Global plate motion models incorporating the velocity field of ITRF96

摘要

In this paper, incorporating the ITRF96 velocity field that is free of any tectonic plate model assumption, a new present-day plate motion model relative to the ITRF96 reference frame, called the ITRF96VEL, is determined. The total angular momentum of all tectonic plates with regards to the ITRF96VEL shows that the ITRF96 rotates in a right-handed sense relative to the no-net-rotation (NNR) reference frame at O.164°/m.yr. about 50.7°S, 65.8°E. This means that ITRF96 is not sufficiently concordant with the definition of the Conventional Terrestrial Reference System (CTRS). In order to more properly compare plate motions from the ITRF96 velocity field with the NNR-NUVEL1A, another plate motion model relative to the NNR reference frame, called the NNR-ITRF96VEL, is also established. The results indicate that the NNR-ITRF96VEL is quite consistent with the NNR-NUVEL1A. The consistency testifies to the reliability of the NNR-NUVEL1A, and shows the tectonic plate motions were steady over past millions of years.