The International Terrestrial Reference
Frame (ITRF), the most accurate global RF available today, is an Earth mass-centered reference frame that
allows a precise determination of any station position as a function of time.
The goal of ITRF is to determine locations and deformations with an improved precision (accuracy 0,1 mm/yr)
everywhere and anytime on Earth. ITRF is constantly being updated since 1988 by
the International Earth Rotation and Reference Systems Service (IERS). Four
spatial geodesy techniques are used: VLBI, SLR, DORIS and GNSS. The
contribution of the latter, including GPS and GLONASS, is the most fundamental.
The latest RF realization , ITRF?2014, is published in 2016 in open access. It
is of great importance for actual geodynamics, being used to determine the co-
and post-seismic deformations (PSD), post-glacial rebounds, a response of earth
crust to loading, and in other applications. But the most important for
geodynamics is the scheme of site velocities. The scheme is in a good
accordance with the ideas of plate
tectonics which were stated earlier and independently: every plate has its own
array of vectors and the plates are divided by boundary zones of three types:
convergent, divergent and transcurrent. The scheme shows that the boundaries may
be stable or moving: convergence and divergence depend on different velocities
of neibouring plates oriented either oppositely or in the same direction (one plate may advance
or lag behind the another). A discrepancy of
within-plate vectors may show also the weaker deformations. The scheme demonstrates a correctness of Euler’ s theorem, stating
that plates move around rotational poles. The comparison of the scheme with
time progressons of oceanic volcanic chains
and stripe magnetic anomalies shows that the vectors of plate movements were
rather conservative during the last 30?40 Ma.
The work has
been supported by the Russian Scientific Foundation, Project # 16?17?10192.