PPP and tectonic plate motion

March 31st, 2009 by Ricardo PĂ­riz

We have recently introduced our new algorithm for Precise Point Positioning (PPP). One of the things you can do with PPP is to monitor the displacement of your station(s) over long periods of time. Even if your station is installed on a very stable location, it will unavoidably move a little bit over the years due to the slow but steady displacement of the tectonic plate the station is placed on. The plate motion velocity changes a lot from plate to plate, the following map (from UNAVCO) shows a general view of the Earth:

nuvel1a_nnr2

Let us see how we can use PPP in magicGNSS to analyse station motion. According to the Plate Motion Calculator from UNAVCO, the plate motion velocity for Hawaii is around +3 cm per year in the North direction and -6 cm per year in the East direction, with slight variations depending on the actual model (the values are here). This might sound like a very small speed, but it is very observable! The following figure shows the coordinate difference for four stations in Hawaii after one year (from day 08050 to day 09050), calculated with magicGNSS:

comp_coords_0005773

As can be seen on the picture, on average (see mean) the displacement is around +4 cm in the North direction and -6 cm in the East direction, which matches fairly well the values from the tectonic plate models.


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