EFFECT OF RECENT REVISIONS TO THE GEOMAGNETIC REVERSAL TIME-SCALE ON ESTIMATES OF CURRENT PLATE MOTIONS

Recent revisions to the geomagnetic time scale indicate that global plate motion model NUVEL-1 should be modified for comparison with other rates of motion including those estimated from space geodetic measurements. The optimal recalibration, which is a compromise among slightly different calibrations appropriate for slow, medium, and fast rates of seafloor spreading, is to multiply NUVEL-1 angular velocities by a constant, alpha, of 0.9562. We refer to this simply recalibrated plate motion model as NUVEL-1A, and give correspondingly revised tables of angular velocities and uncertainties. Published work indicates that space geodetic rates are slower on average than those calculated from NUVEL-1 by 6+/-1%. This average discrepancy is reduced to less than 2% when space geodetic rates are instead compared with NUVEL-1A.