SNARF Working Group - Report of the Second SNARF Workshop

Eos Trans. AGU, 85(17), Jt. Assem. Suppl., Abstract G21D-05, 2004

SOPAC’s Instantaneous Global Plate Motion Model: Contributions to a North-America Fixed Reference Frame

Bock, Y
Email: ybockucsd.edu
Address: Scripps Institution of Oceanography, IGPP 0225 9500 Gilman Drive,
La Jolla, CA 92093-0225 United States

Prawirodirdjo, L
Email: linettejosh.ucsd.edu
Address: Scripps Institution of Oceanography, IGPP 0225 9500 Gilman Drive,
La Jolla, CA 92093-0225 United States

Fang, P
Email: pfangucsd.edu
Address: Scripps Institution of Oceanography, IGPP 0225 9500 Gilman Drive,
La Jolla, CA 92093-0225 United States

Jamason, P
Email: pjamasonjosh.ucsd.edu
Address: Scripps Institution of Oceanography, IGPP 0225 9500 Gilman Drive,
La Jolla, CA 92093-0225 United States

We have implemented at the Scripps Orbit and Permanent Array Center an automated procedure whereby an instantaneous global plate motion model is updated on a regular (monthly) basis to improve its precision and reliability as new data become available, and as a baseline against which anomalous motions can be detected. The global plate motion model is for seventeen major and minor tectonic plates based solely on analysis of data from 133 globally distributed continuous GPS stations, spanning the period from January 1991 to the present. Site positions estimated from 24-hour segments of data are aligned day-by-day to the IGS realization of the ITRF2000 reference frame using a similarity transformation, thereby ensuring that the ITRF2000 No-Net-Rotation condition is preserved and that our plate motion model is absolute. Linear velocities of a carefully selected set of stations are estimated from the position time series, along with annual and semi-annual fluctuations and position offsets due to GPS instrument changes. A white noise plus flicker noise model is applied to estimate realistic uncertainties for the site velocities, which are then propagated into the derived plate motion model parameters. We also examine the vertical velocities in the site selection process. Here we consider the stability of a North-America fixed reference frame, in terms of changes in the monthly updates of the global plate motion model. We discuss the implications and limitations of this frame for PBO, the new definition of a North America datum, and the California Spatial Reference System maintained by the California Spatial Reference Center.

URL: http://sopac.ucsd.edu/processing/coordinates

Last modified: 2019-12-24  02:12:53  America/Denver