM)

dlam/dt = OMEGA·[sin(PHI) - cos(lam-LAM)·tan(phi)·cos(PHI)] (dphi/dt & dlam/dt given in [°/Ma])

Select 'Plate Kinematic Model, 'All Plates' or a specific plate followed by <Calculate a plate grid>. Velocities at a given point is listed in cm/yr. A mean velocity is listed for each plate after individual point estimates. When you 'Exit' vector will be drawn on the screen.